Introduction

Incidents in virtual environments can begin with a software vulnerability, human error, a configuration weakness, or several of these factors at once. The investigation is rarely limited to the workload. Hypervisors, container runtimes, management consoles, monitoring platforms, identity systems, virtual networks, datastores, backups, and automation accounts all influence what an attacker can reach.

Kaspersky GERT recently investigated two more ransomware cases on ESXi and Proxmox environments in which weak access controls, insufficient network separation, exposed administrative services, and poor management of privileged credentials contributed to the impact. A monitoring system that could reach the virtualization layer also exposed a reusable root credential. Once the attacker controlled that route, ordinary administrative access was enough to affect several hosts. No VM escape was required.

The incidents show why patching and secure configuration must be managed together. A fully patched hypervisor can still be compromised through a shared password, an overprivileged monitoring account, an open SSH path, or an administrator interface reachable from a general server network. NIST guidance places secure configuration baselines, restricted administrative access, current patches, and monitoring across all layers within the same set of sound security practices.

In this article, we’re going to describe both incidents with additional focus on common unsafe practices that were exploited, leading to compromise, as well as remediation tactics. We’ll also discuss the broader scope of threats targeting virtual environments for a better understanding of possible protection strategies.

The connected system defenders must protect

A business virtual environment is not just Hyper-V, VMware, or Docker but rather a connected stack. Management consoles, orchestration tools, monitoring platforms, and automation accounts sit above hypervisors and container engines. Registries, image stores, virtual switches, datastores, and backup systems connect the layers. Applications and business services run at the bottom, while much of the administrative power sits near the top.

The important boundaries extend beyond guest to host. They include workload to management plane, monitoring system to hypervisor, registry to deployment, administrator workstation to console, management plane to storage, and one virtual network segment to another. An attacker only needs one usable route. The possibility of compromise may lie in one stolen or insecurely placed administrator credential rather than in a complex escape exploit. In the GERT case, the compromise route passed through the monitoring platform and included a valid virtualization platform credential.

Case #1: From network monitoring to ESXi encryption

The investigation began with evidence of BlackNevas ransomware activity on a Windows system in a virtualized domain controller segment. UserAssist artifacts recorded execution of the AnyDesk RMM tool and GMER binaries. The environment also used PRTG Network Monitor to monitor its virtual infrastructure.

UserAssist artifacts

The available evidence showed that the PRTG deployment had broad access to the ESXi hosts and that the same root password was reused across several nodes. After obtaining access to the monitoring environment, the attacker used the ESXi credential to connect over SSH to the hosts that shared the same password. This design joined monitoring, credential storage, and direct administration into one attack path.

PRTG supports storing VMware credentials at the device or inherited group level. That feature is operationally useful, but a monitoring server becomes privileged infrastructure when it holds credentials that can administer the systems it observes. The security question is therefore not whether monitoring needs access, but whether the identity, privileges, storage method, and permitted network path are limited to the monitoring task.

The threat actor gained root access to the ESXi environment and used the esxcli command to bypass the system restriction by disabling the execInstalledOnly policy to execute the encryption binary and also perform anti-forensic log deletion. Let’s look closely at the timeline of the initial host compromise.

ESXi (192.168.*.*) timeline

2025-10-18 Connection attempts from IP address 192.168.*.*.
2025-10-19 During an SSH session by root from IP 192.168.*.*, the file esx is uploaded to the system.
2025-10-19 User "root" attempts to execute the binary esx with the error "Execution of non-installed file prevented".
	chmod 777 esx
	./esx /log
2025-10-19 User "root" deactivates the execInstalledOnly option.
	esxcli system settings advanced set -o 
	/User/execInstalledOnly -i 0
2025-10-19 User "root" executes the malware esx.
2025-10-19 New connection attempts from IP 192.168.*.*.

Now, at the same time, the following activities ensued on a different host with the same password for the root user:

ESXi (172.16.*.*) timeline

2025-10-19 SSH connection by user "root" from IP 172.16.*.*.
2025-10-19 User "root" executes the malware esx and clears the logs.
	chmod a+x esx && chmod 777 esx
	./esx /selftest
	nohup ./esx /p /vmfs/ /depth 5 /log /wipe
	./esx /depth 5 /log /wipe

Case #2: Credential notes impacting the whole Proxmox environment

GERT responded to a ransomware incident by The Gentlemen group, in which the threat actor gained access to Proxmox using information collected during the dwell time between initial access and visible impact. On a compromised system administrator workstation, the actor discovered administrative credentials and access details stored in notes in plain text. These records provided the information needed to log in to Proxmox using the root account.

The actor then activated the VNC web socket through the compromised root account, gaining extensive control over the Proxmox environment. This access was subsequently used to download and execute ransomware within the cluster, which resulted in the encryption of the entire virtual environment. Below are the log records showing the root account being used to access other hosts via a VNC web socket.

root@pam [01/08/2026:00:28:36 -0400] "GET /api2/json/nodes/******/vncwebsocket?port=5900&vncticket=****
root@pam [01/08/2026:00:30:17 -0400] "GET /api2/json/nodes/******/vncwebsocket?port=5900&vncticket=****
root@pam [01/08/2026:00:31:19 -0400] "GET /api2/json/nodes/******/vncwebsocket?port=5900&vncticket=****
root@pam [01/08/2026:00:43:38 -0400] "GET /api2/json/nodes/******/vncwebsocket?port=5900&vncticket=****
root@pam [01/08/2026:00:44:49 -0400] "GET /api2/json/nodes/******/vncwebsocket?port=5900&vncticket=****

This incident is a clear example of the risks of storing privileged credentials in unsecured notes or other easily accessible files. Once the administrator workstation was compromised, the saved credentials allowed the actor to move from a single endpoint into the virtualization management layer. Because the credentials belonged to a highly privileged root account, one poor credential handling practice significantly increased the scope and impact of the attack. Privileged credentials should instead be stored in an approved password manager or privileged access management system, protected with multifactor authentication and rotated immediately if an administrator workstation is suspected of being compromised.

Why the misconfiguration caused broad impact

Both cases exhibited unsafe misconfiguration practices whose exploitation led to a bigger impact on the host system. Next, we will break down each misconfiguration to see how it enabled further compromise and what should be done to avoid it.

Monitoring inherited excessive privilege

In Case 1, the monitoring platform could do more than collect health and performance data. It held or could use credentials with enough privilege to reach ESXi directly. A compromise of the monitoring system therefore became a compromise of the management plane. Monitoring identities should be dedicated to the task and given only the permissions required by the deployed sensors.

Credential reuse

Password reuse converted one recovered secret into farm-wide access. System administration should use named identities through the central management plane. Each host should have unique credentials and proper password storage hygiene. Password strength alone does not limit the impact of theft, but where the credential can be used and where it is stored do.

Direct root access bypassed central control

Direct SSH access allowed the actor to authenticate as root, upload a binary, and change a security setting without first passing through vCenter role controls. Broadcom, the parent company of VMware, recommends managing vSphere through vCenter, disabling SSH during normal operation, and using Lockdown Mode where suitable. Required service accounts should be explicit exceptions rather than members of a broad administrator group.

Lack of enhanced security settings

The initial execution attempt was blocked by execInstalledOnly, but the attacker had enough privilege to disable this policy. Broadcom documents enforcement options that combine execInstalledOnly with UEFI Secure Boot and TPM-backed configuration protection. These controls must be enabled, tested, and monitored for change. A setting that can be silently disabled by the same credential used for daily administration provides limited resistance after account compromise.

Unsafe credential storage

Case 2 demonstrated the possibility of compromise lying in privileged credential exposure. The mitigation strategy involves not only securing the administrative credential storage but also general hardening practices of secret handling, such as privilege management and regular access audits.

How to close this attack path

In this section, we share remediation advice on how to mitigate such attacks, and detect and prevent them from going further. We recommend the following actions:

• Separate monitoring from administration. Create a dedicated monitoring identity for each platform and restrict it to the smallest set of objects and actions that the monitoring sensors require. Do not use ESXi root or another emergency account for routine polling. Prevent monitoring servers from starting interactive administrator sessions unless a separately approved support workflow requires it. The same principle applies beyond VMware.
• Replace stored root passwords. Locate every copy of hypervisor, management, storage, and backup credentials in monitoring tools, scripts, scheduled tasks, connection managers, and service configurations. Replace static passwords with vault retrieval, brokered identities, or limited API tokens where the platform supports them. Record every retrieval and rotate the secret after emergency use or compromise.
• Restrict direct host access. Route normal ESXi administration through vCenter and enable an appropriate Lockdown Mode after testing monitoring, backup, and recovery dependencies. Keep ESXi Shell and SSH stopped by default. When support work requires SSH, enable it for a defined period, restrict the source, and alert on service activation, root login, and changes to the exception list of users who are allowed to connect via SSH.
• Use a specialized security solution. In our portfolio, Kaspersky Cloud Workload Security (KCWS) is perfectly suited to address virtual environment risks, offering a powerful combination of two products: Kaspersky Hybrid Cloud Security (KHCS) and Kaspersky Container Security (KCS). Kaspersky Hybrid Cloud Security is specifically built to secure virtualized infrastructures, private data centers, and hybrid clouds. A patented Light Agent architecture minimizes resource impact without compromising performance, while comprehensive infrastructure visualization through a unified console gives administrators complete visibility and control over the entire hybrid network. Kaspersky Container Security covers every stage of a containerized app’s lifecycle, from development to operation. Among other capabilities, the solution allows for detecting misconfigurations using a dedicated scanner for images, file systems, and repositories that contain IaC files (such as Terraform, CloudFormation, Azure ARM templates, Helm charts, and Dockerfiles).
• Treat configuration changes as security events. Alert when execInstalledOnly, Secure Boot enforcement, Lockdown Mode, SSH, local accounts, exception users, firewall rules, or remote logging settings change. Baseline the expected state and test whether the security team can detect an unauthorized change. A secure configuration set once does not mean that the control remains active on the host.
• Isolate the management network. Place hypervisor, monitoring, backup, storage, and cluster administration on restricted management networks. Permit only the exact source and destination services required. Administrative workstations should enter through hardened jump hosts with named identities and multifactor authentication.
• Protect logs, backups, and recovery. Forward ESXi, vCenter, Proxmox monitoring, identity, and network logs to protected storage that a compromised administrator cannot erase. Backup platforms should use separate identities, restricted management paths, and recovery copies outside ordinary administrative reach.

Configuration checks for monitored virtualization

Below are recommended checks to run when enabling virtualization monitoring. The safest state depends on the platform and monitoring method, but each control should be tested.

The wider attack surface

Closing the monitoring and credential routes does not secure the environment by itself. Virtualization also relies on isolation boundaries, trusted images, management APIs, virtual networks, storage, and backups. Each layer requires a different control and leaves evidence in a different place.

VM and container escapes

In a VM escape, code inside a guest reaches past the VM boundary and affects the host or another guest. The weakness may be in a virtual device, an integration feature, a hypercall interface, or another component that translates guest requests for the host. If the escape works, control of one VM may lead to control of the physical server and every workload on it. VMware CVE-2025-22224 showed this risk: an attacker with administrator rights inside a VM could execute code as the VMX process on the host, and Broadcom reported exploitation in the wild.

A container escape can reach a similar result, but the starting point is different. Linux containers share the host kernel, so their isolation model differs from that of a VM. Namespaces limit what processes can see, cgroups control resource use, and capabilities split root privileges into smaller parts. A kernel or runtime bug can break this isolation. Copy Fail (CVE-2026-31431) is a good example of a kernel flaw. Code already running in a container could use a Linux AF_ALG crypto socket to change pages in the shared Linux kernel page cache. Because the host and other containers may read the same cached pages, the effect did not have to stay inside one container. The fix is a kernel update; Docker Engine 29.4.3 also tightened its default security profiles to reduce exposure on hosts that had not yet been patched.

Unsafe settings can also break the boundary. Privileged mode, excessive capabilities, writable host mounts, or access to the Docker socket may remove isolation without any software exploit. For instance, runc CVE-2024-21626 involved leaked file descriptors that could expose the host filesystem to a malicious image or container process.

This difference changes the investigation. A VM can often be treated like a separate computer with its own kernel, memory, and disk. A container is a group of host processes placed inside namespaces. If investigators collect only the container filesystem, they may leave the most useful process, socket, and control-plane evidence on the host.

Images and templates

A compromised golden VM image or container base image can spread through normal automation. Common weaknesses include unofficial public images, mutable tags, overprivileged build tokens, recoverable secrets in older layers, and stale templates that restore vulnerable software or forgotten accounts. Scanning might help, but it does not establish who built the artifact or whether the exact image tested and approved was the one ultimately deployed to production. Use controlled builders, provenance records, signature checks, and planned rebuilds from trusted sources.

Management tools and APIs

A stolen vCenter identity, exposed Docker API, overpowered Portainer role, or compromised backup console may give an attacker an easier route than an escape exploit. Portainer advisory GHSA-7fw3-x4r2-g7wc showed how a proxy validated one bind-mount representation but missed an equivalent API form, allowing an authenticated non-administrator with container creation privileges to reach host paths. The runtime performed a valid request after authorization had already failed in the management layer.

Administrative file-copy operations also deserve attention. Docker fixed archive and mount-handling flaws in CVE-2026-41567, CVE-2026-41568, and CVE-2026-42306. These cases required particular conditions and operator or API activity. They are a reminder to patch the daemon and record who initiated copy operations, which container was involved, the source and destination paths, and the result.

Virtual networks, storage, and backups

East-west traffic between virtual workloads may stay inside one host and bypass a physical sensor. Management, migration, storage, and workload traffic should use separate zones with filtering between them. Snapshot and memory files may contain credentials, while weak datastore permissions can expose whole virtual disks. Backup systems need broad access to recover services, which also makes them valuable to an attacker who wants to delete recovery points or reach several hosts.

Attack surface examples by layer

To sum up, the described attack vectors might be mitigated as follows:

Conclusion

GERT cases that we presented in this article did not require an attacker to break the VM boundary. The attack path was created by an overprivileged monitoring relationship, an insecure password storage approach, a recoverable and reused root credential, broad management-network reachability, and direct SSH administration. Each element was legitimate on its own, but together they allowed one compromise to reach virtualization hosts and their workloads.

Misconfiguration should therefore receive the same operational attention as vulnerability management. Teams need to know where privileged credentials exist, which systems can use them, which network paths make them effective, and which logs will show their use. Escape flaws, unsafe images, API weaknesses, virtual network exposure, and attacks on storage or backups remain serious, but closing the known administrative route should come first.

Certificates both protect TLS connections and digitally sign applications, and forged ones turn up in real-world attacks from time to time. We’ve seen forged or stolen certificates abused by the DarkHotel APT and the Flame malware, and in 2011 we saw attack attempts after the certificate authority Comodo was compromised. Pulling off this trick usually takes serious expertise. But attacking eMudhra certificates in 2026 doesn’t take much effort at all. An attacker just has to guess a number from 1 to 255. Private keys for intermediate certificate authorities are normally gigantic numbers. But in this case, eight of them were the following: 4, 56, 66, 115, 155, 156, 230, and 237. They could be guessed using the public keys (available in public certificates) in under a second. As a result, a hypothetical attacker could issue certificates for anything by signing them with one of the compromised private keys.

Six of these keys were meant for issuing TLS certificates, and the other two were for code signing. All eight intermediate certificate authorities (CAs) were also cross-signed by the Sectigo CA. This means clients with different trust chains could trust a forged certificate.

The major browsers have already blocked the dangerous certificate chains. But IT and security teams still need to assess and remediate the risk in many other systems across their organizations. Scripts for scheduled data-processing, corporate NGFWs, monitoring servers, applications with built-in certificate stores, and devices that don’t get regular updates may accept forged certificates and be vulnerable to man-in-the-middle (MitM) attacks. The keys needed for this are already built into publicly available interception tools.

Timeline of the eMudhra certificate authority incident

The problematic keys came from a batch of 24 intermediate CAs that eMudhra created on April 30, 2025. Instead of cryptographically random values for a 384-bit elliptic curve, eight of the keys turned out to be small numbers. According to eMudhra’s own description, a “key wrap/unwrap step” during key generation created a second, weak set of keys. Because keys are created and stored in a dedicated device called a hardware security module (HSM), a weak key is hard to notice on its own. It’s still unclear what error caused the keys to be generated twice and the weak set to be used; the investigation is ongoing.

In May 2025, the Sectigo CA signed all eight intermediate certificates. Then, on October 17, 2026, an independent researcher notified the security teams at Mozilla, Google, and Apple, as well as the CA itself, that the keys were recoverable. On October 20, Mozilla publicly disclosed the incident. This means that for almost a year and a half the keys could have been recovered and certificates forged.

On October 22, eMudhra announced that it was exiting the global SSL/TLS certificate business.

What an attacker can do

Using the vulnerable intermediate CAs, an attacker can sign a forged certificate for someone else’s domain. Clients that still trust that chain and have no other safeguards will take the forgery for the real server.

A certificate alone isn’t enough to intercept HTTPS traffic. The attacker also needs a way to tamper with the victim’s traffic or redirect the connection. That’s possible, for example, in a compromised office network, on a Wi-Fi access point the attacker controls, or by interfering with routing and DNS. And all of this does happen in the wild, as the DarkHotel attacks, among others, have shown.

There’s one more danger: two of the keys can be used for code signing. In theory, that would let an attacker deliver malware that appears to come from a trusted vendor and doesn’t trigger scary OS warnings during installation.

Was it exploited?

Experts from various companies who analyzed the after-effects of the incident haven’t found any malicious attacks that used these certificates. eMudhra and CERT-In have also reported finding no abuse. The Chrome team found no certificates from the six CAs in public Certificate Transparency logs.

This means that systems where browsers check certificates through Certificate Transparency (CT) were most likely not attacked. But many devices and applications — especially servers and IoT devices, don’t check CT at all, so we can’t say anything about them. Today, malicious actors no longer need to write their own hacking tools to pull off an attack like this. Version 12.3 of mitmproxy — a popular tool among security researchers — already has built-in support for compromised keys.

Where the risk has been eliminated, and where that isn’t guaranteed

Major platforms quickly revoked the compromised certificates. As early as October 17, Chrome did so through CRLSets, and Firefox — through OneCRL. On October 18, eMudhra itself revoked the certificates, citing “CA Compromise”. Apple took action on October 19, and the Sectigo CA also revoked the cross-signed copies. Microsoft revoked the certificates on October 20. Depending on the settings of a specific application and OS, revocation may have taken effect even without an application update, since blocklists are often updated separately.

At the same time, a more radical measure is under way: withdrawing trust from the root CA. Chrome has announced the planned removal of “emSign ECC Root CA – G3” from the browser. Certificates issued under the “emSign Root CA – G1” root, and the root itself, aren’t affected. According to eMudhra’s estimate, about 30 000 certificates will need to be migrated.

But certificate revocation only works where the client can find out about the revocation to then be able to actually act upon it. Many applications check the signature, server name, and certificate validity period, but don’t retrieve or update blocklists. Here are the typical cases:

Outdated and LTS systems. LTS (long-term support) status alone doesn’t mean a system is vulnerable. By definition, a system with this status receives support. But old containers, frozen OS images, and systems that are no longer updated can keep trusting revoked CAs for a long time. It all depends on updates to ca-certificates and TLS libraries, and the settings of the specific application.

Automated systems and servers. On emudhra.we-have-a-problem.com — a site created by enthusiasts where you can check any client software for misplaced trust — curl and Zabbix dominate the list of the most vulnerable systems. For HTTP checks, Zabbix usually uses libcurl and the certificate store configured for it. Similar behavior is also documented in the built-in curl in macOS. At the OS level and in Safari, the certificate is revoked, but curl reads a plain /etc/ssl/cert.pem file, and that’s precisely where the fix has to be made. This is a good example: even when system-level trust and revocation mechanisms work, individual applications — including ones that ship with the OS by default — can remain vulnerable.

Python, Ruby, Go, Java, and containers. An application may use its own set of root CAs, which isn’t updated along with the OS. Endor Labs found more than 25 popular packages that contain the affected root.

