In identity-based attack campaigns, any initial access activity can turn an already serious intrusion into a critical incident once it allows a threat actor to obtain domain-administration rights. At that point, the attacker effectively controls the Active Directory domain: they can change group memberships and Access Control Lists (ACLs), mint Kerberos tickets, replicate directory secrets, and push policy through mechanisms like Group Policy Objects (GPOs), among others.
What makes domain compromise especially challenging is how quickly it could happen: in many real-world cases, domain-level credentials are compromised immediately following the very first access, and once these credentials are exposed, they’re often abused immediately, well before defenders can fully scope what happened. Apart from this speed gap, responding to this type of compromise could also prove difficult. For one, incident responders can’t just simply “turn off” domain controllers, service accounts, or identity infrastructure and core services without risking business continuity. In addition, because compromised credential artifacts can spread fast and be replayed to expand access, restoring the identity infrastructure back to a trusted state usually means taking steps (for example, krbtgt rotation, GPO cleanup, and ACL validation) that could take additional time and effort in an already high-pressure situation.
These challenges highlight the need for a more proactive approach in disrupting and containing credential-based attacks as they happen. Microsoft Defender’s predictive shielding capability in automatic attack disruption helps address this need. Its ability to predict where attacks will pivot next and apply just in time hardening actions to block credential abuse—including those targeting high-privilege accounts like domain admins—and lateral movement at near-real-time speed, shifting the advantageto the defenders.
Previously, we discussed how predictive shielding was able to disrupt a human-operated ransomware incident. In this blog post, we take a look at a real-world Active Directory domain compromise that illustrates the critical inflection point when a threat actor achieves domain -level control. We walk through the technical details of the incident to highlight attacker tradecraft, the operational challenges defenders face after domain compromise, and the value of proactive, exposure-based containment that predictive shielding provides.
Predictive shielding overview
Predictive shielding is a capability in Microsoft Defender’s automatic attack disruption that helps stop the spread of identity-based attacks, before an attacker fully operationalizes stolen credentials. Instead of waiting for an account to be observed doing something malicious, predictive shielding focuses on moments when credentials are likely exposed: when Defender sees high-confidence signals of credential theft activity on a device, it can proactively restrict the accounts that might have been exposed there.
Essentially, predictive shielding works as follows:
Defender detects post-breach activity strongly associated with credential exposure on a device.
It evaluates which high-privilege identities were likely exposed in that context.
It applies containment to those identities to reduce the attacker’s ability to pivot, limiting lateral movement paths and high-impact identity operations while the incident is being investigated and remediated. The intent is to close the “speed gap” where attackers can reuse newly exposed credentials faster than responders can scope, reset, and clean up.
This capability is available as an out-of-the-box enhancement for Microsoft Defender for Endpoint P2 customers who meet the Microsoft Defender prerequisites.
The following section revisits a real-world domain compromise that showcases how attack disruption and predictive shielding changed the outcome by acting on exposure, rather than just observed abuse. Interestingly, this case happened just as we’re rolling out the predictive shielding, so you can see the changes in both attacker tradecraft and the detection and response actions before and after this capability was deployed.
Attack chain overview
In June 2025, a public sector organization was targeted by a threat actor. This threat actor progressed methodically: initial exploitation, local escalation, directory reconnaissance, credential access, and expansion into Microsoft Exchange and identity infrastructure.
Figure 1. Attack diagram of the domain compromise.
Initial entry: Pre-domain compromise
The campaign began at the edge: a file-upload flaw in an internet-facing Internet Information Services (IIS) server was abused to plant and launch a web shell. The attacker then simultaneously performed various reconnaissance activities using the compromised account through the web shell and escalated their privileges to NT AUTHORITY\SYSTEM by abusing a Potato-class token impersonation primitive (for example, BadPotato).
The discovery commands observed in the attack include the following example:
Using the compromised IIS service account, the attacker attempted to reset the passwords of high-impact identities, a common technique used to gain control over accounts without performing credential dumping. The attacker also deployed Mimikatz to dump logon secrets (for example, MSV, LSASS, and SAM), harvesting credentials that are exposed on the device.
Had predictive shielding been released at this point, automated restrictions on exposed accounts could have stopped the intrusion before it expanded beyond the single-host foothold. However, at the time of the incident, this capability hasn’t been deployed to customers yet.
Key takeaway: At this stage of an attack, it’s important to keep the containment host‑scoped. Defenders should prioritize blocking credential theft and stopping escalation before it reaches the identity infrastructure.
First pivot: Directory credential materialization and Exchange delegation
Within 24 hours, the attacker abused privileged accounts and remotely created a scheduled task on a domain controller. The task initiated NTDS snapshot activity and packaged the output using makecab.exe, enabling offline access to directory credential material that’s suitable for abusing credentials at scale:
Because the first malicious action by the abused account already surfaced the entire Active Directory credentials, stopping its path for total domain compromise was no longer feasible.
The threat actor then planted a Godzilla web shell on Exchange Server, used a privileged context to enumerate accounts with ApplicationImpersonation role assignments, and granted full access to a delegated principal across mailboxes using Add‑MailboxPermission. This access allowed the threat actor to read and manipulate all mailbox contents.