Slack, GitHub Desktop, and other apps built on the Electron framework. These apps ship with their own Electron/Chromium, so updating a separately installed Chrome doesn’t update Slack. The certificate revocations are already in the new Electron version, but now every developer has to rebuild and distribute their app, and every user has to install the update. That said, not every Electron app is necessarily vulnerable. The outcome depends on the version, how the app updates its blocklists, and which network stack it uses.

Mobile browsers and IoT devices. Mobile Chrome, Firefox, and Safari get certificate revocation data as quickly as their desktop counterparts do. With the stock browsers from smartphone makers, this isn’t the case. In a published test, Samsung Browser 31.0.0.64 accepted all six test chains from emSign while rejecting the ones from Sectigo. For HarmonyOS 6 and 7, researchers found the affected CAs in Huawei’s published list of root CAs, and those CAs can’t be revoked manually.

For unsupported devices, home appliances, and old firmware, a certificate store update may never be released. In those cases, the problem could linger for years.

Impact on TLS inspection in a corporate network

When an NGFW or web gateway inspects encrypted traffic, it maintains two connections: one with the client and the other with the external server. The client receives a certificate signed by the corporate CA, while the gateway itself verifies the authenticity of the external server.

If the gateway accepts a forged eMudhra certificate, even an updated browser on an employee’s computer won’t see the dangerous chain. Instead, it will receive the familiar corporate certificate. In this scenario, the security tool itself hides the problem from the client. That said, carrying out such an attack would also require intercepting traffic.

To fix the validation policy and certificate lists on the inspection device itself, follow the vendor’s instructions — if the vendor has published any, that is.

At Cisco, the status of the issue is documented in detail for all products. Most of them are still listed as “under investigation”, but mitigation measures are recommended for vulnerable devices.

Sophos and Check Point promise device software updates and, in the meantime, advise removing the certificates manually. Neither company has published a security advisory, but employees of each posted recommendations on its support forum.

For Fortinet devices, instructions for checking and removing emSign certificates can be found here. Palo Alto offered only general advice instead of specifics for its own products.

Of course, a properly configured gateway can indeed temporarily protect outdated client devices that trust the dangerous certificates.

To check specific devices, services, containers, and virtual machines, you can use a dedicated website. One possible scenario for proactively hunting for threats that exploit or have previously exploited weak keys is described here.

On October 27, Google issued a new Stable channel update for Chrome.

Most users are on Chrome’s Stable channel. The desktop update brings Chrome to versions 156.0.8078.73/.74 for Windows and Mac and 156.0.8078.73 for Linux. The update includes 52 security fixes, including four rated Critical.

On the same day, Mozilla issued Security Advisory 2026-118, which fixes 167 vulnerabilities. Firefox 159 also introduces several new features.

Both updates will roll out over the coming days and weeks.

How to update Chrome

The easiest option is to allow Chrome to update automatically. But you can end up lagging behind on updates if you never close your browser or if something goes wrong, such as an extension preventing the update.

If you don’t want to wait for the rollout to reach you, manually updating is easy. Open About Google Chrome from Chrome’s settings or Help menu. Chrome will check for updates. If one is available, click Relaunch to apply it.

You can find an explanation of the version numbering system and step-by-step instructions in our guide: How to update Chrome on every operating system.

How to update Firefox

To update Firefox, open the browser and click the menu button at the right side of the Firefox toolbar, then go to Help and select About Firefox. The About Mozilla Firefox window will open.

Firefox will automatically check for updates. If one is available, it will be downloaded. Once done, you’ll be prompted to click Relaunch. After Firefox restarts, it will be up to date.

Technical details

These Chrome and Firefox updates address a familiar problem: browser code mishandling memory while processing web content. Both releases fix use-after-free vulnerabilities, including flaws in page layout, JavaScript processing, and SVG graphics.

A use-after-free vulnerability occurs when a program attempts to access a memory location after it has been freed. That can cause crashes or, in some cases, allow an attacker to run their own code.

There’s another connection between these updates: both Google and Mozilla credit OpenAI Codex Security with finding bugs fixed in these releases. AI can help security teams examine browser code for weaknesses, alongside human code reviews and automated tests that check how software handles unexpected inputs.

Mozilla’s collaboration with Anthropic shows how AI-discovered findings can lead to fixes: researchers validated vulnerabilities before reporting them, giving Mozilla’s team reproducible bugs to investigate, repair, and deliver to users.

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In November 2015, we released our first in-house macOS sandbox, Box of Apples, followed by an update in March 2018 that introduced HTML behavior reports, desktop screenshots, and process trees. Over the past decade, the macOS ecosystem and the threat landscape targeting it have changed dramatically. Apple transitioned its hardware architecture from Intel (x86_64) to Apple Silicon (ARM64), hardened its operating system security model, and deprecated legacy dynamic tracing mechanisms. At the same time, macOS threat actors have shifted toward native ARM64 binaries, multi-stage social engineering installers, credential-harvesting AppleScripts, and evasive infostealers.

Today, we are excited to introduce macOS Mirage, our brand-new, ground-up dynamic analysis sandbox built natively for Apple Silicon and macOS 26. macOS Mirage replaces Box of Apples as part of the VirusTotal Multi-Sandbox project, delivering high-fidelity behavioral telemetry, automated Sigma behavioral detections mapped to MITRE ATT&CK, and—exclusively within our Private Scanning product offering—full Interactive Live Analysis.

Why We Built macOS Mirage: Beyond Box of Apples

Box of Apples was designed for an era of Intel-based Macs and relied on dtrace scripts to monitor system calls. As macOS evolved, two structural shifts required a completely new approach:

1. Native Apple Silicon (ARM64) Execution: Modern macOS applications and malware families are compiled natively for Apple Silicon or distributed as Universal Mach-O binaries. Running modern samples on legacy Intel hardware either fails outright or misses architecture-specific execution paths. macOS Mirage runs natively on bare-metal Apple Silicon hardware with Apple's native virtualization stack and macOS 26, ensuring authentic execution fidelity.
2. Modern Kernel-Backed Behavioral Telemetry: In modern macOS releases, System Integrity Protection (SIP) restricts legacy dtrace hooks, and high syscall volumes could cause event drops. macOS Mirage uses modern, kernel-supported macOS security instrumentation to capture process creation, command-line arguments, file system modifications, persistence installation, and access to sensitive credential stores without losing events.

Rich GUI Execution and Persistence Tracking

Many macOS samples package their payloads inside disk images (.dmg) or application bundles (.app) that initialize graphical windows, register background services, or trigger system notifications during execution. macOS Mirage provides full graphics acceleration and desktop monitoring, capturing both visual screenshots and underlying system modifications in real time.

Figure 1: Dynamic detonation of a macOS application in macOS Mirage, capturing both the application GUI and a macOS system notification alerting to a newly registered persistent background Login Item.

Figure 2: Full window management, 3D rendering, and Dock process tracking inside macOS Mirage.

In addition to capturing screenshots to show what a user would see on screen, macOS Mirage automatically monitors security-sensitive locations across the operating system, including:

• Persistence Mechanisms: LaunchAgents, LaunchDaemons, Login Items, and cron jobs.
• Shell & Environment Profiles: Modifications to .zshrc, .bashrc, .zshenv, and /etc/profile.
• Credential & Privacy Stores: Unauthorized access to Keychain databases (login.keychain-db), browser cookie and credential stores, SSH keys, and the Transparency, Consent, and Control (TCC.db) database.
• System & Network Configuration: Changes to /etc/hosts, /etc/resolv.conf, and /private/etc/sudoers.

New Behavioral Detections with Sigma Rules: Catching a macOS Info-Stealer in Action

To help analysts quickly identify malicious behavior without sifting through thousands of raw file and process events, macOS Mirage evaluates runtime telemetry against a curated library of macOS Sigma rules and maps every detection directly to MITRE ATT&CK techniques.

Let's look at a real-world example of a macOS info-stealer and credential-phishing sample analyzed by macOS Mirage on VirusTotal: be77bca22f078d57058535ddcf26a39a752a8df030392cb45ba6a60e06651878

When executed inside macOS Mirage, the binary (unix51436504) performs a multi-stage credential theft and persistence chain:

1. AppleScript Password Phishing: The malware invokes /usr/bin/osascript to display a deceptive system prompt titled "Password Request" asking the user: "Please enter device password to continue."
2. Local Credential Validation & LaunchDaemon Persistence: It validates the harvested password against local Directory Services (dscl . authonly) and invokes sudo -S to copy /tmp/daemonplist to /Library/LaunchDaemons/com.somedaemon.plist.
3. Keychain, Browser & Notes Harvesting: The sample opens the user's Keychain (/Users/admin/Library/Keychains/login.keychain-db), Safari cookies (Cookies.binarycookies), Apple Notes database (NoteStore.sqlite), SSH keys (authorized_keys, known_hosts), and .zsh_history, staging the stolen files under /tmp/lksopo while continuously polling the clipboard via pbpaste.
4. Secondary Payload Download, Exfiltration & Cleanup: Using ditto, the malware compresses the staging directory into /tmp/lksopo.zip, exfiltrates the archive via an HTTP POST request (curl -X POST), downloads a secondary bot payload (curl -o /tmp/binaryexe), and deletes the staging directory (rm -rf /tmp/lksopo) to cover its tracks.

Figure 3: macOS Mirage screenshot capturing the deceptive AppleScript "Password Request" phishing dialog displayed by sample be77bca22f078d57058535ddcf26a39a752a8df030392cb45ba6a60e06651878.

From this single detonation, macOS Mirage automatically generates a high-confidence malicious verdict (macos_osascript_credential_phishing) and triggers 7 distinct Sigma rules spanning the entire attack lifecycle:

Hunting Related Threats with VirusTotal Intelligence Pivots

At the time of analysis, sample be77bca22f078d57058535ddcf26a39a752a8df030392cb45ba6a60e06651878 was detected by only 6 out of 76 static antivirus engines. Moreover, during execution inside macOS Mirage, the first-stage dropper downloaded and executed a 12.9 MB universal Mach-O second-stage bot (f7dcdc4167ec267aef007f9d5f98e9e0314185e5355effd3e304b6fa686ea84c) alongside a LaunchDaemon persistence property list (d7dd630f67e03d2945185838dca887211ea3693c91fc0bd0d2e257948bb3b678, 0/75 AV detections). When that second-stage binary is detonated in isolation, it exits in under a second because it depends on hidden state files (~/.bhost, ~/.phost, ~/.username, ~/.pwd) written to disk by the first-stage dropper. Because macOS Mirage tracks the full multi-stage process tree on macOS 26, analysts can pivot directly on runtime command lines, dropped artifacts, network URI patterns, and Sigma detections across VirusTotal Intelligence to uncover entire clusters of active macOS campaigns. For a complete reference of supported file and behavior query syntax, see the VirusTotal Search Modifiers Full List.

1. Process & Command-Line Pivots (behaviour_processes)

• Custom Exfiltration curl Headers: Hunts samples exfiltrating staged archives with custom buildid: and username: HTTP headers across rotating C2 servers: behaviour_processes:"curl -X POST -H buildid:"
• AppleScript Phishing Dialog Variable: Pinpoints samples spawning osascript with the passwen password dialog variable: behaviour_processes:"set passwen to display dialog"
• Second-Stage Bot Payload Delivery: Matches command lines downloading the persistent implant from /web/bot: behaviour_processes:"/web/bot"
• Staging Archive Compression via ditto: Identifies Mach-O stealers compressing harvested credentials in /tmp/ using Apple's ditto utility: behaviour_processes:"ditto -c -k --sequesterRsrc /tmp/" type:macho

2. Dropped File & Hidden State File Pivots (behaviour_files)

• Hidden Bot C2 Configuration in $HOME: Finds samples writing hidden bot configuration files (~/.bhost, ~/.phost, ~/.botid) into the user's home directory: behaviour_files:".bhost"
• Hidden Second-Stage Bot Executable: Matches samples dropping the persistent second-stage payload to $HOME/.binaryexe: behaviour_files:".binaryexe"
• LaunchDaemon Persistence Plist: Uncovers samples installing system-wide persistence at /Library/LaunchDaemons/com.somedaemon.plist: behaviour_files:"/Library/LaunchDaemons/com.somedaemon.plist"

3. C2 & Network Pivots (behaviour_network)

• Infrastructure-Agnostic Bot Check-In URI: Matches the /api/v1/bot/joinsystem// check-in endpoint across all C2 IP addresses: behaviour_network:"/api/v1/bot/joinsystem"
• Exfiltration Collector Server: Pivots on samples posting stolen Keychain, Safari cookie, and Notes archives to 109.238.87.111: behaviour_network:109.238.87.111
• Second-Stage Bot C2 Server: Pivots on samples retrieving /web/bot and polling /api/v1/bot/actions/ on 193.178.159.129: behaviour_network:193.178.159.129

4. macOS Mirage Verdict, Sigma & MITRE ATT&CK Pivots

• macOS Mirage Credential Phishing Verdict: Surfaces Mach-O stealers convicted by macOS Mirage's macos_osascript_credential_phishing detection across distinct malware builders (commandbuild-* and macos-stealer-v2-*): sandbox_name:"VirusTotal MacOS Mirage" behaviour:"macos_osascript_credential_phishing"
• macOS Mirage PASSWORD_DIALOG Behavioral Tag: Finds Mach-O binaries displaying deceptive credential prompts during macOS Mirage execution: sandbox_name:"VirusTotal MacOS Mirage" behaviour_tags:PASSWORD_DIALOG type:macho p:5+
• Sigma Suspicious /tmp/ Execution in macOS Mirage: Hunts samples matching Sigma rule b8017658b8eef8b1293176d76212e600b660d0a36a4f5dc80141324fae360bbf (Potentially Suspicious Execution From Tmp Folder): sandbox_name:"VirusTotal MacOS Mirage" sigma_rule:b8017658b8eef8b1293176d76212e600b660d0a36a4f5dc80141324fae360bbf p:5+
• MITRE ATT&CK Keychain Credential Access (T1555.001): Identifies Mach-O samples flagged by macOS Mirage for targeting macOS Keychain credentials: sandbox_name:"VirusTotal MacOS Mirage" attack_technique:T1555.001 type:macho p:5+

Interactive Live Analysis (Exclusive to Private Scanning)

While automated dynamic analysis and Sigma behavioral detections are available on VirusTotal reports, sophisticated macOS threats often require human interaction to detonate completely. Malware may hide behind multi-step custom installer wizards, require a password to unlock a disk image, or pause execution until realistic user input is provided—just like the "Password Request" dialog shown above.

To empower incident responders and malware analysts, Interactive Live Analysis with macOS Mirage is available exclusively as part of our Private Scanning product offering in Google Threat Intelligence and VirusTotal Enterprise:

• Real-Time Mouse & Keyboard Control: Analysts can step directly into the running macOS 26 desktop inside their web browser to click buttons, navigate prompts, open Terminal, or manually interact with suspicious applications.
• Host-to-Guest Clipboard ("Send as Keystrokes"): Analysts can paste passwords, decryption keys, URLs, or terminal commands from their local workstation directly into the sandbox VM as simulated keystrokes.
• Extended Session Timeouts & Network Control: Interactive sessions can run for extended durations (up to 30 minutes) and can be configured with custom network routing modes—including full isolation, simulated internet services, HTTPS MITM inspection, or Tor routing.
• Complete Tenant Privacy: All files, interactive sessions, screenshots, and behavioral reports generated in Private Scanning remain strictly isolated within your organization's private environment and are never shared publicly.

Figure 4: Selecting macOS Mirage and enabling Live Interaction inside the Private Scanning configuration modal.

Figure 5: Using the "Send as keystrokes" clipboard bridge during a live interactive macOS Mirage session in Private Scanning.

Try It Out and Share Your Feedback

macOS Mirage is part of our ongoing commitment to expanding multi-platform dynamic analysis across VirusTotal and Google Threat Intelligence. To view the new behavioral reports on public samples, navigate to the Behavior tab on any macOS file report in VirusTotal to inspect process trees, file system changes, network activity, screenshots, and Sigma rule matches. Enterprise customers using Private Scanning can select MacOS Mirage directly from the scan configuration dialog to launch automated or live interactive sessions.

If you find any issues or have feature requests, please don't hesitate to contact us.

Happy hunting!

A domain that has long appeared in software documentation, code examples, and developer test material is now being used to push a ClickFix attack against Windows users.

A placeholder domain stands in for a website in an example. The best-known is probably example.com. Another, third-party[.]com, has often been used in documentation to represent an external website, API, or service.

However, there is a very important difference between the two: example.com is reserved for documentation, while third-party[.]com is an ordinary domain. Anyone could register it, and someone did. Every document, test, and skill that hardcoded it now points readers and users to the attacker’s infrastructure.

Researchers at Manifold Security found that third-party[.]com was serving a fake Cloudflare-style verification page to Windows visitors. The page tries to persuade them to open the Windows Run box and paste a command it has copied to their clipboard.This command is designed to download and execute a PowerShell script. At the time of writing the domain hosting the script is not resolving.

ClickFix is a social-engineering technique that turns the victim into the malware installer.

Instead of relying on a malicious attachment or an obvious executable download, the attacker convinces someone to run a command themselves. Common lures include:

• A fake CAPTCHA or Cloudflare Turnstile check.
• A browser error that claims it needs a “manual fix.”
• A bogus video-player, document-viewer, or popular software download.
• A support scam page that tells the visitor to paste a command into Run, Command Prompt, Terminal, or PowerShell.

ClickFix works because the command often uses legitimate Windows or Mac tools to download and execute the next stage. It also runs with the permissions of the person who has been convinced to enter it.

The consequences can range from information theft to more serious compromise of a company network. In a recent campaign called TerminalFix, a fake Cloudflare CAPTCHA led victims to paste a PowerShell command into Windows Terminal or PowerShell.

How to stay safe

With ClickFix running rampant—and it doesn’t look like it’s going away anytime soon—it’s important to be aware, careful, and protected.

• Slow down. Be wary of a webpage that urges you to run commands on your device, especially if it uses a countdown or other pressure tactic.
• Don’t run commands or scripts from untrusted sources. Never run code or commands copied from websites, emails, or messages unless you trust the source and understand the action’s purpose. Verify instructions independently. If a website tells you to execute a command or perform a technical action, check through official documentation or contact support before proceeding.
• Check what you’re pasting. A website may copy a command to your clipboard without showing you the full text. Don’t paste it into a command window.
• Secure your device. Use an up-to-date, real-time anti-malware solution with a web protection component.
  
• Educate yourself on evolving attack techniques. Understanding that attacks may come from unexpected vectors and evolve helps maintain vigilance. Keep reading our blog!

Pro tip: The free Malwarebytes Browser Guard extension warns you when a website tries to copy something to your clipboard.

Stop threats before they can do any harm.

Malwarebytes Browser Guard blocks phishing pages and malicious sites automatically. Free, one click to install. Add it to your browser →

Unit 42 is aware of possible 0-day activity against NetScaler devices. Citrix reports CVE-2026-88771, CVE-2026-88772 have been exploited in the wild.

The post Threat Brief: NetScaler Zero Days CVE-2026-88771 and CVE-2026-88772 Exploited in the Wild (Updated September 30) appeared first on Unit 42.

Analysis of how default configurations in AWS AgentCore Harness allow prompt injection to exfiltrate credentials, and key steps to secure your agents.

The post A Vault with a Heap-View: The Uncomfortable Space Between AgentCore Harness and Identity appeared first on Unit 42.

Learn how root access on a compromised K8s node allows attackers to utilize SPIFFE/SPIRE metadata to spoof and harvest co-located workload identities.

The post The Machine With Many Faces: Post-Exploitation Identity Misuse in SPIFFE/SPIRE appeared first on Unit 42.

Malicious extensions and ClickFix attacks are two hugely popular topics on our blog, and for a good reason: they’re both very common. In this post, we bring them together. Here’s the thing: in our posts about malicious ClickFix instructions, we don’t always explain exactly how users end up on the attackers’ pages in the first place. A recent study gives us a chance to fill that gap and talk about one of those methods: malicious extensions.

Readers who are not deep into cybersecurity may already have a bunch of questions at this point: how can extensions be malicious? where do they come from? and what exactly is ClickFix, anyway? Fret not: this post answers all these questions.

The danger of browser extensions

Let’s start with the basics. Browser extensions or add-ons are lightweight tools installed in your browser to give it extra capabilities or change how it works with web pages. For example, extensions can block ads, translate pages, download audio and video, save passwords, or take screenshots.

Most browser developers offer users an official extension store. For instance, for the most popular browser, Chrome, that store is the Chrome Web Store. There are also alternative platforms for distributing extensions, though browser developers have recently made it much harder to install and use extensions that don’t come from an official source.

Just like any other software, extensions can be useful, but they can also be malicious. In fact, cybercriminals often spread malicious extensions through those very same official stores, and we’ve covered plenty of such cases on our blog before.

It’s no accident that criminals love spreading malicious plug-ins. To work properly, most extensions need permission to read and modify the content of every web page the user visits. Without that permission, add-ons would be basically useless. For instance, a translation extension needs to read all the text on a page before it can swap the original for the translation.

Cybercriminals take advantage of these capabilities for their own purposes: for example, they intercept logins, passwords and other data entered on websites, swap out payment details, or show victims fake forms and messages. And all of this happens on legitimate sites that users have come to trust without a second thought.

Now let’s move on to a fresh piece of research about a campaign that spread 19 malicious add-ons through the Chrome and Edge extension stores. We’ll use it as an example to look at what these tools can actually do.

Almost twenty malicious extensions for Chrome and Edge

In late August, cybersecurity researchers reported finding 18 malicious extensions for Chrome and one for Edge. They said all 19 add-ons were probably linked to the same campaign. They base this on the similarity of the malicious code and the methods the attackers used. You’ll find the full list of malicious extensions at the end of this post.

Most of the extensions discovered, 14 in total, were built by the attackers themselves. Their first versions weren’t malicious at all and did exactly what users downloaded them for. But after a while, once users had come to trust the add-on, the attackers pushed an update that slipped in malicious functionality.

As for the remaining five extensions, their creators had nothing to do with the cybercriminals at all. They simply sold their creations to them. This way of getting hold of extensions is also popular among cybercrooks. There are plenty of reasons for that: ready-made add-ons can be bought for relatively little money, and criminals don’t have to build or promote them from scratch. And most importantly, along with the extension, they also inherit its existing user base. Upon buying the add-on, all the attackers need to do is add malicious functions and push an update that installs automatically for users. Users are never told that the extension’s real owner has changed.

In this case, the add-on cybercriminals bought most often was Enable Right Click & Copy — Smart Unlock + OCR. It had 70 000 users in Chrome and 10 000 in Edge. This purchase is exactly why there’s a single Edge extension among all its Chrome relatives. The add-on itself originally served a perfectly benign purpose: it let users select and copy text on sites where that’s normally blocked, and it could also pull text out of images with optical character recognition (OCR).

At the time of the research, the Edge version of the extension had more than 10 000 users. Source

The malicious functionality introduced into the extension makes it reach out to the attackers’ command-and-control (C2) server to download additional modules of nefarious code. These modules can change over time. Since Chrome automatically updates all installed extensions by default, the malicious version lands on the device without users having to do anything at all.

For the downloaded code to run on the websites the user visits, the extension disables one of their defenses — Content Security Policy (CSP). This mechanism allows website owners to declare which scripts and other resources are allowed to load and run on a page. Once this protection is turned off, the extension can inject code it gets from the C2 server right into the pages open in the browser. The website itself isn’t hacked, and it looks the same to everyone else, but for that one infected user, the legitimate page quietly turns malicious.

What these 19 extensions can do

Now let’s take a closer look at what the malicious modules loaded by the extension are actually capable of. Researchers found 16 such modules, built for all sorts of tasks: from stealing data and hijacking cryptocurrency to the ClickFix attacks we’re focusing on here.

Some of the modules simply collect user data. They intercept logins, passwords, email addresses, and other valuable information the user enters into web forms, including payment details. On top of that, the add-ons steal data from Facebook and LinkedIn accounts and collect browsing history. Criminals can use this information to take over accounts, steal money, and launch further attacks against the victim.

A few other modules focus specifically on stealing cryptocurrency and related data directly. One of them is a crypto drainer, a tool that empties crypto wallets. It works with Ethereum and compatible blockchains as well as Solana and Tron. It replaces the real Connect Wallet and Swap buttons on websites with its own fake ones. When a user clicks one of these buttons, the drainer takes over all further interaction with the wallet and walks the victim through confirming the actions needed to steal their cryptocurrency.

Other modules target users of Ledger and Trezor hardware wallets. Right on the official websites of these services, the malicious extension displays a fake wallet update-and-restore page that asks for a seed phrase of 12, 18, or 24 words. The seed phrase the user enters is forwarded straight to the attackers, giving them full control over the wallet.

The fake form asks the user to enter a seed phrase of 12, 18, or 24 words, which then ends up in the attackers’ hands. Source

Finally, some modules gather information from crypto service pages open in the browser, such as OKX, MEXC, Kraken, KuCoin, Coinbase, Binance, Bybit, and MetaMask, including balance details and active session data that can be used to hijack accounts.

And now we’ve finally reached the module that matters most for this post: the one used for ClickFix attacks. We’ll talk about it in the next part.

How malicious extensions are used in ClickFix attacks

The ClickFix attack technique has become extremely popular among cybercriminals lately. It relies on social engineering: the victim is shown fake instructions supposedly needed to complete some action, such as passing a CAPTCHA check, fixing an error, or updating a program. Following these instructions, the user copies the command suggested by the attackers, pastes it into a system tool built for running these commands, and runs it, all by themselves.

We’ve written about attacks like this and their consequences more than once on our blog. But we rarely dig into exactly how a victim ends up on a page with fake instructions in the first place. A campaign that spread malicious extensions through the Chrome Web Store shows us one way this can happen.

Add-ons turn out to be a very handy tool for ClickFix attacks. As we mentioned earlier, when a user visits a page, extensions are allowed reading and changing its content in order to work. That gives attackers the chance to swap in a fake ClickFix instruction at just the right moment, replacing the content of the page the person actually wanted to open.

What’s more, the ClickFix technique itself lets attackers break out of the browser and gain a foothold directly in the system. That means removing the malicious extension won’t necessarily undo the damage: after the user has run the ClickFix command, malware may already be installed outside the browser.

In the specific attack example the researchers describe, the user sees a fake notification saying their browser needs to be updated, along with instructions on how to do it. The instructions change depending on the operating system, and the extension picks up that information automatically too.

In the macOS version of this attack, the user is told to open Terminal, copy a command, paste it there and run it, then restart Chrome to supposedly finish the update. Source

How to avoid falling victim to infected extensions

First off, we recommend checking whether any of the following malicious extensions are already installed in your browser:

• Enable Right Click & Copy — Smart Unlock + OCR
• RapidLens – Google Lens for Screen Search & Images
• QuickLens – Search Screen with Google Lens
• Password Protect PDF
• Allow Copy – Select & Enable Right Click
• PixelCheck
• Creative Library – Ad Spy Tool
• Website Traffic Checker: MirrorSphere SEO Stats
• Site Signal – Website Traffic & SEO Checker
• SEO Pulse Pro – Website Traffic & SEO Analyzer
• Private Crypto News Reader
• Blockfolio: Address Monitor
• Crypto Rates & Fiat Converter
• Crypto Alerter: Price Alarms & Volatility Warnings
• DeFi Pulse Tracker
• Crypto Price Badge: Quick Glance
• Multi-Chain Explorer
• LedgerLook: Wallet Checker
• Meta & Facebook Ad Library Spy — Save Ads, Finder, Downloader | FeedX-Ray

If you find any of these extensions on your device, we recommend removing it as soon as you can and running a full system scan with a reliable antivirus. As we mentioned above, simply deleting the add-on might not be enough. You can use a free trial version to detect and remove the infection.

How to avoid falling victim to malicious extensions and ClickFix attacks in the future?

• Don’t install too many extensions and regularly check the list of those you have.
• Remove extensions you don’t use.
• Trust the warnings from your operating system and security software, rather than the instructions — or even the demands — of websites and apps.
• Install a trusted security solution on all your devices.

What else makes browser extensions and the ClickFix technique dangerous? Find out in our other posts:

• Bad advice for gamers: ClickFix hits Steam forums
• ClickFix on macOS: how Apple users are being scammed
• Infostealer has entered the chat
• AI sidebar spoofing: a new attack on AI browsers
• Dangerous browser extensions

Researchers at Hudson Rock found that cybercriminals hijacked HBO Max’s verified Reddit account and used it to run 108 malicious ads over roughly 48 hours.

The ads used HBO Max’s trusted corporate account to promote fake AI tools, developer software, and macOS utilities, lowering potential victims’ guards.

Some ads directed users to convincing HBO lookalike sites that claimed to offer a native HBO Max app for macOS or a promotional download. But instead of providing an installer, the sites instructed visitors to open Terminal on their Mac or, on Windows, the Run dialog or PowerShell, and paste in a command.

This is the hallmark of a growing social engineering technique known as ClickFix.

ClickFix attacks disguise malicious instructions as a routine technical step, such as fixing an error, completing a CAPTCHA, verifying that you are human, or installing software. A web page may silently copy a command to the clipboard, then guide the victim through pasting and running it, by which they will infect their own device.

Researchers at ADAMnetworks have dubbed the operation behind the HBO Max ads “PasteSwitch.” Its infrastructure appears to tailor the next stage to the visitor’s device and the lure being used.

Observed macOS payloads included MacSync and AMOS infostealers designed to steal browser credentials and profiles, Telegram data, Apple Notes, saved passwords, and cryptocurrency wallet recovery phrases.

Windows users could end up with the Amatera infostealer, which runs in memory. The operation has also been linked to cryptocurrency clipboard hijackers, which monitor copied wallet addresses and replace them with an attacker-controlled address before a transaction is sent.

How to stay safe

Reddit admins paused the ads and opened a security investigation after reports came in, but it is important to remain vigilant. Reportedly, ClickFix was responsible for more than half of all malware loader activity in 2025.

One reason for its success is that campaigns continue to add new methods for tricking users and different commands for avoiding detection.

Users of macOS Tahoe 26.4 or later may be warned when pasting text into Terminal, but it doesn’t appear for everyone, so you shouldn’t rely on that alone.

Malwarebytes can provide additional protection at several stages of a ClickFix attack. Browser Guard warns when a website tries to copy something to your clipboard, web protection blocks known malicious sites, and real-time protection can detect malware delivered by the campaign.

With ClickFix running rampant and inventing new methods all the time, it’s important to be aware, careful, and protected:

• Treat ads with caution. A verified account does not guarantee that an ad is safe. Visit the company’s official website directly instead of downloading software through an advertisement.
• Slow down. Don’t rush to follow instructions on a webpage or prompt, especially if it asks you to run commands on your device or copy-paste code. Attackers may use countdowns, user counters, or other pressure tactics to make you act quickly.
• Don’t run commands from untrusted sources. Never run code or commands copied from websites, emails, ads, or messages unless you trust the source and understand what the command does. Check the instructions against official documentation or contact the company’s support team.
• Secure your devices. Use an up-to-date, real-time anti-malware solution with a web protection component. Malwarebytes blocks ember-bridge.com, which is part of the PasteSwitch infrastructure.
  
• Educate yourself on evolving attack techniques. Understanding that attacks may come from unexpected vectors and evolve helps maintain vigilance. Keep reading our blog!

From reporting threats to removing them.

Cybersecurity risks should never spread beyond a headline. Keep threats off your devices by downloading Malwarebytes today.

Attackers typically try to pass off malware as legitimate applications or as potentially unwanted programs that users deliberately search for and download, such as cheats or cracks. They often rely on ad and affiliate networks to deliver their creations to victims’ devices. This post examines a less conventional case: a well-known backdoor distributed under the guise of adware. The attackers may have chosen this distribution method because the adware was signed by the developer. On top of that, users often manually add these apps to exclusions, so their useful features don’t get blocked.

Some time ago, a client asked us to analyze a file with the MD5 hash c24e99f9437feacaa63766a3cde3fe3d and add it to our detection database. We initially classified it as adware, but a cursory analysis turned up suspicious network activity, which prompted us to dig deeper. It turned out the sample did far more than serve ads. In fact, its advertising functionality doesn’t even work; instead, it triggers an infection chain that delivers the ValleyRAT backdoor.

Malicious installer

The file the client shared with us turned out to be an installer that performed different actions depending on the two-letter suffix used in the file name, positioned just before the numeric string.

These actions are most likely designed to divert the user’s attention away from the sample’s malicious functionality. Regardless of the file name, the installer deploys a modified Chinese desktop wallpaper management tool called QN Wallpaper (hxxps://qnwallpaper[.]keansoft[.]cn/) and adds it to the registry’s autorun entries.

The original version of QN Wallpaper is genuine adware: on installation, it delivers bundled partner apps to the device and then displays ad banners to the user. In this case, however, the attackers use it to carry out DLL sideloading, a technique that allows malicious code to run under the guise of a signed process by way of a malicious DLL.

The QN Wallpaper modules, along with the malicious components, are unpacked to C:\Program Files\QNWallpaper\5.4.0.1662\<random string of letters and digits>. The following files are saved in that directory:

After unpacking, the installer uses the DisableAntiSpyware registry key to disable Windows Defender and then launches QnWallpaper.exe.

Disabling Windows Defender

DLL Sideloading via libcef.dll

QnWallpaper.exe has dependencies in libcef.dll, so this library gets loaded when the process starts. QnWallpaper.exe also launches QnwPlayer.exe, which likewise calls libcef.dll.

QnWallpaper and QnwPlayer won’t actually function correctly, because the functions exported from libcef.dll are put into an infinite sleep. However, in case that sleep is ever interrupted, the attackers have implemented a function that loads all the necessary functions from the original library into memory, provided it can locate that library on the system.

Example of an exported function

Loading functions from the original libcef.dll

The malicious functionality in libcef.dll is invoked by a call to DllMain, which runs automatically when the library is loaded. That said, alongside the original exports, the library also contains a function named RunDLL, which likewise initiates execution of the malicious code. QnWallpaper never calls this function. We suspect the attackers intended to invoke it manually via rundll32 or planned to use a separate executable for this purpose, one that wasn’t included in the package downloaded by the sample.

The RunDLL function

Running the malicious code

When the library is loaded, code runs that ensures QnWallpaper.exe persists at startup: it adds a file extension association and drops a file with the corresponding extension in C:\Documents and Settings\<username>\Start Menu\Programs\Startup\.

This is followed by a chain of wrapper functions whose main job is to call the next one. Execution eventually reaches the function that contains the actual malicious code. For convenience, we’ll refer to it as mw_entry.

Inside mw_entry, the malware checks two things:

• Whether the current user belongs to the Administrators group
• Which process the DLL is running inside

Checking for administrator privileges

If the user isn’t a member of the Administrators group, the program attempts to obtain administrator privileges by using the runas utility.

Relaunching the process to obtain administrator privileges

Once it has administrator privileges, the malicious code determines which process the DLL has been loaded into, and selects the payload accordingly:

• If the library is running inside QnWallpaper.exe, the payload is loaded from the PeLoader file.
  

  Encrypted payload

• If the library is running inside QnwPlayer.exe, the payload is loaded from libcef.dll resources.
  

  Retrieving the payload from a resource

Both payloads are AES-encrypted DLLs that contain the ValleyRAT backdoor. The only difference between them is their configuration, specifically, the C2 server addresses. After decryption, libcef.dll checks the magic signatures in the resulting PE file’s headers to confirm the sample is valid. If this check fails, the library releases its resources and takes no further action.

Validating the PE file headers after decryption

If the headers check out, libcef.dll loads the payload into the process’s memory space and hands control over to the backdoor by calling DllMain.

Calling DllMain

ValleyRAT

ValleyRAT begins its operation by parsing its configuration, which consists of key:value pairs concatenated into a single string. To obfuscate this configuration, the attackers wrote the string in reverse.

Obfuscated configuration

During parsing, the backdoor restores the correct character order and reads the key values one by one. The set of keys is the same regardless of which process the backdoor is running in.

Parsing the configuration

Some of the configuration fields are listed below:

The backdoor uses several techniques to protect its process. Some are configuration-dependent, while others are always applied:

• Injecting code into svchost to restart the process: a configurable option. The backdoor allocates memory inside the svchost process, injects code into it, and sets PAGE_NOACCESS permissions on the memory page containing the injected data. It then creates a suspended thread, waits 60 seconds, grants read, write, and execute permissions on the page, and resumes the thread.
  

  Injecting code into svchost

  The function injected into the process has a single job: restart the backdoor if its execution is interrupted for any reason.

  

  Injected function

• Marking its own process as critical (so that terminating it triggers a blue screen of death): a configurable option.
  

  Setting its own process as critical

• Restarting on an unhandled exception. This protection mechanism is always active, regardless of the backdoor’s configuration.
  

  Restarting on exceptions

The backdoor also has spyware functionality. While running, it tracks keystrokes and the currently focused window by using functions from the DirectInput8 library. It also captures clipboard contents. All collected data is saved to a file on disk.

Capturing clipboard data

If the ll key in the configuration is set to 1, ValleyRAT periodically checks for active windows belonging to applications that could be used to analyze processes or traffic. Window enumeration is done via the EnumWindows function, using the following callback:

Window name checks

After completing these checks, the backdoor collects system information, including:

• Host name
• Host IP addresses
• User idle time
• Detailed Windows version information (ProductName, EditionId, DisplayVersion)
• Number of CPU cores
• Free disk space
• Graphics adapter
• Currently focused window and its title
• System bitness
• Language settings
• Path to the system directory

On command, the backdoor can perform the actions typical of this malware category:

• Rebooting the computer
• Shutting down the computer
• Taking a screenshot
• Wiping logs
• Updating its C2 addresses
• Downloading additional modules
• Sending keylogger logs along with clipboard contents

Snippet of the command handler

Let’s take a closer look at the module-loading functionality. Upon receiving the corresponding command with a link from its operator, the backdoor downloads the file at that link and executes it. The download can come from either the C2 server or a third-party address.

The DownloadPeFile function is responsible for downloading a PE file

The DownloadAndExecute function calls DownloadPeFile, then launches the downloaded module

Additional modules can take the form of purpose-built dynamic libraries or shellcode. If the payload is shellcode, the backdoor uses process hollowing with svchost to launch the module.

Implementation of the process hollowing technique

If the module is a dynamic library, the backdoor loads the PE file into its own process, calls DllMain, and searches for a Main function among the exported functions. Once Main has been called, the library is unloaded from memory.

Calling DllMain after the backdoor loads the PE file

Targets and attribution

Over the course of 2026, we detected the ValleyRAT backdoor and its associated malware more than 100,000 times, with more than 1500 unique users affected, primarily in China and India.

This attack geography, combined with the use of the ValleyRAT backdoor, points to Silver Fox, a known operator of this malware family, as the likely group behind the campaign.

Conclusion

This case is a clear example of how adware and affiliate networks can turn out to be far more dangerous than they appear. ValleyRAT is a sophisticated backdoor capable of collecting sensitive data such as keystrokes and clipboard contents, taking screenshots, and delivering additional malicious modules. The attackers exploited a well-known adware application to run the backdoor under the guise of a signed process, which complicates detection.

Motivated by both cyberespionage and financial gain, Silver Fox targets organizations across multiple countries. To stay protected, organizations should keep employee cybersecurity awareness up to date and enforce clear policies on the use of third-party software on work devices.

For individual users, we recommend avoiding the installation of software with a questionable reputation, and, even more importantly, never adding such software to your security solutions’ exclusion lists.

IoC

MD5

07ddbbe2c71c45577a7a4fbcdba0df91
c24e99f9437feacaa63766a3cde3fe3d
8a626d844943da3456b044f38deae3a2

Network

103.45.66.18:441
103.45.66.18:442
103.45.66.18:443
192.253.225.173:6666
192.253.225.173:8888

Microsoft Threat Intelligence has observed a TerminalFix campaign, a variant of ClickFix, targeting organizations across multiple industries. The campaign uses compromised websites to display a fake Cloudflare CAPTCHA verification overlay that tricks users into copying and executing a malicious PowerShell command. While traditional ClickFix campaigns direct victims to the Windows Run dialog, TerminalFix campaigns apply the same technique but direct users to Windows Terminal or PowerShell instead, increasing the likelihood that complex, multi-line scripts execute successfully. Unlike earlier ClickFix variants that typically deliver a single infostealer, this TerminalFix campaign deploys a sophisticated multi-stage attack chain that combines DLL sideloading, steganographic payload extraction, extensive Active Directory reconnaissance, and a custom reverse-tunnel implant – giving the attacker persistent, network-level proxy access through the compromised host.