The attack also used Impacket’s atexec.py to enumerate the role assignments remotely. Its use triggered the attack disruption capability in Defender, revoking the account sessions of an admin account and blocking it from further use.
Following the abused account’s disruption, the attacker attempted several additional actions, such as resetting the disrupted account’s and other accounts’ passwords. They also attempted to dump credentials of a Veeam backup device.
Key takeaway: This pivot is a turning point. Once directory credentials and privileged delegation are in play, the scope and impact of an incident expand fast. Defenders should prioritize protecting domain controllers, privileged identities, and authentication paths.
Scale and speed: Tool return, spraying, and lateral movement
Weeks later, the threat actor returned with an Impacket tooling (for example, secretsdump and PsExec) that resulted in repeated disruptions by Defender against the abused accounts that they used. These disruptions forced the attacker to pivot to other compromised accounts and exhaust their resources.
Following Defender’s disruptions, the threat actor then launched a broad password spray from the initially compromised IIS server, unlocking access to at least 14 servers through password reuse. They also attempted remote credential dumping against a couple of domain controllers and an additional IIS server using multiple domain and service principals.
Key takeaway: Even though automatic attack disruption acted right away, the attacker already possessed multiple credentials due to the previous large-scale credential dumping. This scenario showcases the race to detect and disrupt credential abuse and is the reason we’re introducing predictive shielding to preemptively disrupt exposed accounts at risk.
Predictive shielding breaks the chain: Exposure-centric containment
In the second phase of the attack, we activated predictive shielding. When exposure signals surfaced (for example, credential dumping attempts and replay from compromised hosts), automated containment blocked new sign-in attempts and interactive pivots not only for the abused accounts, but also for context-linked identities that are active on the same compromised surfaces.
Attack disruption contained high-privileged principals to prevent these accounts from being abused. Crucially, when a high-tier Enterprise or Schema Admin credential was exposed, predictive shielding contained it pre-abuse, preventing what would normally become a catastrophic escalation.
Second pivot: Alternative paths to new credentials
With high-value identities pre-contained, the threat actor pivoted to exploiting Apache Tomcat servers. They compromised three Tomcat servers, dropped the Godzilla web shell, and launched the PowerShell-based Invoke-Mimikatz command to harvest additional credentials. At one point, the attacker operated under Schema Admin:
They then used Impacket WmiExec to access Microsoft Entra Connect servers and attempt to extract Entra Connect synchronization credentials. The account used for this pivot was later contained, limiting further lateral movement.
Last attempts and shutdown
In the final phase of the attack, the threat actor attempted a full LSASS dump on a file sharing server using comsvcs.dll MiniDump under a domain user account, followed by additional NTDS activity:
Attack disruption in Defender repeatedly severed sessions and blocked new sign-ins made by the threat actor. On July 28, 2025, the attack campaign lost momentum and stopped.
How predictive shielding changed the outcome
Before compromising a domain, attackers are mostly constrained by the hosts they control. However, even a small set of exposed credentials could remove their constraints and give them broad access through privileged authentication and delegated pathways. The blast radius spreads fast, time pressure spikes, and containment decisions become riskier because identity infrastructure and high-privilege accounts are production dependencies.
The incident we revisited earlier almost followed a similar pattern. It unfolded while predictive shielding was still being launched, so the automated predictive containment capability only became active at the midway of the attack campaign. During the attack’s first stages, the threat actor had room to scale—they returned with new tooling, launched a broad password spray attack, and expanded access across multiple servers. They also attempted remote credential dumping against domain controllers and servers.
When predictive shielding went live, it helped shift the story and we then saw the change of pace—instead of reacting to each newly abused account, the capability allowed Defender to act preemptively and turn credential theft attempts into blocked pivots. Defender was able to block new sign-ins and interactive pivots, not just for the single abused account, but also for context-linked identities that were active on the same compromised surfaces.
With high-value identities pre-contained, the adversary shifted tradecraft and chased other credential sources, but each of their subsequent attempts triggered targeted containment that limited their lateral reach until they lost momentum and stopped. How this incident concluded is the operational “tell” that containment is working, in that once privileged pivots get blocked, threat actors often hunt for alternate credential sources, and defenses must continue following the moving blast radius.
As predictive shielding matures, it will continue to expand its prediction logic and context-linked identities.
MITRE ATT&CK® techniques observed
The following table maps observed behaviors to ATT&CK®.
Tactics shown are per technique definition.
Tactic(s)
Technique ID
Technique name
Observed details
Initial Access
T1190
Exploit Public-Facing Application
Exploited a file-upload vulnerability in an IIS server to drop a web shell.
Persistence
T1505.003
Server Software Component: Web Shell
Deployed web shells for persistent access.
Execution
T1059.001
Command and Scripting Interpreter: PowerShell
Used PowerShell for Exchange role queries, mailbox permission changes, and Invoke-Mimikatz.