Once executed, the PowerShell command masquerades as a Cloudflare verification process while downloading a ZIP archive containing a legitimate binary (LockScreenContentServer.exe) and a malicious DLL (dui70.dll) used for sideloading. The sideloaded DLL drives an elaborate second stage: downloading payloads concealed inside PNG images using steganography, establishing dual persistence through Registry Run keys and scheduled tasks, conducting thorough domain reconnaissance—including domain trust enumeration, domain admin discovery, Active Directory user description harvesting, and targeted server ping sweeps—and ultimately deploying a Python-based reverse-tunnel C2 implant that tunnels arbitrary TCP traffic back through an encrypted WebSocket channel to attacker infrastructure.

This type of intrusion is particularly dangerous because it provides attackers with direct access to an organization’s internal network through the reverse tunnel. The observed reconnaissance and reverse-tunnel capability could enable an attacker to identify and reach additional systems from a compromised host. Microsoft did not observe the downstream actions described below in the analyzed chain. Organizations should treat affected devices as potential network pivot points and investigate for lateral movement and credential exposure. In the hands-on-keyboard phase that typically follows, attackers leverage this access to escalate privileges, disable security controls, exfiltrate sensitive data, and deploy ransomware across the organization. The combination of stealth techniques (DLL sideloading, steganography, hidden folders) and persistent network access make this TerminalFix campaign a serious threat to enterprise environments.

In this blog, we share our detailed analysis of the TerminalFix attack chain – from initial compromise through network tunneling—along with indicators of compromise, detection details, and hunting guidance to help defenders identify and respond to this threat.

Attack chain overview

The TerminalFix campaign follows a multi-stage attack chain that progresses from social engineering through payload delivery, persistence, reconnaissance, and ultimately network tunneling:

1. Initial access via compromised website – A compromised website displays a fake Cloudflare Turnstile CAPTCHA verification overlay. The user is instructed to copy and paste a “verification” command.

2. PowerShell execution – The pasted command runs a disguised PowerShell script that downloads a ZIP archive from attacker infrastructure, extracts it to C:\ProgramData, and silently launches a batch file.

3. DLL sideloading — The batch file executes LockScreenContentServer.exe, a signed legitimate binary, which automatically loads the co-located malicious dui70.dll.

4. Steganographic payload retrieval – The sideloaded DLL executes PowerShell that downloads PNG images from attacker domains, extracts embedded executables and DLL fragments hidden within pixel data, and reassembles them on disk.

5. Persistence – The malware establishes persistence through both HKCU\…\Run registry keys and scheduled tasks that re-execute LockScreenContentServer.exe every 60 minutes.

6. Reconnaissance – Extensive domain discovery is performed: domain trust enumeration, domain admin group membership, Active Directory computer and user enumeration, targeted server pinging, and system information collection in both English and Spanish locales.

7. Command execution loop – A persistent PowerShell file-watch loop monitors a text file for new commands, executes them via Invoke-Expression, and writes results to an output file-, creating a primitive but effective asynchronous command shell.

8. Reverse tunnel deployment – A Python runtime and a custom client.py tunneling implant are downloaded and launched via pythonw.exe with no visible window, establishing a reverse WebSocket tunnel to gitnow[.]dev:443 that gives the attacker full SOCKS-style TCP proxy access through the victim’s network.

Attack chain

1. Initial access: Fake CAPTCHA and the TerminalFix lure

The attack begins when a user visits a compromised website that displays a fake Cloudflare Turnstile verification overlay. The original page is briefly displayed before being replaced by a convincing Cloudflare Turnstile verification overlay. This overlay spoofs the Cloudflare CAPTCHA interface, complete with the Cloudflare logo, “Verify you are human” checkbox, and a spinner animation, tricking users into believing they must complete a verification step to access the site.

When the user interacts with the fake verification prompt, a malicious PowerShell command is silently copied to their clipboard. The on-screen instructions then guide the user to open Windows Terminal or PowerShell and paste the command. The command is carefully crafted to appear legitimate by printing reassuring Cloudflare-themed status messages in color-coded terminal output:

The command performs the following actions:

• Clears the terminal and prints a fake “Starting Cloudflare verification…” message in cyan color formatted
• Downloads a ZIP archive from the attacker’s infrastructure using a custom User-Agent header
• Extracts the archive to C:\ProgramData\f47f2a8c21c9df4e
• Launches a batch file (1.bat) that executes LockScreenContentServer.exe silently in the background
• Prints a convincing “I am not a robot – Cloudflare ID: f47f2a8c21c9df4e” confirmation message in green text

2. Payload delivery: DLL sideloading via LockScreenContentServer.exe

The downloaded ZIP archive (SHA-256: 18c2090e8a0ae0568af9b87e59eaf8270f23d2909600ed9db91a9444fd8b278f) contains two files:

LockScreenContentServer.exe is a legitimate, signed binary that has a static import dependency on dui70.dll, the Windows DirectUI Engine.

Here is the example view of LockScreenContentServer application importing dui70.dll function:

The attacker abuses this dependency by dropping a malicious dui70.dll alongside the executable. Because the Windows loader resolves the application directory before the System32 directory, the planted DLL is loaded in place of the legitimate one, a technique known as DLL sideloading (T1574.001). Execution therefore begins inside a trusted, signed process, allowing the attacker to inherit its reputation and evade controls that key on process identity.

The malicious dui70.dll embeds a heavily obfuscated payload in its resource section. On load, the DLL’s initialization path retrieves this resource, decodes it entirely in memory, and transfers execution to it, staging the next phase of the infection without ever writing the decoded payload to disk (Figures 5 and 6).

3. Second-stage delivery: Steganography and image-based payload extraction

Once sideloaded, the malicious DLL launches an elaborate PowerShell script that retrieves additional payloads concealed within PNG image files, a technique known as steganography. The script downloads three images from attacker-controlled domains, extracts binary data encoded in pixel values, and reassembles the components on disk.

Content domains

The script uses a failover mechanism across two domains:

Steganographic extraction

The Extract-RawFileFromImage function reads each pixel’s RGBA channels and reconstructs an embedded binary. The first 8 bytes encode the payload length as a 64-bit integer, and the remaining bytes contain the file data:

The script downloads three images via POST requests to the content domains, extracts the executable from the first image, extracts two halves of the DLL from the second and third images, and concatenates the DLL fragments:

Encoding payload data in PNG files can make file type and content inspection more difficult. Splitting the DLL across two images further obscures the complete payload in transit, the payloads aren’t recognizable as executables in transit, and splitting the DLL across two images further complicates detection. After extraction, the source images are deleted to reduce forensic artifacts.

4. Persistence mechanisms

The TerminalFix campaign establishes redundant persistence through two independent mechanisms, ensuring the payload survives reboots and re-executes on a recurring schedule. The dropped batch script takes the payload path as a command-line argument, validates that the file exists, and then configures both mechanisms under the same masquerading name LockScreenContentServer_MuODG5yBM chosen to blend in with the legitimate Windows Lock Screen component abused earlier in the chain.

Registry Run key

The malware creates a Run key entry with a randomized service-like name:

Scheduled task

A scheduled task ensures the malware re-executes every 60 minutes:

Folder hiding

The malware directory is hidden using system and hidden file attributes:

5. Reconnaissance and domain discovery

After establishing persistence, the sideloaded malware conducts extensive reconnaissance of the victim’s environment. This activity is consistent with a hands-on-keyboard operator or an automated pre-assessment script designed to evaluate whether the compromised host is a valuable target – particularly whether it is domain-joined and near high-value infrastructure.

System information collection

The attacker collects system metadata and the script includes English, Spanish, and German locale variants, indicating an attempt to operate across systems configured in multiple languages:

Active Directory enumeration

The malware performs domain trust discovery, domain admin enumeration, and Active Directory user and computer searches:

Infrastructure probing

The malware systematically pings named servers to map the internal network topology:

The observed names correspond to common infrastructure roles, including domain controllers, databases, backup, gateways, and mail systems. This probing could help an attacker identify accessible target systems for follow-on activity.

6. Asynchronous command execution loop

The malware deploys a persistent PowerShell file-watch loop that creates an asynchronous command-and-control channel through the local filesystem. This mechanism monitors a “watch” file for changes, executes its contents via Invoke-Expression, and writes results to an output file:

This loop provides the attacker with a way to execute arbitrary PowerShell commands by writing them to the watched text file. The output is captured to a separate file, which the attacker can read back through the reverse tunnel. This decoupled execution model allows the attacker to issue commands asynchronously and retrieve results at their convenience.

7. Reverse tunnel deployment: The custom Python-based tunneling implant

The most significant post-compromise capability observed is the deployment of a custom Python-based reverse-tunnel implant. The attacker brings their own interpreter: an unmodified, signed embeddable Python runtime pulled directly from the official python.org distribution. The malicious logic lives entirely in the accompanying client.py, giving the operator a portable, cross-version-tolerant execution environment that inherits the trust of a legitimate open-source runtime.

The deployment is orchestrated in PowerShell. It removes any prior install directory, extracts the implant kit, downloads the embeddable Python 3.14.5 archive over TLS 1.2, unpacks it into the same directory, and launches the tunnel with no visible window via pythonw.exe:

Tunneling implant analysis

The client.py script is a compact but full-featured reverse tunnel. It dials outbound to the C2 over TLS/443, upgrades the session to a WebSocket, and uses that channel to relay arbitrary TCP connections on behalf of the operator. On the wire, the traffic is indistinguishable from an ordinary encrypted web session to a single destination

The tunnel carries a lightweight custom protocol with eight message types spanning implant identification, connection setup, data relay, keepalive, and remote termination:

Turning the victim into a network pivot: The implant’s SOCKS5-style address parsing enables the C2 server to reach any host visible from the victim’s network. Combined with the reconnaissance data gathered earlier (domain controllers, SQL servers, backup servers, gateway), this turns the compromised machine into a full network pivot point:

The choice to launch with pythonw.exe (no visible window Python interpreter) means no console window is visible to the user. Combined with DEBUG = False by default and all logging going to stderr, the implant operates completely silently.

Mitigation and protection guidance

Microsoft recommends the following mitigations to reduce the impact of this threat:

• Restrict PowerShell and Run dialog execution – Use AppLocker, Application Control for Windows, or Group Policy to restrict PowerShell execution for standard users.
• Consider blocking or auditing the Windows Run dialog (Win+R) where it is not required for daily work.
• Monitor for DLL sideloading indicators — Alert on LockScreenContentServer.exe executing from non-standard paths (anything other than C:\Windows\SystemApps). Use the LockScreenContentServer.exe sideloading from non-standard paths advanced hunting query provided below to identify this activity across your environment.
• Educate users about ClickFix tactics – Train employees to recognize fake CAPTCHA verification pages that instruct them to paste commands into Terminal or the Run dialog.
• Investigate affected hosts thoroughly – Organizations that find indicators of this campaign should assume the attacker has network-level access through the compromised host. Credential rotation should be prioritized for any credentials accessible from the affected machine, including domain admin accounts if the host was domain-joined.
• Check your Microsoft 365 email filtering settings to ensure spoofed emails, spam, and emails with malware are blocked. Use Microsoft Defender for Office 365 for enhanced phishing protection and coverage against new threats and polymorphic variants. Configure Defender for Office 365 to recheck links on click and delete sent mail in response to newly acquired threat intelligence. Turn on safe attachments policies to check attachments to inbound email.
• Consider using enterprise-managed browsers, which provide multiple security features including security update requirements and data compliance policies.
• Block web pages from automatically running Flash plugins.
• Enable network protection and web protection in Microsoft Defender for Endpoint to safeguard against malicious sites and internet-based threats.
• Encourage users to use Microsoft Edge and other web browsers that support Microsoft Defender SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that host malware.
• Turn on cloud-delivered protection in Microsoft Defender Antivirus, or the equivalent for your antivirus product, to cover rapidly evolving attacker tools and techniques. Cloud-based machine learning protections block a majority of new and unknown variants.
• Enable PowerShell script block logging to detect and analyze obfuscated or encoded commands, providing visibility into malicious script execution that might otherwise evade traditional logging.
• Enforce use of PowerShell Constrained Language Mode where possible, in addition to use of execution policies such as setting AllSigned or RemoteSigned to help reduce the risk of malicious execution by ensuring only trusted, signed scripts are executed, adding a layer of control.
• Use Group Policy to deploy hardening configurations throughout your environment, if certain features are not necessary:
  • Create an App Control policy that prohibits the launch of native Windows binaries from Run. This can be accomplished by defining a rule based on the specific process that is launching binaries like PowerShell.
  • Configure Windows Terminal access and settings to warn users when the text they’re pasting contains multiple lines.
• Microsoft Defender XDR customers can also implement the following attack surface reduction rules to harden an environment against PowerShell techniques used by threat actors:
  • Block execution of potentially obfuscated scripts
  • Block executable files from running unless they meet a prevalence, age, or trusted list criterion
  • Block JavaScript or VBScript from launching downloaded executable content

Microsoft Defender XDR detections

Microsoft Defender XDR customers can refer to the list of applicable detections below. Microsoft Defender XDR coordinates detection, prevention, investigation, and response across endpoints, identities, email, and apps to provide integrated protection against attacks like the threat discussed in this blog.

Customers with provisioned access can also use Microsoft Security Copilot in Microsoft Defender to investigate and respond to incidents, hunt for threats, and protect their organization with relevant threat intelligence.

Microsoft Security Copilot

Security Copilot customers can use the standalone experience to create their own prompts or run prebuilt promptbooks to automate investigation and response tasks related to this threat. Useful promptbooks for this activity include Incident investigation, Microsoft User analysis, Threat actor profile, Threat Intelligence 360 report based on MDTI intelligence, and Vulnerability impact assessment. Some promptbooks require access to Microsoft Defender XDR, Microsoft Sentinel, or related Microsoft security plugins.

For this campaign, Security Copilot can help analysts summarize affected devices running LockScreenContentServer.exe from non-standard locations, trace the PowerShell steganography extraction chain, and build containment and credential rotation plans for affected domain-joined endpoints.

Threat intelligence reports

Microsoft customers can use Microsoft Defender XDR Threat analytics and related Microsoft threat intelligence reporting to stay current on the malicious activity, indicators, detection coverage, and recommended response actions associated with this compromise. These reports provide investigation context, protection guidance, and updated intelligence that security teams can use to prevent, mitigate, or respond to related activity in customer environments.

Advanced hunting queries

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

ClickFix PowerShell execution which executes payload

DeviceProcessEvents
| where InitiatingProcessFileName =~ "powershell.exe"
| where FileName =~ "cmd.exe" and ProcessCommandLine has_all (@"\ProgramData\", "1.bat", "LockScreenContentServer.exe")

LockScreenContentServer.exe sideloading from non-standard paths

DeviceImageLoadEvents
| where InitiatingProcessFileName =~ "LockScreenContentServer.exe"
| where FileName =~ "dui70.dll"
| extend path = tostring(parse_path(FolderPath).DirectoryPath)
| where path =~ InitiatingProcessFolderPath
| where not(path has_any (@"\Windows\System32", @"\Windows\SysWOW64", @"\winsxs\", @"\program files", @"\Windows Defender\", @"\Microsoft Security Client\", @"\Program Files\Windows", @"\Program Files\Microsoft", @"\ProgramData\Microsoft\", @"\Microsoft\Windows", @"\amd64_windows-defender-service", @"\Microsoft Defender for Endpoint\"))

Custom reverse tunnel implant execution

DeviceProcessEvents
| where FileName in~ ("pythonw.exe", "python.exe")
| where ProcessCommandLine has_all ("client.py", "--server", "--uuid", “cert.pem”, “gitnow.dev”)

Outbound connections to known C2 domains

DeviceNetworkEvents
| where RemoteUrl has_any ("gitnow.dev", "bestsocialmedianewspapper.com",
                            "offlineupdater.com")
| project Timestamp, DeviceName, RemoteUrl, RemotePort,
          InitiatingProcessFileName

MITRE ATT&CK Techniques observed

The following MITRE ATT&CK mappings reflect behaviors observed during this activity.

Initial Access

• T1189 Drive-by Compromise | A compromised website delivers a fake CAPTCHA overlay.

Execution

• T1059.001 Command and Scripting Interpreter: PowerShell | A malicious PowerShell command is pasted by the user into Terminal.
• T1204.002 User Execution: Malicious File | The user pastes and executes a clipboard-hijacked command.

Persistence

• T1547.001 Boot or Logon Autostart Execution: Registry Run Keys | An HKCU Run key is set to execute LockScreenContentServer.exe.
• T1053.005 Scheduled Task/Job: Scheduled Task | A scheduled task is created to execute every 60 minutes.

Defense Evasion

• T1574.002 Hijack Execution Flow: DLL Side-Loading | Malicious dui70.dll is side-loaded by the legitimate LockScreenContentServer.exe.
• T1027.003 Obfuscated Files or Information: Steganography | Payloads are hidden in PNG image RGBA pixel data.
• T1564.001 Hide Artifacts: Hidden Files and Directories | The attrib +h +s command is applied to the payload directory.
• T1036.005 Masquerading: Match Legitimate Name or Location | The DLL is named dui70.dll to match the legitimate Microsoft DUI framework.

Discovery

• T1018 Remote System Discovery | An ADSI query identifies Windows Server computers and performs a ping sweep.
• T1069.002 Permission Groups Discovery: Domain Groups | The net group “domain admins” /domain command is used for enumeration.
• T1482 Domain Trust Discovery | nltest /domain_trusts and /dclist: are used for domain enumeration.
• T1087.002 Account Discovery: Domain Account | An ADSI searcher enumerates user descriptions.
• T1082 System Information Discovery | systeminfo is used with multilingual findstr filters.

Command and Control

• T1572 Protocol Tunneling | A reverse WebSocket tunnel communicates over TLS with gitnow[.]dev:443.
• T1071.001 Application Layer Protocol: Web Protocols | Command-and-control communication occurs over HTTPS/WebSocket.
• T1105 Ingress Tool Transfer | A Python runtime and implant kit are downloaded and extracted.

Indicators of Compromise (IOCs)

File indicators

Network indicators

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

To get notified about new publications and to join discussions on social media, follow us on LinkedIn, X (formerly Twitter), and Bluesky.

To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.

Review our documentation to learn more about our real-time protection capabilities and see how to enable them within your organization.  

• Learn more about securing Copilot Studio agents with Microsoft Defender 
• Evaluate your AI readiness with our latest Zero Trust for AI workshop.
• Microsoft 365 Copilot AI security documentation
• How Microsoft discovers and mitigates evolving attacks against AI guardrails

The post TerminalFix campaign deploys a reverse tunnel through multistage intrusion appeared first on Microsoft Security Blog.

The vulnerability landscape shifted significantly in Q2 2026. First, the number of registered CVEs reached an unprecedented level. This is driven primarily by the widespread adoption of AI, both for application development and search for security flaws. This resulted in entire new classes of vulnerabilities emerging, particularly in the Linux networking subsystem.

Second, security researchers have been publishing exploits for unpatched vulnerabilities more frequently. Publications like these can generate significant fallout, since they potentially open the door for attackers to target unprotected systems.

Statistics on registered vulnerabilities

This section provides statistical data on registered vulnerabilities. The data comes from Kaspersky’s vulnerability knowledge base, which draws on the CVE database as well as the Russian BDU database and GitHub Advisory (GHSA). As a result, the figures for previous reporting periods may differ from those published in earlier reports.

We examine the number of registered vulnerabilities for each month over the last five years. As the chart below shows, this number continues to surge, a trend reflected across all the databases we track. It’s driven primarily by the widespread adoption of AI tools: as we predicted in our previous report, these tools have played a major role in the discovery of vulnerabilities in third-party software. Meanwhile, these tools often contain security issues of their own. For example, OpenClaw, a popular AI project, ranked 12th among those with the highest number of vulnerabilities discovered and published in Q2, with over 200 CVEs registered during the reporting period. Finally, AI development tools are also contributing to the vulnerability landscape, since the quality of the code they produce can vary widely. Therefore, the rate at which new vulnerabilities are discovered will inevitably keep growing.

Total published vulnerabilities per month from 2022 through 2026 (download)

Next, we analyze the number of new critical vulnerabilities (CVSS > 9.0) over the same period.

Total critical vulnerabilities published per month from 2022 through 2026 (download)

As the chart shows, the number of published critical vulnerabilities jumped sharply in Q2. This is because using AI for vulnerability research makes it possible to analyze massive amounts of previously unexamined code, uncover new attack surfaces, and identify entire classes of vulnerabilities that have gone unnoticed for decades. In particular, AI was used to find a series of Dirty Frag vulnerabilities in the Linux kernel.

Exploitation statistics

This section presents statistics on vulnerability exploitation for Q2 2026. The data draws on open sources and our telemetry.

Windows and Linux vulnerability exploitation

Q2 2026 saw a new precedent in the publication of vulnerabilities in Windows components and exploits for these: researchers no longer waiting for CVE registration, let alone patches. A case in point: a researcher who goes by Nightmare Eclipse (also known as Chaotic Eclipse) published a list of new “named” vulnerabilities across various Windows subsystems. At the time the technical details were published, none of the vulnerabilities had been assigned a CVE identifier:

• BlueHammer: a local privilege escalation vulnerability in Windows Defender. During signature database updates, a time-of-check to time-of-use (TOCTOU) race condition occurs, allowing an attacker to substitute the directory where temporary update files are written. The researcher published a fully functional exploit for the vulnerability.
• RedSun: another logical vulnerability in Windows Defender with a working exploit. Suspicious and malicious files marked as “cloud” can be overwritten or restored to their original directory with elevated privileges. The exploit incorporates fragments of algorithms that make it possible to leverage various logical vulnerabilities in Windows, effectively combining a large number of popular exploitation techniques.
• YellowKey: a vulnerability that lets the user bypass BitLocker full-disk encryption and access system data through the Windows Recovery Environment (WinRE). A fully functional exploit was also published.
• GreenPlasma: a vulnerability that enables system object injection via the CTF loader for the Collaborative Translation Framework (CTFMON) service in Windows. The original publication included an exploit with limited functionality.
• RoguePlanet: yet another Windows Defender vulnerability that, like BlueHammer, stems from a TOCTOU issue, this time in the engine responsible for real-time system scanning. The published exploit uses the vulnerability to overwrite the system file wermgr.exe with a malicious one.
• UnDefend: another vulnerability in the Windows Defender service. This time, the exploit causes a denial of service and blocks updates.

Even though such cases remain isolated for now, we believe they’ll grow into a full-fledged trend. Early publication of exploits gives attackers an advantage over software developers, who are left with no time to fix the issues.

Veteran vulnerabilities in Windows software also remain relevant. These are the ones our solutions most frequently detect exploits for:

• CVE-2018-0802: a remote code execution (RCE) vulnerability in the Equation Editor component
• CVE-2017-11882: another RCE vulnerability also affecting Equation Editor
• CVE-2017-0199: a vulnerability in Microsoft Office and WordPad that allows an attacker to gain control over the system
• CVE-2023-38831: a vulnerability in WinRAR that involves improper handling of objects within an archive
• CVE-2025-6218 (formerly ZDI-CAN-27198): another WinRAR vulnerability allowing the specification of relative paths to extract files into arbitrary directories, potentially leading to malicious command execution
• CVE-2025-8088: a vulnerability similar in exploitation method to CVE-2025-6218. The attackers used NTFS Streams to circumvent controls on the directory into which files are being unpacked

The vulnerabilities listed here can be leveraged to gain initial access to a vulnerable system and for privilege escalation. This underscores the critical importance of timely software updates.

That said, the number of Windows users who encountered exploits declined slightly in Q2, hitting an 18-month low.

Dynamics of the number of Windows users encountering exploits, Q1 2025 – Q2 2026. The number of users who encountered exploits in Q1 2025 is taken as 100% (download)

Linux also hit a rough patch in Q2 2026. Specifically, the period saw the disclosure of the Dirty Frag family of vulnerabilities, which lets an attacker reliably escalate privileges within the operating system.

All the vulnerabilities published in Q2 2026 were, in one way or another, related to the Linux caching subsystem. Here are the ones being most actively exploited:

• CVE-2026-31431 (Copy Fail): a local privilege escalation vulnerability in the Linux kernel that lets an unprivileged user modify the page cache and gain root privileges. Especially dangerous for cloud and containerized environments
• CVE-2026-43284, CVE-2026-43500 (Dirty Frag): a family of vulnerabilities in the Linux networking subsystem (IPsec ESP and RxRPC) that lets a local user overwrite the page cache and escalate privileges to root
• CVE-2026-46300 (Fragnesia): a local privilege escalation vulnerability in the Linux kernel related to packet fragment handling and the page cache mechanism. It lets an unprivileged user gain root privileges and is also classified as part of the Dirty Frag family
• CVE-2026-31635 (DirtyDecrypt): a Linux kernel vulnerability that lets a local attacker escalate privileges due to improper handling of decryption operations and page cache data modification
• CVE-2026-43494 (PinTheft): a Linux kernel vulnerability that lets a local user gain elevated privileges due to errors in the memory page pinning mechanism
• CVE-2026-46331 (pedit COW): a vulnerability in the Linux kernel’s traffic control subsystem (tc-pedit) that exploits a flaw in copy-on-write to modify the page cache and subsequently escalate privileges to root

The vulnerabilities described above were quickly embraced by attackers. At the same time, our solutions continue to detect exploitation attempts targeting older vulnerabilities as well:

• CVE-2022-0847: a vulnerability known as Dirty Pipe, which enables privilege escalation and the hijacking of running applications
• CVE-2019-13272: a vulnerability caused by improper handling of privilege inheritance, which can be exploited to achieve privilege escalation
• CVE-2021-22555: a heap out-of-bounds write vulnerability in the Netfilter kernel subsystem
• CVE-2023-32233: another Netfilter subsystem vulnerability that allows for Use-After-Free conditions and privilege escalation through improper processing of network requests

Dynamics of the number of Linux users encountering exploits, Q1 2025 – Q2 2026. The number of users who encountered exploits in Q1 2025 is taken as 100% (download)

In Q2 2026, the number of Linux users who encountered exploits declined slightly compared to Q1. Given that a significant share of new vulnerabilities are tied to the operating system’s caching subsystem, we recommend installing patches as quickly as possible, or disabling vulnerable kernel modules if patching isn’t an option.

Most common published exploits

The distribution of published exploits by software type in Q2 2026 includes categories that haven’t appeared in the sample for a long time. For instance, we’re once again seeing exploits targeting SharePoint. It’s worth noting that while several vulnerability write-ups for Exchange and SharePoint were published during the quarter, most turned out to be fake, AI-generated research. While the articles and exploit source code themselves look fairly polished, they describe nonexistent problems in the software or its components — often close to genuinely vulnerable mechanisms — in order to mislead researchers. This type of attack is aimed at increasing the time it takes to detect real vulnerabilities. In some cases, the description of a nonexistent vulnerability came bundled with completely unrelated malware.

Distribution of published exploits by platform, Q1 2026 (download)

Distribution of published exploits by platform, Q2 2026 (download)

Vulnerability exploitation in APT attacks

We analyzed which vulnerabilities were exploited in APT attacks during Q2 2026. The rankings provided below include data based on our telemetry, research, and open sources.

TOP 10 vulnerabilities exploited in APT attacks, Q2 2026 (download)

In Q2 2026, a trend emerged in APT attacks toward exploiting new vulnerabilities right from the moment they’re published. As before, we’re also seeing a large number of zero-day vulnerabilities. The Langflow vulnerability deserves particular attention: it’s one of the first cases of an APT group exploiting AI technology, which many organizations are only just beginning to integrate. Because most of this tech is proprietary, it has a considerable number of security blind spots. Therefore, given the growing number of AI-based automation tools, we strongly recommend going beyond the usual patching and developing secure procedures for credential use and sensitive data handling in systems that rely on agents and LLMs.

C2 frameworks

In this section, we examine the most popular C2 frameworks used by APT groups and analyze the vulnerabilities targeted by the exploits that interacted with C2 agents in APT attacks.

The chart below shows the frequency of known C2 framework usage in attacks during Q2 2026, according to open sources.

TOP 10 C2 frameworks used by APTs to compromise user systems, Q2 2026 (download)

Sliver, Havoc, AdaptixC2, and Metasploit remain the most widely used C2 frameworks. After studying open sources and analyzing samples of malicious C2 agents that contained exploits, we determined that the following vulnerabilities were utilized in APT attacks involving the C2 frameworks mentioned above:

• CVE-2026-35273: a vulnerability in Oracle PeopleSoft PeopleTools that security vendors classify as server-side request forgery (SSRF). The details of the vulnerability have never been disclosed, although some research covers the post-exploitation steps
• CVE-2023-46604: an insecure deserialization vulnerability in Apache ActiveMQ that allows arbitrary code execution in the context of the service process
• CVE-2024-12356 and CVE-2026-1731: command injection vulnerabilities in BeyondTrust software that allow an attacker to send malicious commands even without system authentication
• CVE-2023-36884: a vulnerability in the Windows Search component that allows commands to be run on the system, bypassing the mark-of-the-web (MoTW) mechanism
• CVE-2025-53770: an insecure deserialization vulnerability in Microsoft SharePoint that allows for unauthenticated command execution on the server
• CVE-2025-8088 and CVE-2025-6218: similar directory traversal vulnerabilities in WinRAR that allow files to be extracted from an archive to a predetermined path, potentially without the archiving utility displaying any alerts to the user

These vulnerabilities show that attackers used them for initial access and privilege escalation on vulnerable systems, setting the stage for launching a C2 agent. They include both zero-day vulnerabilities and fairly well-known security issues.

LLM/AI tool vulnerabilities

This section analyzes data published in Kaspersky’s vulnerability knowledge base. We reviewed the Q2 2026 version of the knowledge base.

As mentioned above, AI tools, plugins, and technologies have proven fairly effective at automating the search for problematic code and anomalous behavior. The high speed at which new vulnerabilities are being discovered has naturally created a need to fix them just as quickly. AI is often used for this too, which increases the volume of code being generated. However, neither code written without human involvement nor AI-generated advice is always correct.

The chart below covers registered vulnerabilities in AI tools for 2025–2026.

Number of published vulnerabilities in LLMs, AI tools, and plugins with similar functionality, 2025–2026 (download)

As the charts show, AI tools are racking up a substantial number of registered vulnerabilities, and that number keeps growing quarter over quarter. It’s also worth looking at how AI tool vulnerabilities break down by type, according to the CWE system:

TOP 6 vulnerability types in products that implement or use AI/LLM logic, 2025–2026

Interestingly, vulnerabilities of an undetermined type have ranked first in every quarter since the start of 2025. Traditionally-made software has the same issue, and it doesn’t look like the growing number of AI tools will fix it. It’s also notable that the list includes classes CWE developers themselves don’t recommend using for vulnerability classification, since they lump together a whole range of more specific types. CWE-284 is an example of this.

Looking at the most common classes, the key issues found in AI-related software can be summed up as follows:

• Inadequate access control over critical system objects
• Improper implementation of authentication and authorization mechanisms
• Injections

It’s worth noting that injection-related vulnerabilities were relatively rare before AI agents took off (previously, they mostly affected web apps). Recently, though, these security issues have become relevant again.

Looking back at a year and a half of the AI boom, one conclusion stands out regarding registered vulnerabilities: AI tool developers are more focused on expanding functionality than on security. This is worth keeping in mind when using these tools. Let’s look at the projects and applications that either integrated AI tools or offered them as the core product. Below is a list of the those with the highest number of registered vulnerabilities for 2025–2026.

TOP AI/LLM-related projects by number of published vulnerabilities, 2025–2026 (download)

Notable vulnerabilities

This section highlights the most significant vulnerabilities published in Q2 2026 that have publicly available descriptions. Since the above already covers several significant vulnerabilities published during the reporting period, this section consists mainly of LLM/AI tool vulnerabilities.

CVE-2026-25253: a gatewayUrl vulnerability in OpenClaw

The issue stems from the fact that the OpenClaw user interface trusts the value of the gatewayUrl parameter passed in the URL and automatically establishes a WebSocket connection to the specified address. During this connection process, it sends an authentication token without any additional user confirmation.

The attack algorithm exploiting this vulnerability works as follows:

1. The application obtains a critical connection address from an external source (the gatewayUrl URL parameter), which is controlled by the attacker.
2. There is no validation before use.
3. The client automatically initiates a connection to the address specified in the parameter, which belongs to the attacker.
4. While connected, the application sends credentials (an access token) to the specified address.

If the attacker obtains a valid token, the consequences depend on that token’s level of access within the system. In general, this could lead to:

• User session compromise
• Execution of operations on the user’s behalf
• Modification of the AI agent configuration
• Unauthorized access to tools and resources connected to the agent
• Under certain OpenClaw configurations, further compromise of the host running the agent

It’s worth noting that the risk of exploitation arises from a combination of several factors: the automatic connection and token transmission, the lack of address trust verification, and the high privileges granted to the local AI agent.

CVE-2026-41948: a path traversal vulnerability in the Dify AI platform

The vulnerability lets an authenticated user craft a request that enables the application to escape its permitted tenant and gain access to internal REST APIs that weren’t meant for that user. The root cause is insufficient normalization and validation of the URL path before it’s passed to the internal service.

Depending on the Dify configuration, the consequences can include:

• Unauthorized access to internal service interfaces
• Breach of isolation between workspaces
• Exposure of internal service information
• Conditions favorable to further attacks when combined with other vulnerabilities

The use of Dify in enterprise AI platforms is particularly risky, since internal services there tend to hold elevated privileges.

CVE-2026-45386: an improper access control vulnerability in Open WebUI

In Open WebUI, pin/unpin operations on messages are write operations, since they modify that message’s metadata (is_pinned, pinned_by, pinned_at). In vulnerable versions, however, before performing these actions, the API only checked for read access to the channel (a chat between a user or group and the AI) containing the message, not permission to modify its content. As a result, a user with a role limited to viewing messages could still change a message’s pinned status.

The vulnerability’s mechanism works as follows:

1. The user initiates an action that changes the state of an object.
2. The application treats this action as a regular read request.
3. Only channel view permission is checked.
4. The application performs a write without verifying the required user authorization.

This violates one of the fundamental principles of access control models — namely, that any operation that changes the state of data must be checked for the appropriate write or moderation permissions, regardless of whether the object itself is readable.

Although the vulnerability doesn’t lead to arbitrary code execution or compromise of sensitive data, it can affect data integrity and collaborative workflows. Potential consequences of exploitation include unauthorized pinning or unpinning of messages, disruption of channel moderators’ and administrators’ activities, changes to the display order of important information, and even the potential spread of false or misleading information by altering the channel containing a pinned message.

Open WebUI is widely used as an interface for interacting with local and enterprise LLMs. In these systems, pinned messages often contain important instructions, announcements, or tips for users. The ability to modify them with minimal privileges can disrupt collaborative workflows, cause confusion, and undermine trust in information published by administrators and moderators.

CVE-2026-45501: a vulnerability in Microsoft Exchange

The vulnerability stems from improper neutralization of user input when generating Exchange web pages. As a result, the browser may interpret specially crafted data as active content instead of plain text.

Although Microsoft categorizes the potential impact of exploiting this vulnerability as spoofing, flaws like this can lead to alteration of displayed content, imitation of trusted interfaces, actions on behalf of the user within an active session, and abuse of user trust.

It’s worth noting that issues like this are still relevant in modern software, given that mechanisms like Content Security Policy and various parsers were specifically created to help developers neutralize dangerous parts of user page content.

Conclusion and advice

Q2 brought the first significant results of AI automation adoption in software development and vulnerability hunting tools. This research shows that beyond traditional patch management, organizations now need real-time monitoring of systems and access controls, since infrastructure and everyday applications now contain far more AI functionality that could lead to compromise.

Accordingly, besides quickly detecting infrastructure vulnerabilities and managing security patches, modern enterprise-grade security solutions need to provide a broad range of preventive measures for tracking the overall health of systems and workstations. Kaspersky Next meets these requirements by combining proactive mechanisms with the ability to respond promptly to emerging threats.

While monitoring Android threats in June 2026, we discovered a new piece of Android malware. What struck us as unusual was that it installed like an ordinary user app yet made no attempt to disguise itself as legitimate software: it had no user interface at all. This led us to suspect the app might be reaching users’ devices without their knowledge. Further investigation confirmed that hypothesis and allowed us to reconstruct the entire infection chain.

Key findings:

• We identified new Android malware: a multi-stage downloader whose ultimate purpose is ad fraud and creation of a proxy botnet.
• The malware spread through the built-in updaters of Android-based automotive head unit firmware. This is the first documented case of malware found on a car head unit with an infection chain specific to that type of device.
• We attribute this activity, with high confidence, to the MoYu Group, an actor linked to the BADBOX botnet.

Kaspersky solutions detect the threats described below under the following detection names:

• HEUR:Trojan-Dropper.AndroidOS.Agent.vu
• HEUR:Trojan-Downloader.AndroidOS.Agent.ov
• HEUR:Trojan-Proxy.AndroidOS.Zhima.*
• HEUR:Trojan.AndroidOS.Vo1d.*

Head unit firmware overview

A head unit is a system that combines multimedia functions with partial control over certain vehicle functions. Head units may come as part of a car’s factory equipment or as an aftermarket upgrade. The main attack vectors for these systems are compromise via physical access and vulnerabilities in the head unit’s OS or components, both of which we’ve covered previously.

In some cases, head units run on Android, primarily because it’s convenient for manufacturers: Android’s source code already accounts for use cases within automotive head units. Android also allows manufacturers to add their own system applications during the build process, which they can use for a range of purposes: customizing the UI, adding system components tailored to the vendor’s needs, and more.

Most apps developed for Android devices can also run on an Android-based head unit, and that is true for malware as well. That said, it’s hard to imagine certain categories of smartphone-targeted malware being used to attack a head unit. Banking Trojans are a good example: since mobile banking is used almost exclusively on smartphones, infecting a head unit with a banking Trojan would be a waste of the attacker’s resources.

It’s worth noting that head units often include SIM card slots and can connect to the internet, enabling features like navigation and software updates. Since a head unit typically holds nothing of value to an attacker, one of the more likely attack scenarios using “classic” Android malware is infecting the device to recruit it into a botnet – similar to attacks on IoT devices.

During our research, we found exactly that kind of malware. The design of firmware for DoFun head units enabled attackers to distribute malware. We notified the vendor about the distribution scheme, and they subsequently reported fixing the security issues.

Below is the entire infection chain:

Head unit infection scheme

Let’s look at exactly how these head units became infected.

The TWCore app

TWCore is a legitimate system application responsible for collecting analytics data and updating the head unit software. Let’s take a closer look at how the update function works.

The process is fairly simple. An MQTT message broker hosted on the subdomain cardoor[.]cn sends a message containing information about the APK files that need to be downloaded and installed on the head unit. Notably, the object describing this message includes an installNotExists field, a Boolean flag that can be set to true or false. This flag allows TWCore to install apps that weren’t originally present on the device.

TWCore only checks whether an app is already installed on the device when installNotExists = false

The APK file is downloaded to <TWCore external cache dir>/push/apk/ for installation.

The path TWCore uses to download APK files

Our telemetry revealed previously unknown malware at these file paths. On top of that, our data indicates that in every observed case, the malware was installed by an app with the package name com.tw.core, which matches the TWCore package name.

Next, we’ll break down the malware installed by TWCore: the JarService dropper.

Stage 1: the JarService dropper

As mentioned earlier, JarService is a small dropper app with no UI of any kind. It decrypts data stored as encrypted blocks within the Trojan’s code. Each block is XOR-encrypted with a single-byte key that shifts linearly from block to block. The decrypted data contains serialized information about the payload version and entry point, along with the malware’s own code for further loading.

Decrypting and deserializing information about the stage 2 payload

In the version of JarService we analyzed, the entry point for the next-stage payload was the wa method of the com.c.j.qbh class.