Privilege Escalation
T1068
Exploitation for Privilege Escalation
Used BadPotato to escalate to SYSTEM on an IIS server.
Credential Access
T1003.001
OS Credential Dumping: LSASS Memory
Dumped LSASS using Mimikatz and comsvcs.dll MiniDump.
Credential Access
T1003.003
OS Credential Dumping: NTDS
Performed NTDS-related activity using ntdsutil snapshot/IFM workflows on a domain controller.
Execution; Persistence; Privilege Escalation
T1053.005
Scheduled Task/Job: Scheduled Task
Created remote scheduled tasks to execute under SYSTEM on a domain controller.
Discovery
T1087.002
Account Discovery: Domain Account
Enumerated domain groups and accounts using net group and AD Explorer.
Lateral Movement
T1021.002
Remote Services: SMB/Windows Admin Shares
Used admin shares/SMB-backed tooling (for example, PsExec) for lateral movement.
Lateral Movement
T1021.003
Remote Services: Windows Remote Management
Used WmiExec against Microsoft Entra Connect servers.
Credential Access
T1110.003
Brute Force: Password Spraying
Performed password spraying leading to access across at least 14 servers.
Collection
T1114.002
Email Collection: Remote Email Collection
Expanded mailbox access broadly through impersonation or permission changes.
Command and Control
T1071.001
Application Layer Protocol: Web Protocols
Web shells communicated over HTTP/S.
Defense Evasion
T1070.004
Indicator Removal on Host: File Deletion
Used cleanup scripts (for example, del.bat) to remove dump artifacts.
Persistence; Privilege Escalation
T1098
Account Manipulation
Manipulated permissions and roles to expand access and sustain control.
Credential Access
T1078
Valid Accounts
Reused compromised service and domain accounts for access and lateral movement.
Learn more
For more information about automatic attack disruption and predictive shielding, see the following Microsoft Learn articles:
Check out our latest Ninja show showcasing how predictive shielding expands to identity centric attacks
Microsoft Threat Intelligence uncovered a macOS‑focused cyber campaign by the North Korean threat actor Sapphire Sleet that relies on social engineering rather than software vulnerabilities. By impersonating a legitimate software update, threat actors tricked users into manually running malicious files, allowing them to steal passwords, cryptocurrency assets, and personal data while avoiding built‑in macOS security checks. This activity highlights how convincing user prompts and trusted system tools can be abused, and why awareness and layered security defenses remain critical.
Microsoft Threat Intelligence identified a campaign by North Korean state actor Sapphire Sleet demonstrating new combinations of macOS-focused execution patterns and techniques, enabling the threat actor to compromise systems through social engineering rather than software exploitation. In this campaign, Sapphire Sleet takes advantage of user‑initiated execution to establish persistence, harvest credentials, and exfiltrate sensitive data while operating outside traditional macOS security enforcement boundaries. While the techniques themselves are not novel, this analysis highlights execution patterns and combinations that Microsoft has not previously observed for this threat actor, including how Sapphire Sleet orchestrates these techniques together and uses AppleScript as a dedicated, late‑stage credential‑harvesting component integrated with decoy update workflows.
After discovering the threat, Microsoft shared details of this activity with Apple as part of our responsible disclosure process. Apple has since implemented updates to help detect and block infrastructure and malware associated with this campaign. We thank the Apple security team for their collaboration in addressing this activity and encourage macOS users to keep their devices up to date with the latest security protections.
This activity demonstrates how threat actors continue to rely on user interaction and trusted system utilities to bypass macOS platform security protections, rather than exploiting traditional software vulnerabilities. By persuading users to manually execute AppleScript or Terminal‑based commands, Sapphire Sleet shifts execution into a user‑initiated context, allowing the activity to proceed outside of macOS protections such as Transparency, Consent, and Control (TCC), Gatekeeper, quarantine enforcement, and notarization checks. Sapphire Sleet achieves a highly reliable infection chain that lowers operational friction and increases the likelihood of successful compromise—posing an elevated risk to organizations and individuals involved in cryptocurrency, digital assets, finance, and similar high‑value targets that Sapphire Sleet is known to target.
In this blog, we examine the macOS‑specific attack chain observed in recent Sapphire Sleet intrusions, from initial access using malicious .scpt files through multi-stage payload delivery, credential harvesting using fake system dialogs, manipulation of the macOS TCC database, persistence using launch daemons, and large-scale data exfiltration. We also provide actionable guidance, Microsoft Defender detections, hunting queries, and indicators of compromise (IOCs) to help defenders identify similar threats and strengthen macOS security posture.
Sapphire Sleet’s campaign lifecycle
Initial access and social engineering
Sapphire Sleet is a North Korean state actor active since at least March 2020 that primarily targets the finance sector, including cryptocurrency, venture capital, and blockchain organizations. The primary motivation of this actor is to steal cryptocurrency wallets to generate revenue, and target technology or intellectual property related to cryptocurrency trading and blockchain platforms.
Recent campaigns demonstrate expanded execution mechanisms across operating systems like macOS, enabling Sapphire Sleet to target a broader set of users through parallel social engineering workflows.