Stage 2: the loader

This stage’s payload is a malicious loader. Its code contains encrypted strings that are later used as class names to execute the stage 3 payload using the reflection mechanism. The loader sends implant information to one of the attackers’ servers via a POST request. Example of a request to the C2 server:

{
    "userId": "REDACTED",
    "dexVersion": "1.7",
    "dexType": 1,
    "channelId": "2039",
    "packageName": "com.tw.jar1",
    "appVersion": 12,
    "appName": "JarService"
}

In response to the POST request, the C2 server returns a link for downloading the stage 3 payload. An example of a C2 response is shown below.

{
    "code": 200,
    "data": {
        "dexUrl": "hxxp://144.217.243[.]201/vr34der34/dex3.68.png",
        "dexVersion": 3.680,
        "status": 0
    }
}

The Trojan uses the link in the dexUrl field of the data object to download serialized data for loading the next stage. This data begins with a single-byte integer, a key used to decrypt the strings in the loader’s code. Immediately following this number is a four-byte floating-point value used to XOR-decrypt the stage 3 payload, which itself is located after these keys.

Decrypting the stage 3 payload

In the decrypted payload, the entry point is the init method of the com.ast.sdk.BillingMain class, shown in the screenshot below.

Entry point of the stage 3 payload

While analyzing this stage, we noticed that the download link for the next-stage payload includes a version number. We decided to try other version numbers to retrieve different payload versions, and ultimately obtained seven distinct variants, which we list under “Indicators of Compromise” at the end of this report. The earliest version, numbered 3.57, uses a different decoding algorithm than the one described above. This may indicate that an earlier version of the infection chain used a different loader between JarService and the stage 3 payload.

Stage 3: clicker / reverse proxy loader

In this stage, the malware sends a POST request to /cpc/api/task every 90 minutes by default, containing information about the infected device (display resolution, device model, the SSID of the connected Wi-Fi network, MAC address, and so on) along with the Trojan’s configuration version. If the configuration is outdated, the C2 server returns an updated configuration containing new C2 addresses and new paths for sending HTTP requests. An example of a response is shown below. Note that at the time of our research, the most up-to-date configuration version was 3.82.

{
    "code": 100,
    "data": {
        "configVersion": 3.820,
        "hosts": ["hxxp://t2.kshahnd[.]sbs", "hxxp://t2.mdsjhd[.]sbs", "hxxp://t2.nmnsny[.]sbs", "hxxps://t2.nmnsny[.]sbs"],
        "interval": 5500000,
        "reportApi": "/cpc/api/report",
        "tagName": "config",
        "taskApi": "/cpc/api/task",
        "updates": ["hxxp://a2.kshahnd[.]sbs", "hxxp://a2.mdsjhd[.]sbs", "hxxp://a2.nmnsny[.]sbs", "hxxps://a2.nmnsny[.]sbs"],
        "vn": 1.010
    }
}

If the configuration version doesn’t need updating, the C2 server instead returns integer command identifiers, which the attackers refer to as productId. The Trojan maps each identifier to command information, which it stores as a serialized JSON object using the SharedPreferences API. Each identifier also has its own version, expressed as a UNIX timestamp. If the C2 response includes an unknown productId or one whose version is outdated, the malware sends a GET request to the attackers’ server at /cpc/api/xml to retrieve the command contents for all such identifiers. The C2 server responds with command information for each unknown identifier. An example of a response is shown below.

{
    "code": 200,
    "data": [{
        "productId": 979,
        "script": "{\n  \"loadType\": 1,\n  \"reload\": true,\n  \"method\": \"start\",\n  \"url2\": \"hxxp://144.217.243[.]201/vr34der34/sh65.io\",\n  \"md52\": \"de77c3303e93c9450424759f1741441c\",\n  \"name\": \"zhima\",\n  \"className\": \"com.miyc.transfer.Client\",\n  \"thread\": true,\n  \"tagName\": \"loadlib2\",\n  \"params\": [\n    {\n      \"type\": \"Context\"\n    },\n    {\n      \"type\": \"String\",\n      \"value\": \"107.151.248[.]132\"\n    },\n    {\n      \"type\": \"String\",\n      \"value\": \"1002\"\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 1337\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 7777\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 8888\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 15000\n    }\n  ],\n  \"url\": \"hxxp://144.217.243[.]201/vr34der34/sh65.io\",\n  \"md5\": \"de77c3303e93c9450424759f1741441c\"\n}",
        "version": 1778650942
    }, {
        "productId": 1019,
        "script": "{\n  \"loadType\": 1,\n  \"reload\": true,\n  \"method\": \"start\",\n  \"url2\": \"hxxp://144.217.243[.]201/vr34der34/sh65.io\",\n  \"md52\": \"de77c3303e93c9450424759f1741441c\",\n  \"name\": \"zhima\",\n  \"className\": \"com.miyc.transfer.Client\",\n  \"thread\": true,\n  \"tagName\": \"loadlib2\",\n  \"params\": [\n    {\n      \"type\": \"Context\"\n    },\n    {\n      \"type\": \"String\",\n      \"value\": \"128.14.210[.]58\"\n    },\n    {\n      \"type\": \"String\",\n      \"value\": \"1002\"\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 9999\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 7777\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 8888\n    },\n    {\n      \"type\": \"int\",\n      \"value\": 15000\n    }\n  ],\n  \"url\": \"hxxp://144.217.243[.]201/vr34der34/sh65.io\",\n  \"md5\": \"de77c3303e93c9450424759f1741441c\"\n}",
        "version": 1766001509
    }, {
        "productId": 3505,
        "script": "{\n\"tagName\":\"http\",\n\"url\":\"hxxps://api.kookjar[.]com/sayhi?channel=daihai&uuid={get_uuid_10}\"\n}",
        "version": 1776656317
    }],
    "msg": ""
}

The command information includes a tagName field, which is the command name. The code maps each name to the corresponding class responsible for executing it.

List of executable commands

At the time of our research, the attackers had implemented nine commands. The table below lists command names, brief descriptions, and arguments. The functionality of these commands suggests that the malware can be used to display ads, commit ad fraud (serving as a clicker), and download additional malicious code.

However, attackers use only a relatively small subset of these commands in real-world attacks. As shown in the example C2 response above, at the time of publishing this report the attackers were using the loadlib2 and http commands. The payload downloaded via the loadlib2 command is a reverse proxy module named “zhima”, which researchers from the Nokia Deepfield Emergency Response Team independently discovered in TV set-top boxes around the same time as we did and also described in their report. This confirms that the attackers’ ultimate goal is building a proxy botnet.

While investigating this stage of the attack chain, we noticed that the zhima download link also included a version number. As with the previous stage, we tried other possible version numbers and found eight variants of the zhima module, the earliest of which was version 57. The complete list of identified zhima modules is provided under “Indicators of Compromise” below.

Attribution

While analyzing the complete infection chain, we noticed that the stage 2 loader created a thread with the meaningful name mosdk-host-loader. We decided to investigate what mosdk referred to in that name. This led us to a malicious app installed on various TV set-top boxes with the package name com.abc.nexus (3AD4BF5A86D26FFBF09CAE42AF330A98). It consists of several components (including a dropper similar to JarService), each used by the attackers to covertly monetize the device’s computing power. Each malicious component in the app corresponds to its own service, and the service containing the launch code for the JarService-like dropper is named AdmoyuService. In light of this and the name of the malicious thread found in the payload code, we concluded that moyu in the service name referred to MoYu Group, one of the actors linked to the BADBOX malware platform, which had been described by researchers at HUMAN. This assessment is further supported by extensive overlap between the malware’s network infrastructure and that of MoYu Group, which was independently identified by researchers from the Nokia Deepfield Emergency Response Team around the same time as our own research. Based on these similar naming patterns and prominent infrastructure overlap between the activity of MoYu Group and the attacks described in this report, we attribute it to the same actor with high confidence.

While investigating the malware downloaded by TWCore, we noticed that the domain admin.uipoxy[.]com resolved to the IP address 128.14.210[.]58, one of the C2 servers for the zhima reverse proxy module. It appears that the URL hxxp://admin.uipoxy[.]com/proxy/u/login hosts the zhima admin panel. Interestingly, this panel allows anyone to register as long as they have a valid invite code.

The malware operator registration page

During registration, users are prompted to review the terms of use and privacy policy. Both documents are hosted on links under the pxyedge[.]com domain, which belongs to PXYEDGE, a vendor specializing in the sale of residential proxies.

On the registration page hosted at admin.uipoxy[.]com, we also found the string copyright © 2020 proxyforu[.]com all rights reserved, which linked to hxxps://proxyforu[.]com, the website of ProxyForU, another vendor of residential proxy services.

We found several similarities in the authentication APIs across all of these sites:

• The sign-in page was hosted on an admin.* subdomain.
• The sign-in page was located at /proxy/u/login.
• The signup page was located at /proxy/register?channelKey=<invitation code>.

Based on this, we believe these services are connected to MoYu Group.

Conclusion

Despite efforts by cybersecurity professionals and law enforcement to shut down the BADBOX botnet, individual actors linked to it continue their malicious activity, infecting devices worldwide. Delivery methods for this kind of malware vary widely, from downloads via pre-installed backdoors to infected builds of IPTV apps. The case examined here demonstrates an even more sophisticated delivery method: distribution through the legitimate update functionality of a system application. Attackers are also actively expanding into new platforms. This malware is the first known malicious app targeting head units, which means these platforms now require protection against malware as well.

Indicators of compromise

Stage 1: JarService

ba27951b4ee1c341f4415d033369ecd3
d63bacd6d6709dd68a10ef9d374c7835
6c2e34b30da42085240ede53ab6107d4
8b5e513144a6138a966ea59e68bf9da2
e119845877089d6f4b0a70dc7388f316

Stage 2: loader

e9f3a0dab6949ce2cddab9e0aa80ae1a

Stage 3: loader/clicker

0fbaa7092204f4b1494e0b840b014774
1dcf031c40ce456b6a36a00b0acf3d11
44b6b213a6a3f299eaf88e078de95ecb
67dc78e544ebce16b85dc7c195dfbc58
9642ae619b3165d23c6349002d1abe24
b067d5b0dbecbd6498bcdfba45dba77e
f0e3f7eba2cde91e2dedb921bab47422

zhima module

412e9243f2981bbea3894254d105b3b8
71ab5517f71866279d0d87d37f2ae320
89ef78f716a75964539f2db6520be362
a4223ce4288a230d1e6c3ff2c7639045
bd4d81cd27125ad3d9a114922d468499
c6bfb1643ac7474ed8a7b4f96a187fdb
de77c3303e93c9450424759f1741441c
f8cf8c23ff597700d471fb7767df8bac

Domains and IP addresses

xmsae[.]sbs
ishano456[.]sbs
xshaon123[.]sbs
kshahnd[.]sbs
mdsjhd[.]sbs
nmnsny[.]sbs
kookjar[.]com
ty54fgd435[.]my
ue886578433[.]online
ty4523[.]space
144.217.243[.]201
107.151.248[.]132
128.14.210[.]58

Addresses used to download JarService

hxxp://ovcloudcontrol.cdn.cardoor[.]cn/upgrade/2026-06-08/bd80bd3c3d0e4bf6b5b4a825650d01f5.apk
hxxp://ovcloudcontrol.cdn.cardoor[.]cn/upgrade/2025-06-10/fe71af9ecf174de48d2b2ccc2c15fb04.apk
hxxp://ovcloudcontrol.cdn.cardoor[.]cn/upgrade/2024-11-07/fa831c3c23824b99871163387bcda7ad.apk

Hashes of TWCore (the legitimate software used to distribute JarService)

2a64c3efc11bf224aa54f24e876446c9
7a4d3ba2dacccfdda55859a5dfee2671
ea24487996eb70c1780922fb3063bcc5

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Since early May 2026, Microsoft Threat Intelligence has observed Storm-2945, a sub-cluster of Midnight Blizzard, conducting widespread but targeted traffic manipulation attacks involving hospitality sector networks served by captive portals worldwide. Despite some tactic, technique, and procedure (TTP) similarities to the Forest Blizzard DNS hijacking operation that we publicly disclosed in April 2026, we attribute this campaign, which we call CaptiveCrunch, to Storm-2945. As reported by ReliaQuest on July 23, a portion of this activity leverages doppelganger domains mimicking Microsoft online services to conduct follow-on adversary-in-the-middle (AitM) phishing operations that abuse the device code authentication flow in Microsoft Entra ID. Microsoft Threat Intelligence has also identified active traffic manipulation attacks leading to the delivery of malware on impacted systems. Microsoft has observed Storm-2945 leveraging AI to support a significant portion of these operations.

Today, we are sharing our findings on these ongoing intrusions to raise awareness of this threat and enable customers to protect their devices, especially while traveling. We provide our assessment of Storm-2945’s relationship to Midnight Blizzard and analysis of the CaptiveCrunch campaign, detailing the malware and tradecraft used in these operations. We also provide mitigation, detection, and hunting guidance to help organizations identify and defend against Storm-2945 and related activity.

Microsoft Threat Intelligence would like to thank our partners at Anthropic and OpenAI for their collaboration and support during this investigation.

The CaptiveCrunch campaign

Since February 2026, Storm-2945 has conducted AI-augmented operations including targeted device code and OAuth code phishing campaigns leading to Entra device registration and subsequent data collection from Microsoft 365. Since early May 2026, Microsoft Threat Intelligence has observed Storm-2945 manipulating DNS and HTTP traffic from networks served by captive portals to redirect user traffic through actor-controlled infrastructure. Although our investigation into the initial compromise vector for the captive portal networks is ongoing, we have observed notable commonalities in the equipment and management systems used across multiple affected networks. These similarities suggest that the activity might not be limited to isolated compromises of individual venues and could reflect access to shared services within portions of the captive portal ecosystem.

As part of the CaptiveCrunch campaign, Storm-2945 has leveraged their AitM position to redirect users through actor-controlled phishing infrastructure and has also delivered malware purporting to be browser or operating system updates in response to automated connectivity checks issued by users’ browsers. Multiple variants have been delivered, including fully-featured Windows remote access trojans (RAT) in compiled Golang, with functionality to conduct system enumeration, collect files and keystrokes, steal credentials and session tokens, conduct audio and video surveillance, monitor for removable media, and provide the threat actor a remote shell on infected systems.  

The threat actor infrastructure leverages a variety of ClickFix techniques to elicit the user into downloading and executing the malware:

In addition to variants of malware targeting Windows systems, Microsoft Threat Intelligence is also aware of indications that the threat actor might be targeting Android devices with similar techniques as the ClickFix landings also include instructions for Android devices to download and install an APK file.

To date, Microsoft has identified widespread compromise of Wi-Fi networks at hospitality-related organizations and other networks serviced by captive portal equipment in several countries. ReliaQuest has identified this activity not only at hotels, but also conference centers and other shared venues, and assesses that the goal of this activity is to access the accounts of corporate travelers.

Storm-2945 and Midnight Blizzard

Microsoft Threat Intelligence assesses that Storm-2945 is an operational sub-cluster of Midnight Blizzard based on distinctive technical and operational overlaps. These include technical similarities to Storm-2372, a Midnight Blizzard initial access operations sub-cluster, also notable for their device code and OAuth code phishing operations tracked throughout 2025, Microsoft Graph-based email exfiltration, social engineering delivered via commercial messaging apps, and significant similarities in victimology.

Midnight Blizzard is a Russia-based threat actor attributed by the US and UK governments to the Foreign Intelligence Service of the Russian Federation, also known as the SVR. This threat actor is known to primarily target governments, diplomatic entities, non-governmental organizations (NGOs), and information technology (IT) service providers, primarily in the US and Europe. Midnight Blizzard is consistent and persistent in their operational targeting, and their objectives rarely change. Their focus is to collect intelligence through longstanding and dedicated espionage in support of Russian foreign policy interests.

Midnight Blizzard operations often involve compromise of valid accounts and, in some highly targeted cases, advanced techniques to compromise authentication mechanisms within an organization to expand access and evade detection. They utilize diverse initial access methods, and Midnight Blizzard is also adept at identifying and abusing OAuth applications to move laterally across cloud environments and for post-compromise activity, such as email collection.

CaptiveCrunch tradecraft and tooling

CornFlake: Remote access and infostealer implant

CornFlake is a full-featured Windows RAT written in Go that serves as Storm-2945’s primary persistent implant. Microsoft has observed the threat actor rapidly iterating on this malware layer, which features customizable capabilities from the social engineering user interface and data collection capabilities to anti-detection and evasion techniques.

On initial execution, CornFlake operates in dropper mode: it displays a convincing fake progress window designed to occupy the victim’s attention while the binary copies itself to %APPDATA%\svchost32\svchost32.exe and establishes persistence.

Fake window options configurable by the threat actor at build time:

• winupdate — A Windows Update screen displaying “Working on updates… Don’t turn off your computer”
• defender — A Windows Security virus scan
• directx — A DirectX End-User Runtime Web Installer
• vcredist — A Microsoft Visual C++ 2015-2022 Redistributable installer
• sysopt — A disk optimization utility
• netfix — A Windows Network Diagnostics tool
• browser — A browser update prompt
• pdfview — A document viewer installer

CornFlake registers as a Windows service named svchost32 with the display name “Cloud Sync Service” and description “Synchronizes files with the cloud storage provider”, deliberately mimicking the legitimate svchost.exe process. It establishes redundant persistence mechanisms: Windows service registrations, Registry Run keys, named scheduled tasks, and a persistence watchdog routine that runs continuously to restore any persistence mechanism that is removed by defenders or endpoint protection.

For command and control (C2), CornFlake performs an Elliptic Curve Diffie-Hellman (ECDH) P-256 ephemeral key exchange with the C2 server, derives a session key via SHA-256, and communicates over a custom JSON protocol framed within the encrypted channel. This provides an encrypted channel to the C2 server, with each C2 session using a unique ephemeral key, making decryption of captured traffic impossible without the session-specific private key. The runtime configuration file sync.dat supports hot reconfiguration of C2 servers, watched directories, file targeting patterns, and Transport Layer Security (TLS) settings without requiring redeployment.

Once established on a victim system, CornFlake provides the operator with a comprehensive collection toolkit, gated by configuration flags that allow selective activation post-deployment:

CornFlake also exposes a localhost HTTP API server (/upload, /reload, /status) that transforms the RAT into a modular platform: companion or next-stage payloads such as ChocoShell could task file exfiltration, trigger configuration hot reloads or check C2 connectivity using the pre-established secure C2 channel for communication.

ChocoShell: PowerShell infostealer

ChocoShell is the campaign’s Powershell-based infostealer, delivered and executed entirely in-memory. Its primary objective is the high-volume theft of browser session cookies, saved passwords, Microsoft 365 Single Sign-On (SSO) tokens, and Wi-Fi credentials from compromised systems. Where CornFlake provides the operator with a persistent, long-running foothold on the device, ChocoShell is designed to extract the most operationally valuable credentials, giving the operator access to victim cloud environments.

The ChocoShell script was authored with full developer comments that reveal the operator’s intent behind each code decision, including explicit references to Microsoft detection signatures and the reasoning behind specific evasion choices. The consistent coding standard and descriptive commentary suggest the author might have leveraged AI-assisted code generation.

Defense evasion. Upon execution, ChocoShell beacons to a hardcoded C2 server at 213.145.86[.]112 and implements several evasion techniques in sequence. It disables the Antimalware Scan Interface (AMSI) via .NET reflection to prevent ScriptBlock scanning and evades Microsoft behavioral detection that triggers on suspicious PowerShell web request cmdlets. A timing-based sandbox detection check is also employed as a virtual machine (VM) detection mechanism, silently exiting without performing any collection if detected.

C2 communication. ChocoShell communicates with its C2 server using HTTPS with URI paths designed to blend in with legitimate web traffic. Beacons use /t/pixel.gif?m=<status>, mimicking an image tracking pixel. Additional tooling is fetched from /cdn/chunks/polyfill-7e2b.min.js, disguised as a JavaScript polyfill file. This downloaded module is Base64-decoded and executed in memory via [ScriptBlock]::Create(), providing browser encryption key extraction capabilities, SYSTEM token impersonation, and Defender signature locking. Exfiltrated data is sent by POST to /t/event as GZip-compressed, Base64-wrapped JSON.

Privilege escalation. ChocoShell requires administrative privileges for its most impactful capabilities: SYSTEM token impersonation for Chrome ABE decryption, Volume Shadow Copy Service (VSS) shadow copy creation, Defender signature locking. It implements three silent UAC bypass techniques with ordered fallback:

1. SilentCleanup task hijack: Writes a malicious command to HKCU\Environment\windir, then triggers the built-in SilentCleanup scheduled task, which resolves %windir% from the user’s environment, executing the threat actor’s command at elevated privilege. The registry value is cleaned up after two seconds to avoid cloud detection.
2. wsreset.exe COM hijack: Creates a COM handler key in HKCU\Software\Classes and launches the auto-elevating Windows Store reset tool.
3. sdclt.exe folder hijack: Hijacks HKCU\Software\Classes\Folder\shell\open\command and launches the Windows Backup utility with the /KickOffElev flag.

If none of the silent bypasses succeed (for example, the user is not a local administrator), ChocoShell falls back to a visible UAC prompt via Start-Process -Verb RunAs. Notably, the script also contains a variant designed to execute within the WinGet Desired State Configuration (DSC) host process (ConfigurationRemotingServer), suggesting an attack vector through malicious WinGet DSC configuration used in Windows machine provisioning.

Credential and session theft. Once running with elevated permissions, ChocoShell locks Defender signature updates and systematically harvests data from multiple sources. For Chromium-based browsers (Chrome, Edge, Brave, Opera, Opera GX, Vivaldi), it extracts the master encryption key from the browser’s Local State file, handling both the modern ABE scheme (Chrome v127+) and the legacy data protection API (DPAPI)-only scheme. ABE decryption requires SYSTEM-level DPAPI access, which the malware obtains by impersonating a SYSTEM process token borrowed from winlogon.exe, wininit.exe, or services.exe. Locked browser SQLite databases are accessed through three strategies: shared file access, Volume Shadow Service snapshots, and direct copy as a fallback.

As a parallel collection path, ChocoShell launches Chrome, Edge, and Brave with the –remote-debugging-port flag and issues Network.getAllCookies through the Chrome DevTools Protocol (CDP). This completely bypasses ABE, enabling the browser to perform its own internal decryption and returns plaintext cookie values. To handle privilege issues (SYSTEM-launched browsers inherit the wrong token), the malware creates transient scheduled tasks with TASK_LOGON_INTERACTIVE_TOKEN to launch the browser under the signed-in user’s session. After extraction, the browser is stopped and relaunched with –restore-last-session to avoid alerting the user.

For Firefox family browsers (Firefox, Waterfox, LibreWolf, Floorp, Zen), the malware copies unencrypted cookies.sqlite databases from each profile. Additionally, ChocoShell collects Microsoft 365 and Azure Active Directory (AD) access tokens, refresh tokens, and Web Account Manager (WAM) tokens from .tbres files in the Token Broker cache. Collection of these tokens represents a significant threat to enterprise environments, as threat actors could replay SSO sessions without browser cookies. Additionally, Wi-Fi credentials are harvested via netsh wlan show profile with key=clear.

Exfiltration and cleanup. All collected data is aggregated into a JSON structure, GZip-compressed, Base64-encoded, and sent by POST to the C2’s /t/event endpoint. After exfiltration, all collected data variables are nulled, garbage collection is forced, VSS shadow copies are deleted via Windows Management Instrumentation (WMI), temporary elevation scripts are removed, and all UAC bypass registry keys (already cleaned during escalation) are verified removed.

FruitStone: Operator C2 panel

FruitStone is the web-based C2 panel that Storm-2945 operators use to manage the entire CaptiveCrunch campaign infrastructure. Implemented as a single-page application (HTML and JavaScript) serving as the front-end of the C2 server with all functionality exposed without authentication, FruitStone provides a centralized dashboard for managing compromised endpoints, building and deploying new campaign payloads, and reviewing all collected data (such as screenshots, keystrokes, browser credentials).

Operational cover. The panel is branded as “CloudSync Console” with a footer reading “Acuity Systems, Inc. — Cloud Infrastructure Portal v3.2.1,” designed to appear as legitimate enterprise cloud management software if the panel URL is discovered by defenders or hosting providers. This masquerading extends to the CornFlake agent’s service name (Cloud Sync Service) and description (“Synchronizes files with the cloud storage provider”), creating a consistent cover story across the toolchain.

Session management and multi-operator support. FruitStone uses JSON Web Token (JWT)-based authentication, session revocation, and rate limiting with IP blocking to prevent brute force attacks against the panel sign in. Multiple operators could be provisioned with individual accounts, and all active sessions are visible with IP address, user-agent, and creation time to enable operational security awareness across the operators.

Agent management. The panel displays all registered CornFlake agents in a dashboard with real-time status updates via Server-Sent Events (SSE). Each agent card shows comprehensive system information including hostname, username, OS version, CPU, RAM, disk usage, screen resolution, timezone, domain membership, and camera/microphone presence, all collected during the CornFlake posture sweep. Agents are grouped by country and subnet, with geographic distribution visualized on a map.

Operators could interact with individual agents through:

• Remote shell — Interactive cmd.exe or PowerShell command execution with command history
• File system browser — Live directory traversal and arbitrary file download from compromised hosts
• Collection tasking — On-demand screenshot, process list, keylog buffer flush, clipboard dump, security posture survey, ChromeKatz cookie/password extraction, camera capture, and audio recording
• Configuration push — Live runtime reconfiguration of C2 servers, watch paths, and C2 beacon timing
• Agent update — In-place implant update by pushing a new CornFlake build to a running agent
• Agent kill — Remote termination of the CornFlake implant

Campaign builder. A step-by-step wizard enables operators to configure and build new CornFlake payloads directly from the panel:

1. Identity — Campaign ID, C2 host and port, HTTP base URL, executable file name (svchost32.exe by default), and dropper type (C dropper at ~19 KB, Go stub at ~8 MB, or standalone self-installer)

2. Capabilities — Toggle individual collection modules: screenshots, process enumeration, keylogging, clipboard monitoring, posture survey, file exfiltration, and ChromeKatz browser credential theft

3. File Paths — Configure targeted directories and file extensions by category (documents, archives, images, code, data, emails, encryption keys)

4. Evasion — Enable garble symbol randomization (for GoLang payloads), XOR string encoding, GZip upload compression, and debug mode

Infrastructure management. FruitStone provides management interfaces for three layers of supporting infrastructure:

• Proxy relays — Multi-proxy C2 relay architecture with TLS certificate tracking (fingerprint, expiry), health checks, connection counts, bytes forwarded, and rotation capabilities that push updated server lists to all online agents
• Beacon profiles — Configurable timing profiles controlling agent sleep intervals, reconnection delays, TLS Server Name Indication (SNI) spoofing (like teams.microsoft.com), and DNS fallback domains
• Staging servers — External payload hosting infrastructure with push-to-deploy, file listing, and health monitoring

Device code abuse for cloud access

Since July 16, Microsoft has observed a portion of CaptiveCrunch landing pages redirecting users to device code authentication flow experiences. In these cases, users served these landings might be instructed to enter a device code into a legitimate Microsoft sign-in page, a technique commonly referred to as device code phishing.

Device code authentication is a legitimate OAuth workflow designed for devices that cannot support a traditional sign-in experience. However, threat actors could abuse this flow by initiating an authentication request on behalf of a user then convincing the user to enter an actor-controlled device code into a legitimate Microsoft authentication page. When successful, the victim authenticates the threat actor’s session rather than their own.

This activity is consistent with previously reported device code phishing operations conducted by Midnight Blizzard since August 2024. The observed technique does not appear fundamentally novel; however, integrating device code phishing into captive portal and traffic manipulation operations might increase the likelihood that users perceive the authentication request as legitimate. For additional details on Midnight Blizzard-related device code phishing techniques, see: Storm-2372 conducts device code phishing campaign. To understand other threat actors’ use of device code phishing and associated mitigations, see Inside an AI‑enabled device code phishing campaign.

How to protect against CaptiveCrunch activity

Minimize trust in hospitality and guest networks

When traveling, users should treat hotel, conference, airport, and other guest wireless networks as untrustworthy.

• Prefer private connectivity (including mobile hotspots, satellite, and eSIM-based cellular data connections) over public Wi‑Fi whenever practical.
  • For enterprise-managed devices, organizations can choose to prevent Wi-Fi connections to networks that have not been provisioned via Mobile Device Management (MDM). See: https://learn.microsoft.com/windows/client-management/mdm/policy-csp-wifi#allowmanualwificonfiguration
• Consider using enterprise-managed travel routers or hotspot devices that establish encrypted tunnels back to trusted corporate infrastructure before accessing sensitive resources.
• Avoid downloading software updates, certificates, browser updates, network troubleshooting tools, or security utilities presented through captive portals or other unexpected web prompts.
• Verify update requests through trusted operating system mechanisms rather than pop-up messages or website prompts.

Strengthen identity and access controls

Organizations should assume that public and hospitality network infrastructure might not be trustworthy and should adopt controls that limit exposure to traffic manipulation, credential theft, and device code phishing.

• Educate users to recognize ClickFix-style prompts, fake verification checks, and paste-and-run instructions as malicious, especially when they invoke command interpreters or script hosts such as cmd.exe, PowerShell, rundll32.exe, or mshta.exe.
• Use passwordless solutions like passkeys and implement multifactor authentication (MFA).
  • Use the Microsoft Authenticator app for passkeys and MFA, and complement MFA with conditional access policies, where sign-in requests are evaluated using additional identity-driven signals.
  • Conditional access policies can also be scoped to strengthen privileged accounts with phishing resistant MFA.
  • Your passkey and MFA policy can be further secured by only allowing MFA and passkey registrations from trusted locations and devices.
• Only allow device code flow where necessary. Microsoft recommends blocking device code flow wherever possible. Where necessary, configure Microsoft Entra ID’s device code flow in your Conditional Access policies.
• Implement a sign-in risk policy to automate response to risky sign-ins. A sign-in risk represents the probability that a given authentication request is not authorized by the identity owner. A sign-in risk-based policy can be implemented by adding a sign-in risk condition to Conditional Access policies that evaluates the risk level of a specific user or group. Based on the risk level (high/medium/low), a policy can be configured to block access or force MFA.
  • When a user is a high risk and Conditional access evaluation is enabled, the user’s access is revoked, and they are forced to re-authenticate.
  • For regular activity monitoring, use Risky sign-in reports, which surface attempted and successful user access activities where the legitimate owner might not have performed the sign-in. 
• Use a Security Service Edge (SSE) solution like Global Secure Access to secure access to any app or resource using network, identity, and endpoint access controls.

Reduce exposure during captive portal registration

Organizations should review what information employees provide to hospitality providers when connecting to guest networks.

• Do not reuse corporate credentials on hotel, conference, or guest-network registration pages.
• Where possible, organizations should evaluate whether venue-provided wireless is required for corporate events and conferences.
• Organizations should minimize unnecessary disclosure of employee identities, organizational affiliations, and travel details when booking accommodations or registering for guest network access, consistent with corporate policy and applicable local requirements.

Microsoft Defender detections and hunting guidance

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender for Endpoint detects Storm-2945 activity under the detection Suspicious activity linked to a Russian state-sponsored threat actor has been detected. However, these alerts might be triggered by unrelated threat actor activity. The following chart lists Microsoft Defender detections specific to the TTPs utilized by Storm-2945 in this attack.

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

• Actor profile: Midnight Blizzard

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Detect file creation after Wi-Fi connectivity test on devices

The following query checks for a file creation on a device within two minutes of the device performing built‑in Network Connectivity Status Indicator (NCSI) test, which occurs when network connectivity is established to a Wi-Fi network with a captive portal. This activity might indicate an attacker’s initial access file presence on a device.

Please note that not all files discovered through this query might be malicious or related to this threat activity.

let ncsi_endpoints = dynamic(["msftconnecttest.com","edge-http.microsoft.com","msftncsi.com","captive.apple.com","clients1.google.com",
    "clients3.google.com","clients4.google.com","clients6.google.com","connectivitycheck.gstatic.com","connectivitycheck.android.com",
    "android.clients.google.com","www.gstatic.com","detectportal.firefox.com","detectportal.brave-http-only.com","cloudflareportal.com",
    "cloudflarecp.com","cloudflareok.com","connectivity-check.warp-svc","connectivity.cloudflareclient.com","spectrum.s3.amazonaws.com",
    "nmcheck.gnome.org"]);
let NCSIEvents = DeviceNetworkEvents
    | where Timestamp > ago(7d)
    | where RemoteUrl has_any (ncsi_endpoints)
    | project NCSI_Timestamp = Timestamp, DeviceId, DeviceName, RemoteUrl, NCSI_ReportId = ReportId, NCSI_InitiatingProcessFileName = InitiatingProcessFileName, NCSI_InitiatingProcessCommandLine = InitiatingProcessCommandLine, NCSI_AccountName = InitiatingProcessAccountName;
let FileDownloadEvents = DeviceFileEvents
    | where Timestamp > ago(7d)
    | where ActionType == "FileCreated"
    | where FileName has_any (".exe",".msi",".zip",".rar",".7z")
    | project Download_Timestamp = Timestamp, DeviceId, FileName, FolderPath, Download_ReportId = ReportId, Download_InitiatingProcessFileName = InitiatingProcessFileName, Download_InitiatingProcessCommandLine = InitiatingProcessCommandLine, Download_AccountName = InitiatingProcessAccountName;
NCSIEvents
| join kind=inner (
    FileDownloadEvents
) on DeviceId
| where Download_Timestamp >= NCSI_Timestamp and Download_Timestamp 

Detect connectivity to Storm-2945 infrastructure

The following query checks for connectivity to Storm-2945 infrastructure observed in this attack activity.

let target_domains = dynamic(["ms365-device.com", "ms365-live.com", "m365-owa.com", "owa-ms365.com"]);
let target_ips = dynamic(["31.57.243.154", "38.146.28.75", "38.146.28.132", "104.194.159.150", "107.189.26.194", "213.145.86.112"]);
DeviceNetworkEvents
| where RemoteUrl has_any(target_domains) or RemoteIP in (target_ips)
| project
    Timestamp,
    DeviceName,
    DeviceId,
    RemoteUrl,
    RemoteIP,
    LocalIP,
    InitiatingProcessFileName,
    InitiatingProcessCommandLine,
    AccountName = InitiatingProcessAccountName,
    ReportId

Detect CornFlake RAT presence on affected systems

The following query checks for the presence of the CornFlake RAT binary.

DeviceProcessEvents
| where FolderPath == "%APPDATA%\\svchost32\\svchost32.exe"
   or FolderPath endswith @"\svchost32\svchost32.exe"
| project Timestamp, DeviceName, DeviceId, FileName, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine, AccountName, ReportId

Detect CornFlake RAT Windows service registration

The following query checks for the CornFlake RAT Windows service registration.

DeviceRegistryEvents
| where RegistryKey has @"\SYSTEM\CurrentControlSet\Services\svchost32"
| where ActionType == "RegistryValueSet"
| where (RegistryValueName == "DisplayName" and RegistryValueData == "Cloud Sync Service")
    or (RegistryValueName == "Description" and RegistryValueData == "Synchronizes files with the cloud storage provider")
| project
    Timestamp,
    DeviceName,
    DeviceId,
    RegistryKey,
    RegistryValueName,
    RegistryValueData,
    ActionType,
    InitiatingProcessFileName,
    InitiatingProcessCommandLine,
    InitiatingProcessAccountName,
    ReportId

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map’) to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the Threat Intelligence solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace.

Detect network IP and domain indicators of compromise using ASIM

The following query checks IP addresses and domain IOCs across data sources supported by ASIM network session parser:

//IP list and domain list- _Im_NetworkSession
let lookback = 30d;
let ioc_ip_addr = dynamic(["213.145.86.112"]);
let ioc_domains = dynamic(["213.145.86.112/t/pixel.gif", "213.145.86.112/cdn/chunks/polyfill-7e2b.min.js", "213.145.86.112/t/event"]);
_Im_NetworkSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or DstDomain has_any (ioc_domains)
| summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, DstDomain, Dvc, EventProduct, EventVendor

Detect web sessions IP and file hash indicators of compromise using ASIM

The following query checks IP addresses, domains, and file hash IOCs across data sources supported by ASIM web session parser:

//IP list - _Im_WebSession
let lookback = 30d;
let ioc_ip_addr = dynamic(["213.145.86.112"]);
let ioc_sha_hashes =dynamic([“918fa52ae45ed60ba7cc8bdc99c3cbe9ab92e0375ec31fc05d0d4513be11c593”, “be99857449d2856dd5a84e21c8a3d5e0e01456adb44062ddec5a6b4970d8d42c”]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or FileSHA256 in (ioc_sha_hashes)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Detect domain and URL indicators of compromise using ASIM

The following query checks domain and URL IOCs across data sources supported by ASIM web session parser:

// file hash list - imFileEvent
// Domain list - _Im_WebSession
let ioc_domains = dynamic(["https://213.145.86.112/t/pixel.gif", "https://213.145.86.112/cdn/chunks/polyfill-7e2b.min.js", "https://213.145.86.112/t/event"]);
_Im_WebSession (url_has_any = ioc_domains)

ChocoShell C2 communications

The following query detects ChocoShell communications with its C2 server using HTTPS with URI paths designed to blend in with legitimate web traffic. Beacons use /t/pixel.gif?m=<status>, mimicking an image tracking pixel.

let lookback = 30d;
let ioc_url_artifacts = dynamic(["/t/pixel.gif?m="]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstDomain  in (ioc_url_artifacts)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Indicators of compromise

References

• https://reliaquest.com/blog/threat-spotlight-dns-poisoning-tactics-expand-to-hospitality/
• https://www.volexity.com/blog/2025/02/13/multiple-russian-threat-actors-targeting-microsoft-device-code-authentication

Learn more

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The post CaptiveCrunch: Midnight Blizzard targets travelers worldwide for malware delivery and credential theft appeared first on Microsoft Security Blog.

Introduction

The new GenieLocker ransomware family has been active since March 2026. It has been used in attacks against organizations in the Russian Federation, primarily in the manufacturing sector, and attributed to the Toy Ghouls group by open-source intelligence (link in Russian).

The Toy Ghouls, also known as Bearlyfy, Labubu and Laboo.boo, is a financially motivated extortion group, which previously relied on third-party encryption Trojans like RedAlert, LockBit, and Babuk. GenieLocker, apparently a custom design, upgrades their toolkit and reduces their reliance on third-party software. We discovered multiple samples of this Trojan in two variants: PE builds for Windows and ELF builds for Linux and ESXi.

Technical details

Modus operandi

We described typical TTPs and modus operandi of the Toy Ghouls threat actor in the previous post (link in Russian).

In this article, we aim to thoroughly describe the capabilities of Windows and Linux builds of the custom encryption Trojan GenieLocker. To give more context, we will also provide a brief overview of the attack that took place at the end of March 2026, where GenieLocker was deployed on the victim’s systems.

Initial Access

During the incident, the attackers first entered the environment through an OpenVPN connection originating from an external partner’s network. They likely exploited the trusted relationship with that partner and used stolen, yet still valid, credentials to connect.

Discovery and Credential Access

After breaching the target’s network, the attackers installed additional tools on the compromised hosts, including OpenSSH, socks5.exe, SoftPerfect Network Scanner, and Mimikatz. They employed SoftPerfect Network Scanner for discovery and used Mimikatz to dump credentials. Forensic analysis also shows that they accessed the KeePassXC password manager already installed on several compromised machines, likely attempting to extract the stored credentials from the KeePass databases.

Lateral Movement and Command and Control

Lateral movement was performed by using RDP to reach Windows machines and SSH for Linux servers. The widespread deployment of the encryption Trojan was conducted with the legitimate utilities PsExec and PAExec. Additionally, the attackers established a reverse SSH tunnel to communicate with their command‑and‑control server.

Impact

During the impact phase, the attackers encrypted files on the compromised Windows machines with the PE version of the GenieLocker ransomware. On the compromised Linux and ESXi servers, they stopped active virtual machines and encrypted their disks using the ELF version of GenieLocker.

The tactics, techniques, and procedures seen here match those documented in earlier attacks attributed to the Toy Ghouls group. As in those prior incidents, forensic analysis found no evidence of data exfiltration, which is typical behavior for this threat actor. Toy Ghouls have not employed a double‑extortion model and do not run a data‑leak website.