Sapphire Sleet operates a well‑documented social engineering playbook in which the threat actor creates fake recruiter profiles on social media and professional networking platforms, engages targets in conversations about job opportunities, schedules a technical interview, and directs targets to install malicious software, which is typically disguised as a video conferencing tool or software developer kit (SDK) update.
In this observed activity, the target was directed to download a file called Zoom SDK Update.scpt—a compiled AppleScript that opens in macOS Script Editor by default. Script Editor is a trusted first-party Apple application capable of executing arbitrary shell commands using the do shell script AppleScript command.
Lure file and Script Editor execution
Figure 1. Initial access: The .scpt lure file as seen in macOS Script Editor
The malicious Zoom SDK Update.scpt file is crafted to appear as a legitimate Zoom SDK update when opened in the macOS Script Editor app, beginning with a large decoy comment block that mimics benign upgrade instructions and gives the impression of a routine software update. To conceal its true behavior, the script inserts thousands of blank lines immediately after this visible content, pushing the malicious logic far below the scrollable view of the Script Editor window and reducing the likelihood that a user will notice it.
Hidden beneath this decoy, the script first launches a harmless looking command that invokes the legitimate macOS softwareupdate binary with an invalid parameter, an action that performs no real update but launches a trusted Apple‑signed process to reinforce the appearance of legitimacy. Following this, the script executes its malicious payload by using curl to retrieve threat actor‑controlled content and immediately passes the returned data to osascript for execution using the run script result instruction. Because the content fetched by curl is itself a new AppleScript, it is launched directly within the Script Editor context, initiating a payload delivery in which additional stages are dynamically downloaded and executed.
Figure 2. The AppleScript lure with decoy content and payload execution
Execution and payload delivery
Cascading curl-to-osascript execution
When the user opens the Zoom SDK Update.scpt file, macOS launches the file in Script Editor, allowing Sapphire Sleet to transition from a single lure file to a multi-stage, dynamically fetched payload chain. From this single process, the entire attack unfolds through a cascading chain of curl commands, each fetching and executing progressively more complex AppleScript payloads. Each stage uses a distinct user-agent string as a campaign tracking identifier.
Figure 3. Process tree showing cascading execution from Script Editor
The main payload fetched by the mac-cur1 user agent is the attack orchestrator. Once executed within the Script Editor, it performs immediate reconnaissance, then kicks off parallel operations using additional curl commands with different user-agent strings.
Note the URL path difference: mac-cur1 through mac-cur3 fetch from /version/ (AppleScript payloads piped directly to osascript for execution), while mac-cur4 and mac-cur5 fetch from /status/ (ZIP archives containing compiled macOS .app bundles).
The following table summarizes the curl chain used in this campaign.
User agent
URL path
Purpose
mac-cur1
/fix/mac/update/version/
Main orchestrator (piped to osascript) beacon. Downloads com.apple.cli host monitoringcomponent and services backdoor
mac-cur2
/fix/mac/update/version/
Invokes curl with mac-cur4 which downloads credential harvester systemupdate.app
mac-cur3
/fix/mac/update/version/
TCC bypass + data collection + exfiltration (wallets, browser, keychains, history, Apple Notes, Telegram)
Figure 4. The curl chain showing user-agent strings and payload routing
Reconnaissance and C2 registration
After execution, the malware next identifies and registers the compromised device with Sapphire Sleet infrastructure. The malware starts by collecting basic system details such as the current user, host name, system time, and operating system install date. This information is used to uniquely identify the compromised device and track subsequent activity.
The malware then registers the compromised system with its command‑and‑control (C2) infrastructure. The mid value represents the device’s universally unique identifier (UUID), the did serves as a campaign‑level tracking identifier, and the user field combines the system host name with the device serial number to uniquely label the targeted user.
Figure 5. C2 registration with device UUID and campaign identifier
Host monitoring component: com.apple.cli
The first binary deployed is a host monitoring component called com.apple.cli—a ~5 MB Mach-O binary disguised with an Apple-style naming convention.
The mac-cur1 payload spawns an osascript that downloads and launches com.apple.cli:
Figure 6. com.apple.cli deployment using osascript
The host monitoring component repeatedly executes a series of system commands to collect environment and runtime information, including the macOS version (sw_vers), the current system time (date -u), and the underlying hardware model (sysctl hw.model). It then runs ps aux in a tight loop to capture a full, real‑time list of running processes.
During execution, com.apple.cli performs host reconnaissance while maintaining repeated outbound connectivity to the threat actor‑controlled C2 endpoint 83.136.208[.]246:6783. The observed sequencing of reconnaissance activity and network communication is consistent with staging for later operational activity, including privilege escalation, and exfiltration.
In parallel with deploying com.apple.cli, the mac-cur1 orchestrator also deploys a second component, the services backdoor, as part of the same execution flow; its role in persistence and follow‑on activity is described later in this blog.
Credential access
Credential harvester: systemupdate.app
After performing reconnaissance, the mac-cur1 orchestrator begins parallel operations. During the mac‑cur2 stage of execution (independent from the mac-cur1 stage), Sapphire Sleet delivers an AppleScript payload that is executed through osascript. This stage is responsible for deploying the credential harvesting component of the attack.
Before proceeding, the script checks for the presence of a file named .zoom.log on the system. This file acts as an infection marker, allowing Sapphire Sleet to determine whether the device has already been compromised. If the marker exists, deployment is skipped to avoid redundant execution across sessions.
If the infection marker is not found, the script downloads a compressed archive through the mac-cur4 user agent that contains a malicious macOS application named (systemupdate.app), which masquerades as the legitimate system update utility by the same name. The archive is extracted to a temporary location, and the application is launched immediately.
When systemupdate.app launches, the user is presented with a native macOS password dialog that is visually indistinguishable from a legitimate system prompt. The dialog claims that the user’s password is required to complete a software update, prompting the user to enter their credentials.
After the user enters their password, the malware performs two sequential actions to ensure the credential is usable and immediately captured. First, the binary validates the entered password against the local macOS authentication database using directory services, confirming that the credential is correct and not mistyped. Once validation succeeds, the verified password is immediately exfiltrated to threat actor‑controlled infrastructure using the Telegram Bot API, delivering the stolen credential directly to Sapphire Sleet.
Figure 7. Password popup given by fake systemupdate.app
Decoy completion prompt: softwareupdate.app
After credential harvesting is completed using systemupdate.app, Sapphire Sleet deploys a second malicious application named softwareupdate.app, whose sole purpose is to reinforce the illusion of a legitimate update workflow. This application is delivered during a later stage of the attack using the mac‑cur5 user‑agent. Unlike systemupdate.app, softwareupdate.app does not attempt to collect credentials. Instead, it displays a convincing “system update complete” dialog to the user, signaling that the supposed Zoom SDK update has finished successfully. This final step closes the social engineering loop: the user initiated a Zoom‑themed update, was prompted to enter their password, and is now reassured that the process completed as expected, reducing the likelihood of suspicion or further investigation.
Persistence
Primary backdoor and persistence installer: services binary
The services backdoor is a key operational component in this attack, acting as the primary backdoor and persistence installer. It provides an interactive command execution channel, establishes persistence using a launch daemon, and deploys two additional backdoors. The services backdoor is deployed through a dedicated AppleScript executed as part of the initial mac‑cur1 payload that also deployed com.apple.cli, although the additional backdoors deployed by services are executed at a later stage.
During deployment, the services backdoor binary is first downloaded using a hidden file name (.services) to reduce visibility, then copied to its final location before the temporary file is removed. As part of installation, the malware creates a file named auth.db under ~/Library/Application Support/Authorization/, which stores the path to the deployed services backdoor and serves as a persistent installation marker. Any execution or runtime errors encountered during this process are written to /tmp/lg4err, leaving behind an additional forensic artifact that can aid post‑compromise investigation.
Figure 8. Services backdoor deployment using osascript
Unlike com.apple.cli, the services backdoor uses interactive zsh shells (/bin/zsh -i) to execute privileged operations. The -i flag creates an interactive terminal context, which is required for sudo commands that expect interactive input.
Figure 9. Interactive zsh shell execution by the services backdoor
Additional backdoors: icloudz and com.google.chromes.updaters
Of the additional backdoors deployed by services, the icloudz backdoor is a renamed copy of the previously deployed services backdoor and shares the same SHA‑256 hash, indicating identical underlying code. Despite this, it is executed using a different and more evasive technique. Although icloudz shares the same binary as .services, it operates as a reflective code loader—it uses the macOS NSCreateObjectFileImageFromMemory API to load additional payloads received from its C2 infrastructure directly into memory, rather than writing them to disk and executing them conventionally.
The icloudz backdoor is stored at ~/Library/Application Support/iCloud/icloudz, a location and naming choice intended to resemble legitimate iCloud‑related artifacts. Once loaded into memory, two distinct execution waves are observed. Each wave independently initializes a consistent sequence of system commands: existing caffeinate processes are stopped, caffeinate is relaunched using nohup to prevent the system from sleeping, basic system information is collected using sw_vers and sysctl -n hw.model, and an interactive /bin/zsh -i shell is spawned. This repeated initialization suggests that the component is designed to re‑establish execution context reliably across runs.
From within the interactive zsh shell, icloudz deploys an additional (tertiary) backdoor, com.google.chromes.updaters, to disk at ~/Library/Google/com.google.chromes.updaters. The selected directory and file name closely resemble legitimate Google application data, helping the file blend into the user’s Home directory and reducing the likelihood of casual inspection. File permissions are adjusted; ownership is set to allow execution with elevated privileges, and the com.google.chromes.updaters binary is launched using sudo.
To ensure continued execution across reboots, a launch daemon configuration file named com.google.webkit.service.plist is installed under /Library/LaunchDaemons. This configuration causes icloudz to launch automatically at system startup, even if no user is signed in. The naming convention deliberately mimics legitimate Apple and Google system services, further reducing the chance of detection.