Encryption Trojan for Windows

The Windows version of GenieLocker (MD5: 5d62c1349b8981c396c9a23f4f8f053c) is primarily written in C, but compiled with the C++ libraries using Microsoft Visual C/C++. The malware incorporates several ransom‑related capabilities, including process termination, service shutdown, debugger evasion, and a sophisticated encryption routine. For its cryptographic operations, it relies on the open‑source libsodium library.

Aligned with the recent trend supported by our expertise, as observed in attacks of some other ransomware strains, GenieLocker doesn’t save the ransom notes on the victim’s system. The Trojan doesn’t contain any attackers’ contact info or negotiation addresses. Instead, the attackers will need to deliver the ransom demands and contacts manually during the attack. This approach may be an attempt by the GenieLocker developers to avoid proactive detection of the ransomware process being triggered by the creation of multiple readme files.

GenieLocker help message

Arguments and launch

GenieLocker supports multiple arguments for configuring its behavior.

GenieLocker expects the first argument to be a hex string referred to in the malware code as the “secret argument”, which is required for the ransomware to start. Most likely, the purpose of this is to avoid execution on sandboxes and other automated analysis environments. Another reason may be to prevent unauthorized usage by other threat actors.

Checking the secret argument

The secret argument is a hex value with a variable size that does not exceed 4096 bytes. This hex string value is converted to bytes and hashed with the SHA‑256 algorithm. The result is compared to a hardcoded value. If they match, the literal string session is appended to the secret value, and the whole string is hashed with BLAKE2b‑256, but the resulting hash is never used. This may be a part of a feature still in development.

Secret value hashing

Anti-debugging

GenieLocker contains multiple methods to inspect if its process is under debugging. After launch it makes the first check named Environment check and uses WinAPI functions IsDebuggerPresent and CheckRemoteDebuggerPresent to detect the debugger.

Environment check

After the secret argument validation, GenieLocker starts a new parallel thread called watchdog. It runs in an infinite loop that performs a number of checks to detect well-known debuggers every 500 milliseconds. If at least one of the checks fails, the whole GenieLocker process immediately terminates.

Watchdog checks

The only thing worth elaborating on is that the GenieLocker process calculates the CRC32 of its .text section when the watchdog thread is starting, saves the resulting hash, and then recalculates it again in every loop and compares with the initial value. In case the code in this section is modified by the debugger or other program, this method allows the Trojan to detect this modification.

Preparing for encryption

GenieLocker contains multiple exclusion lists. For example, it does not encrypt folders with names from the list below. Among those, there are mostly system folders, which are skipped to avoid corrupting the OS.

$recycle.bin;config.msi;$windows.~bt;$windows.~ws;windows;boot;program files;program files (x86);programdata;system volume information;tor browser;windows.old;intel;msocache;perflogs;x64dbg;public;all users;default;microsoft;appdata

The Trojan also avoids encrypting the following system Windows files.

autorun.inf;boot.ini;bootfont.bin;bootsect.bak;desktop.ini;iconcache.db;ntldr;ntuser.dat;ntuser.dat.log;ntuser.ini;thumbs.db;GDIPFONTCACHEV1.DAT;d3d9caps.dat

The file extensions below are excluded from encryption as well.

386;adv;ani;bat;bin;cab;cmd;com;cpl;cur;deskthemepack;diagcab;diagcfg;diagpkg;dll;drv;exe;hlp;icl;icns;ico;ics;idx;ldf;lnk;mod;mpa;msc;msp;msstyles;msu;nls;nomedia;ocx;prf;ps1;rom;rtp;scr;shs;spl;sys;theme;themepack;wpx;lock;key;hta;msi;pdb;search-ms;MD

Furthermore, the Trojan contains an exclusion list for host names. The malware retrieves the computer name using GetComputerNameA and checks it against this list, but in the sample in question, the list is empty.

Output for whitelisted hosts

If the host name is not excluded, GenieLocker starts to kill processes that could be using the files of interest and therefore prevent the Trojan from encrypting them. These processes are listed below. The Trojan stops them by using the TerminateProcess function.

sql;oracle;ocssd;dbsnmp;synctime;agntsvc;isqlplussvc;xfssvccon;mydesktopservice;ocautoupds;encsvc;firefox;tbirdconfig;mydesktopqos;ocomm;dbeng50;sqbcoreservice;excel;infopath;msaccess;mspub;onenote;outlook;powerpnt;steam;thebat;thunderbird;visio;winword;wordpad;notepad;calc;wuauclt;onedrive;1c;vmwp;vmms;vmcompute;mssqlserver

Additionally, the Trojan stops the following services using ControlService with the SERVICE_CONTROL_STOP control code.

vss;sql;svc$;memtas;mepocs;msexchange;sophos;veeam;backup;GxVss;GxBlr;GxFWD;GxCVD;GxCIMgr;1c;Mssqlserver;vmwp;vmms;vmcompute;mssqlserver;agent_ovpnconnect

Finally, GenieLocker starts encryption threads and searches for all available drives, including network shares, to encrypt them.

Threads info output

File encryption and cryptography

The extension for the encrypted files is hardcoded in the Trojan’s body. In the sample under review, it is .03ffc1c4a3da0f02. Before starting to encrypt each file, GenieLocker creates two auxiliary files:

• a lock file: <filename.fileext>.03ffc1c4a3da0f02.lock
• a journal: <fileext>.03ffc1c4a3da0f02.journal

The lock file helps to protect files from double encryption by other threads or instances. Inside this file, the Trojan stores the current PID obtained from the GetCurrentProcessId function.

The journal file contains the hardcoded string VCJOURN, value 1 (possibly version), some unused zeroed fields, total blocks to encrypt, and the count of blocks that are actually encrypted. The last field is a CRC32 hash sum for the integrity check of the journal content.

Journal content

By default GenieLocker encrypts files using 0x1000000-byte chunks. If the argument -p is passed (it sets the percentage of the file contents to be encrypted), the ransomware calculates how many chunks with 0x1000000 size are necessary to encrypt the specified percentage. Each chunk has a random position inside the file. Regardless of whether the percentage is set, even if it is zero, the first chunk in the beginning of the file will be encrypted anyway.

The Trojan encrypts the file content using the Authenticated Encryption with Associated Data (AEAD) algorithm XChaCha20-Poly1305, with a unique key and nonce for each file. The Trojan also adds a footer that contains the data necessary for future decryption and metadata. The metadata parts are encrypted using the same cipher and key as the file contents, but with a different nonce. The file key is encrypted using the Curve25519-XSalsa20-Poly1305 scheme, with the attackers’ master public key hardcoded in the Trojan’s body.

The metadata of each encrypted file contains the following fields.

The chunks bitmask contains as many bits as the maximum number of chunks inside a file at 100%. If a bit at a specific index is set to 1, the chunk is encrypted. The value 0 means that the chunk is not encrypted. Since the Trojan encrypts files based on the percentage value, it needs to know which chunks were encrypted.

Metadata structure at the end of an encrypted file (without a Poly1305 tags array or bitmask)

Encryption Trojan for ESXi and Linux

Compared with its Windows counterpart, the Linux and ESXi version of GenieLocker (MD5: 9201e35e2993612612919a3c71302cab) is simpler: there is no secret argument, anti‑debugging techniques, or exclusion lists. However, the sample has ESXi-specific features, such as double‑fork support and the ability to modify the Welcome Message. The sample has the version v1 and, similarly to the Windows version, uses the libsodium library for cryptography.

ESXi version description

The command‑line help output mirrors LockBit’s styling, reinforcing the theory that GenieLocker’s creators set out to craft a LockBit‑style replacement for their own operations.

LockBit output design, possibly the source layout for the GenieLocker ESXi variant

Based on the default path of the encryption directory /vmfs/volumes, we can assume that this version is intended primarily for ESXi. Nonetheless, it can still be executed on Linux distributions.

ESXi and Linux features

This build allows daemonizing its process with the -d flag, employing the classic double‑fork method so the new process becomes fully detached from its parent.

This variant also modifies the /etc/vmware/welcome file, which contains the Welcome Message (Message of the Day) on the ESXi operating system. On Linux distributions, it does not change anything, because they use different paths for the Message of the Day. In the GenieLocker sample examined here, the message is left empty.

Additionally, the ESXi version supports a few basic features that are not included in the Windows version. For instance, there is a launch‑delay option and the ability to set the number of encryption worker threads. This build also includes several features that already exist in the Windows variant, such as configuring the percentage of a file to encrypt, choosing the target directory, and setting the log file location.

File encryption

The encryption scheme for files is identical to the Windows version. The Trojan uses XChaCha20-Poly1305 to encrypt the file content and metadata, and Curve25519-XSalsa20-Poly1305 for key encryption.

File encryption summary

Victims

According to KSN telemetry, GenieLocker detections are overwhelmingly concentrated on endpoints located in the Russian Federation. In the March 2026 campaign, the primary sector under siege was manufacturing, with construction trailing closely, followed by financial services, retail, and technology.

Conclusions

Toy Ghouls are ramping up their campaign against Russian enterprises. The rollout of their home‑grown encryption Trojan GenieLocker marks a major upgrade to the group’s ransomware toolkit. By engineering bespoke ransomware that runs natively on Windows, Linux, and ESXi, the actor has cut their dependence on off‑the‑shelf ransomware families and unified the cryptographic backbone across all targeted platforms.

Kaspersky’s products detect this malware as Trojan-Ransom.Win64.Agent.genie, HEUR:TrojanRansom.Win64.Generic, Trojan-Ransom.Linux.Agent.genie.

Indicators of compromise

Additional information about this threat is available to customers of the Kaspersky Threat Intelligence Reporting service. Contact: intelreports@kaspersky.com.

GenieLocker for Windows

A50EAAF514F4F84E61CA2455A8789753 kftd.exe, genie_encrypt.exe
F08F476F26B01D142CA73923DE65FC0C
FD46A80C2F45577263328984EDF7F4DC
DE3CFBB50F66079BFEE20A6F64E59433
780C8F4C6F077DA4DA96582987920362
D87D0B01D95ACC936B7DC47B8F41937A run.exe, genie_encrypt.exe
34A7F28E0BB69B0D49BACC88BDF20AC1 run.exe, run2.exe, genie.exe
5D62C1349B8981C396C9A23F4F8F053C genie_encrypt.exe
A8842616C9057D5CF6E1FE1FA8C3C160
34B8828635F88078735799A3C1AC8E28
D3E06EB34D8EEE7EF92CAC3AD0A20FF5
C68B6862725777651085650DB34947FC consultant.exe
9CD514FF2809CE0B993E3B8649E82A94
824CA1E906CC073EE5B0F3519DF69A8F
25480DAD40152EF3D0C6D38EECC9BD9B
7DAD78584795AA5C160520CC6ACCF260
18F61C6D686CFFD131C9FD3F3437064B tempo.exe, kernel.exe
9969A8221312DBA70DD5CBDDF83A146C
F7B9E36E94163A9A303160945F99267A
B893EAFED0659F70D4AC250F09073723
D661CF666B9ACBAB7CFEAE1127A261A9 genie.exe
3A4479B51890373BFC4A011EF41FE376
58C0DDA52B8F069660166D61FD74F911

GenieLocker for Linux and ESXi

9201E35E2993612612919A3C71302CAB vzdump

C2

89[.]125.66.101

If you use and install packages from npm or PyPI, the first hours after a package is published are the riskiest because scanners can’t analyze packages before publication. Recent supply chain events affecting NodeJS and Python packages have been detected and removed within hours. However, while those packages were available to the general public, it’s possible that they were installed by users, creating the potential for a security incident. As you will see from the data that follows, if users had waited 1 day before accessing those packages, none of the recent supply chain security events would have had an impact.

In this post, I show you a one-line configuration that you can use to eliminate this exposure in your environment: a dependency cooldown for npm and pip. This change tells your package manager to skip versions published in the last 24 hours, giving the security community time to detect and remove unexpected packages before they reach your systems. These settings secure the default setup. There’s another use case of package updates: receiving security fixes to address security risks. This process involves updating packages to a more recent version. I also show you how to override the cooldown configuration so you can install the latest security patches while newly installed package updates are delayed. We recommend that you assess the severity of code defects and apply security fixes if there’s known risk. Handling security fixes based on their severity—and how to specify SLAs for these fixes based on severity—is beyond the scope of this blog post.

Software delivered by Amazon Linux packages go through review by Amazon package maintainers and pass guardrails before release. Open source software is developed and maintained with similar processes and guardrails. The npm and PyPI registries have open publishing access and don’t enforce reviews. Unexpected packages are potentially added to the registries because of risks like impersonation or stolen credentials. You’re caught between two risks: older software accumulates unpatched vulnerabilities, while new packages potentially contain unexpected vulnerabilities that haven’t been detected yet. The best approach is to stay current without adopting the newest releases immediately, while applying recommended security fixes. The following diagram illustrates the relation between the two types of risks in an abstract way, where the supply chain risk is highest immediately after a package is published, because unexpected updates can potentially bypass guardrails. After a package is published, auditing can review it and identify potential defects over time. If no security fixes are applied, the risk of all the code defects adds up.

Figure 1: Software risk over lifetime. Unpatched vulnerabilities risk increases over time. Very recent software also carries more supply chain risk.

Supply chain events follow a consistent pattern. An unexpected author publishes an unexpected package or package version and waits for automated systems and users to pull it in. Security researchers and automated scanners typically detect and remove these packages within hours, but by then, systems have been exposed to the risk.

Datadog’s 2026 State of DevSecOps report found that 54% of JavaScript applications install at least one dependency within a day of its release. That’s the time window that presents the highest supply chain risk. Recent events show how fast detection happens:

A dependency cooldown tells your package manager to skip recently published versions. If a version hasn’t existed on the registry for the configured timespan, for example, 1 day, it won’t be installed, giving the security community time to detect and remove unexpected versions.

A 1-day cooldown blocks each event listed in the preceding table. Notably, several of these events produced valid provenance attestations and passed build verification. These provenance checks alone didn’t stop them. A cooldown works independently of authorization mechanisms, because it blocks by age rather than by trust.

Both npm (v11.10.0+) and pip (v26.1+) support cooldowns . Amazon Linux 2023 ships these packages in NodeJS 24 and Python 3.14 since release 2023.11.20260608.

If you use lockfile-based installations through npm ci or pip install -r requirements.txt with pinned versions, you won’t pull latest package updates. The cooldown doesn’t apply to those installations. The cooldown only affects resolution of new or updated packages. See the Lockfile-based installs and the cooldown section for details.

To implement the following solution, you first need to have the following prerequisites in place:

• Node.js 24 with npm 11.10.0 or later (in nodejs24-24.14.1-1.amzn2023.0.1 or later).
• Python 3.14 with pip 26.1 (in python3.14-pip-26.1.1-1.amzn2023.0.1 or later)
• pip-audit (tool to scan python packages required for defect-based override scripts). Use python3.14 -m pip install pip-audit to install.

Future versions of Node.js and Python will bring new commands. The following tool commands work for Amazon Linux 2023 with Node.js 24 and Python 3.14. The provided commands target specific package versions. Adjust the commands if you use later releases.

1. Create the global configuration directory, depending on your NodeJS version.
   sudo mkdir -p /usr/lib/nodejs24/etc
2. Add the npm configuration file with the cooldown setting.
   sudo npm-24 config set min-release-age 1 --location=global
3. Check that the cooldown is active by running the next command.
   npm-24 config list

You will see before = "<timestamp from 24 hours ago>" in the output, confirming npm converted the 1-day cooldown into a date filter.
For more information, see the npm min-release-age documentation.

1. Create the system-wide pip configuration file with the cooldown setting.
   sudo python3.14 -m pip config set --global global.uploaded-prior-to P1D
2. Verify the configuration (for Python 3.14 and pip 26.1+).
   python3.14 -m pip config list

You will see global.uploaded-prior-to='P1D' in the output.

This configuration is safe to deploy immediately, because older pip versions (25.x) silently ignore the setting.

What if you want to install the latest version of a package, for example to receive security fixes? The following sections describe how to override the flag using the tool command line. To identify which packages need urgent updates, run the appropriate audit command for your package manager.

npm auditor python3.14 -m pip_audit

Install the package with the cooldown override.
npm-24 install <package-name> --min-release-age=0

Install the package with the cooldown override.
python3.14 -m pip install <package-name> --uploaded-prior-to="P0D"

We recommend that you apply security fixes for packages that have known security risks. You don’t need to turn off the cooldown entirely to apply security fixes. Use the audit tools to identify packages with known issues, then override the cooldown for only these packages.

Prerequisites: Ensure you have Python 3 and pip-audit installed (python3.14 -m pip install pip-audit).

Important: These scripts demonstrate the concept. For production use, add error handling, logging, and testing. Review packages before updating them in automated pipelines.

The following script demonstrates the required steps to identify npm packages with a known security fix. The npm audit command prints these packages as JSON. Next, packages in this list are updated with an npm install command, where their cooldown is overridden so that the latest version is picked up.

npm audit --json | python3 -c "
import json, sys, subprocess
data = json.load(sys.stdin)
for pkg in data.get('vulnerabilities', {}):
    subprocess.run(['npm-24', 'install', f'{pkg}@latest', '--min-release-age=0'])
"

The following script demonstrates the required steps to identify pip packages with a known security fix. The pip_audit command prints these packages as JSON. Next, all packages in this list are updated with an pip install command that overrides the cooldown so that the latest version can be picked up.

python3.14 -m pip_audit --format=json | python3.14 -c "
import json, sys, subprocess
from packaging.version import Version
data = json.load(sys.stdin)
for dep in data.get('dependencies', []):
    pkg = dep['name']
    vulns = dep.get('vulns', [])
    if not vulns:
        continue
    fix_versions = [v for vuln in vulns for v in vuln.get('fix_versions', [])]
    if not fix_versions:
        print(f'{pkg}: vulnerable but no fix published, skipping')
        continue
    fix = max(fix_versions, key=Version)
    print(f'Updating {pkg} -> {fix}')
    subprocess.run(['python3.14', '-m', 'pip', 'install', f'{pkg}=={fix}', '--uploaded-prior-to=P0D'])
"

If you use npm ci or pip install -r requirements.txt with pinned versions, the cooldown doesn’t apply. These commands install what the lockfile specifies, regardless of package age. The cooldown only affects resolution of new or updated packages.

Major package managers and enterprises have started to adopt dependency cooldowns. As of May 2026, several popular package management tools now include cooldown features: pnpm (a fast Node.js package manager), Renovate (an automated dependency update tool), and StepSecurity (a supply chain security platform).

• pnpm 11 ships with minimumReleaseAge enabled by default. It’s one of the first major package manager to make cooldowns opt-out rather than opt-in.
• Renovate’s config best-practices preset has included a 3-day npm cooldown since 2025 and is widely adopted across enterprises.
• StepSecurity Secure Registry uses a configurable cooldown period for enterprise customers. StepSecurity recommends a 10 day delay as default.

AWS scans upstream package registries to catch unexpected packages before they reach customers.

• Amazon Inspector, a security management service that continuously scans workloads for software vulnerabilities and network exposure, uses AI-assisted detection rules to scan upstream package registries. In 2025, Amazon Inspector researchers identified over 150,000 unexpected npm packages linked to a token farming campaign.
• AWS Security published detailed response guidance for the Shai-Hulud worm and the axios event.
• AWS contributes to the Open Source Security Foundation $12.5M grant for open source security, funding proactive scanning infrastructure that benefits the entire ecosystem.

Unexpected packages are typically caught within hours of publication. A 1-day cooldown ensures you don’t install them during that detection window.

To secure your Amazon Linux 2023 configuration:

1. Set a 1-day cooldown for npm and pip as shown in the preceding sections. External registries don’t have human review, so give the defenders time to catch problems.
2. Override when needed for urgent security patches using the per-command flags.
3. Run npm audit or pip_audit regularly to identify packages that need immediate attention.

Set up the cooldown with one line of configuration, and the protection is immediate.

By implementing the solutions presented in the post, you secure your npm and PyPI environment from most instances of unexpected code. The update delay of 1 day protects your environment, while still allowing to apply the latest security fixes. To learn about how to protect your environment further, see the following resources:

• NodeJS Security best practices
• npm min-release-age documentation
• Pip Secure installs documentation
• pip uploaded-prior-to documentation
• OpenSSF Best Practices
• Amazon Linux 2023 documentation

If you have feedback about this post, submit comments in the Comments section below.