The com.google.chromes.updaters backdoor is the final and largest component deployed in this attack chain, with a size of approximately 7.2 MB. Once running, it establishes outbound communication with threat actor‑controlled infrastructure, connecting to the domain check02id[.]com over port 5202. The process then enters a precise 60‑second beaconing loop. During each cycle, it executes minimal commands such as whoami to confirm the execution context and sw_vers -productVersion to report the operating system version. This lightweight heartbeat confirms the process remains active, is running with elevated privileges, and is ready to receive further instructions.
Privilege escalation
TCC bypass: Granting AppleEvents permissions
Before large‑scale data access and exfiltration can proceed, Sapphire Sleet must bypass macOS TCC protections. TCC enforces user consent for sensitive inter‑process interactions, including AppleEvents, the mechanism required for osascript to communicate with Finder and perform file-level operations. The mac-cur3 stage silently grants itself these permissions by directly manipulating the user-level TCC database through the following sequence.
The user-level TCC database (~/Library/Application Support/com.apple.TCC/TCC.db) is itself TCC-protected—processes without Full Disk Access (FDA) cannot read or modify it. Sapphire Sleet circumvents this by directing Finder, which holds FDA by default on macOS, to rename the com.apple.TCC folder. Once renamed, the TCC database file can be copied to a staging location by a process without FDA.
Sapphire Sleet then uses sqlite3 to inject a new entry into the database’s access table. This entry grants /usr/bin/osascript permission to send AppleEvents to com.apple.finder and includes valid code-signing requirement (csreq) blobs for both binaries, binding the grant to Apple-signed executables. The authorization value is set to allowed (auth_value=2) with a user-set reason (auth_reason=3), ensuring no user prompt is triggered. The modified database is then copied back into the renamed folder, and Finder restores the folder to its original name. Staging files are deleted to reduce forensic traces.
Figure 10. Overwriting original TCC database with modified version
Collection and exfiltration
With TCC bypassed, credentials stolen, and backdoors deployed, Sapphire Sleet launches the next phase of attack: a 575-line AppleScript payload that systematically collects, stages, compresses, and exfiltrates seven categories of data.
Exfiltration architecture
Every upload follows a consistent pattern and is executed using nohup, which allows the command to continue running in the background even if the initiating process or Terminal session exits. This ensures that data exfiltration can complete reliably without requiring the threat actor to maintain an active session on the system.
The auth header provides the upload authorization token, and the mid header ties the upload to the compromised device’s UUID.
Figure 11. Exfiltration upload pattern with nohup
Data collected during exfiltration
Host and system reconnaissance: Before bulk data collection begins, the script records basic system identity and hardware information. This includes the current username, system host name, macOS version, and CPU model. These values are appended to a per‑host log file and provide Sapphire Sleet with environmental context, hardware fingerprinting, and confirmation of the target system’s characteristics. This reconnaissance data is later uploaded to track progress and correlate subsequent exfiltration stages to a specific device.
Installed applications and runtime verification: The script enumerates installed applications and shared directories to build an inventory of the system’s software environment. It also captures a live process listing filtered for threat actor‑deployed components, allowing Sapphire Sleet to verify that earlier payloads are still running as expected. These checks help confirm successful execution and persistence before proceeding further.
Messaging session data (Telegram): Telegram Desktop session data is collected by copying the application’s data directories, including cryptographic key material and session mapping files. These artifacts are sufficient to recreate the user’s Telegram session on another system without requiring reauthentication. A second collection pass targets the Telegram App Group container to capture the complete local data set associated with the application.
Browser data and extension storage: For Chromium‑based browsers, including Chrome, Brave, and Arc, the script copies browser profiles and associated databases. This includes saved credentials, cookies, autofill data, browsing history, bookmarks, and extension‑specific storage. Particular focus is placed on IndexedDB entries associated with cryptocurrency wallet extensions, where wallet keys and transaction data are stored. Only IndexedDB entries matching a targeted set of wallet extension identifiers are collected, reflecting a deliberate and selective approach.
macOS keychain: The user’s sign-in keychain database is bundled alongside browser data. Although the keychain is encrypted, Sapphire Sleet has already captured the user’s password earlier in the attack chain, enabling offline decryption of stored secrets once exfiltrated.
Cryptocurrency desktop wallets: The script copies the full application support directories for popular cryptocurrency desktop wallets, including Ledger Live and Exodus. These directories contain wallet configuration files and key material required to access stored cryptocurrency assets, making them high‑value targets for exfiltration.
SSH keys and shell history: SSH key directories and shell history files are collected to enable potential lateral movement and intelligence gathering. SSH keys may provide access to additional systems, while shell history can reveal infrastructure details, previously accessed hosts, and operational habits of the targeted user.
Apple Notes: The Apple Notes database is copied from its application container and staged for upload. Notes frequently contain sensitive information such as passwords, internal documentation, infrastructure details, or meeting notes, making them a valuable secondary data source.
System logs and failed access attempts: System log files are uploaded directly without compression. These logs provide additional hardware and execution context and include progress markers that indicate which exfiltration stages have completed. Failed collection attempts—such as access to password manager containers that are not present on the system—are also recorded and uploaded, allowing Sapphire Sleet to understand which targets were unavailable on the compromised host.
Exfiltration summary
#
Data category
ZIP name
Upload port
Estimated sensitivity
1
Telegram session
tapp_<user>.zip
8443
Critical — session hijack
2
Browser data + Keychain
ext_<user>.zip
8443
Critical — all passwords
3
Ledger wallet
ldg_<user>.zip
8443
Critical — crypto keys
4
Exodus wallet
exds_<user>.zip
8443
Critical — crypto keys
5
SSH + shell history
hs_<user>.zip
8443
High — lateral movement
6
Apple Notes
nt_<user>.zip
8443
Medium-High
7
System log
lg_<user> (no zip)
8443
Low — fingerprinting
8
Recon log
flog (no zip)
8443
Low — inventory
9
Credentials
Telegram message
443 (Telegram API)
Critical — sign-in password
All uploads use the upload authorization token fwyan48umt1vimwqcqvhdd9u72a7qysi and the machine identifier 82cf5d92-87b5-4144-9a4e-6b58b714d599.
Defending against Sapphire Sleet intrusion activity
As part of a coordinated response to this activity, Apple has implemented platform-level protections to help detect and block infrastructure and malware associated with this campaign. Apple has deployed Apple Safe Browsing protections in Safari to detect and block malicious infrastructure associated with this campaign. Users browsing with Safari benefit from these protections by default. Apple has also deployed XProtect signatures to detect and block the malware families associated with this campaign—macOS devices receive these signature updates automatically.
Microsoft recommends the following mitigation steps to defend against this activity and reduce the impact of this threat:
Educate users about social engineering threats originating from social media and external platforms, particularly unsolicited outreach requesting software downloads, virtual meeting tool installations, or execution of terminal commands. Users should never run scripts or commands shared through messages, calls, or chats without prior approval from their IT or security teams.
Block or restrict the execution of .scpt (compiled AppleScript) files and unsigned Mach-O binaries downloaded from the internet. Where feasible, enforce policies that prevent osascript from executing scripts sourced from external locations.
Always inspect and verify files downloaded from external sources, including compiled AppleScript (.scpt) files. These files can execute arbitrary shell commands via macOS Script Editor—a trusted first-party Apple application—making them an effective and stealthy initial access vector.
Limit or audit the use of curl piped to interpreters (such as curl | osascript, curl | sh, curl | bash). Social engineering campaigns by Sapphire Sleet rely on cascading curl-to-interpreter chains to avoid writing payloads to disk. Organizations should monitor for and restrict piped execution patterns originating from non-standard user-agent strings.
Exercise caution when copying and pasting sensitive data such as wallet addresses or credentials from the clipboard. Always verify that the pasted content matches the intended source to avoid falling victim to clipboard hijacking or data tampering attacks.
Monitor for unauthorized modifications to the macOS TCC database. This campaign manipulates TCC.db to grant AppleEvents permissions to osascript without user consent—a prerequisite for the large-scale data exfiltration phase. Look for processes copying, modifying, or overwriting ~/Library/Application Support/com.apple.TCC/TCC.db.
Audit LaunchDaemon and LaunchAgent installations. This campaign installs a persistent launch daemon (com.google.webkit.service.plist) that masquerades as a legitimate Google or Apple service. Monitor /Library/LaunchDaemons/ and ~/Library/LaunchAgents/ for unexpected plist files, particularly those with com.google.* or com.apple.* naming conventions not belonging to genuine vendor software.
Protect cryptocurrency wallets and browser credential stores. This campaign targets nine specific crypto wallet extensions (Sui, Phantom, TronLink, Coinbase, OKX, Solflare, Rabby, Backpack) plus Bitwarden, and exfiltrates browser sign-in data, cookies, and keychain databases. Organizations handling digital assets should enforce hardware wallet policies and rotate browser-stored credentials regularly.
Encourage users to use web browsers that support Microsoft Defender SmartScreen like Microsoft Edge—available on macOS and various platforms—which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that contain exploits and host malware.
Microsoft Defender for Endpoint customers can also apply the following mitigations to reduce the environmental attack surface and mitigate the impact of this threat and its payloads:
Turn on cloud-delivered protection and automatic sample submission on Microsoft Defender Antivirus. These capabilities use artificial intelligence and machine learning to quickly identify and stop new and unknown threats.
Enable potentially unwanted application (PUA) protection in block mode to automatically quarantine PUAs like adware. PUA blocking takes effect on endpoint clients after the next signature update or computer restart.
Turn on network protection to block connections to malicious domains and IP addresses.
Microsoft Defender detection 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 – Enumeration of files with sensitive data – Suspicious File Copy Operations Using CoreUtil – Suspicious archive creation – Remote exfiltration activity – Possible exfiltration of archived data
Command and control
– Mach-O backdoors beaconing to C2 (com.apple.cli, services, com.google.chromes.updaters)
Microsoft Defender Antivirus – Trojan:MacOS/NukeSped.D – Backdoor:MacOS/FlowOffset.B!dha – Backdoor:MacOS/FlowOffset.C!dha
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.
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.
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:
Suspicious osascript execution with curl piping
Search for curl commands piping output directly to osascript, a core technique in this Sapphire Sleet campaign’s cascading payload delivery chain.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where FileName == "osascript" or InitiatingProcessFileName == "osascript"
| where ProcessCommandLine has "curl" and ProcessCommandLine has_any ("osascript", "| sh", "| bash")
| project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessCommandLine, InitiatingProcessFileName
Suspicious curl activity with campaign user-agent strings
Search for curl commands using user-agent strings matching the Sapphire Sleet campaign tracking identifiers (mac-cur1 through mac-cur5, audio, beacon).
DeviceProcessEvents
| where Timestamp > ago(30d)
| where FileName == "curl" or ProcessCommandLine has "curl"
| where ProcessCommandLine has_any ("mac-cur1", "mac-cur2", "mac-cur3", "mac-cur4", "mac-cur5", "-A audio", "-A beacon")
| project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine
Detect connectivity with known C2 infrastructure
Search for network connections to the Sapphire Sleet C2 domains and IP addresses used in this campaign.
let c2_domains = dynamic(["uw04webzoom.us", "uw05webzoom.us", "uw03webzoom.us", "ur01webzoom.us", "uv01webzoom.us", "uv03webzoom.us", "uv04webzoom.us", "ux06webzoom.us", "check02id.com"]);
let c2_ips = dynamic(["188.227.196.252", "83.136.208.246", "83.136.209.22", "83.136.208.48", "83.136.210.180", "104.145.210.107"]);
DeviceNetworkEvents
| where Timestamp > ago(30d)
| where RemoteUrl has_any (c2_domains) or RemoteIP in (c2_ips)
| project Timestamp, DeviceId, DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName, InitiatingProcessCommandLine
TCC database manipulation detection
Search for processes that copy, modify, or overwrite the macOS TCC database, a key defense evasion technique used by this campaign to grant unauthorized AppleEvents permissions.
DeviceFileEvents
| where Timestamp > ago(30d)
| where FolderPath has "com.apple.TCC" and FileName == "TCC.db"
| where ActionType in ("FileCreated", "FileModified", "FileRenamed")
| project Timestamp, DeviceId, DeviceName, ActionType, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine
Suspicious LaunchDaemon creation masquerading as legitimate services
Search for LaunchDaemon plist files created in /Library/LaunchDaemons that masquerade as Google or Apple services, matching the persistence technique used by the services/icloudz backdoor.
DeviceFileEvents
| where Timestamp > ago(30d)
| where FolderPath startswith "/Library/LaunchDaemons/"
| where FileName startswith "com.google." or FileName startswith "com.apple."
| where ActionType == "FileCreated"
| project Timestamp, DeviceId, DeviceName, FileName, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine, SHA256
Malicious binary execution from suspicious paths
Search for execution of binaries from paths commonly used by Sapphire Sleet, including hidden Library directories, /private/tmp/, and user-specific Application Support folders.
Credential harvesting using dscl authentication check
Search for dscl -authonly commands used by the fake password dialog (systemupdate.app) to validate stolen credentials before exfiltration.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where FileName == "dscl" or ProcessCommandLine has "dscl"
| where ProcessCommandLine has "-authonly"
| project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine
Telegram Bot API exfiltration detection
Search for network connections to Telegram Bot API endpoints, used by this campaign to exfiltrate stolen credentials.
DeviceNetworkEvents
| where Timestamp > ago(30d)
| where RemoteUrl has "api.telegram.org" and RemoteUrl has "/bot"
| project Timestamp, DeviceId, DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName, InitiatingProcessCommandLine
Reflective code loading using NSCreateObjectFileImageFromMemory
Search for evidence of reflective Mach-O loading, the technique used by the icloudz backdoor to execute code in memory.
DeviceEvents
| where Timestamp > ago(30d)
| where ActionType has "NSCreateObjectFileImageFromMemory"
or AdditionalFields has "NSCreateObjectFileImageFromMemory"
| project Timestamp, DeviceId, DeviceName, ActionType, FileName, FolderPath, InitiatingProcessFileName, AdditionalFields
Suspicious caffeinate and sleep prevention activity
Search for caffeinate process stop-and-restart patterns used by the services and icloudz backdoors to prevent the system from sleeping during backdoor operations.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where ProcessCommandLine has "caffeinate"
| where InitiatingProcessCommandLine has_any ("icloudz", "services", "chromes.updaters", "zsh -i")
| project Timestamp, DeviceId, DeviceName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine
Detect known malicious file hashes
Search for the specific malicious file hashes associated with this Sapphire Sleet campaign across file events.
let malicious_hashes = dynamic([
"2075fd1a1362d188290910a8c55cf30c11ed5955c04af410c481410f538da419",
"05e1761b535537287e7b72d103a29c4453742725600f59a34a4831eafc0b8e53",
"5fbbca2d72840feb86b6ef8a1abb4fe2f225d84228a714391673be2719c73ac7",
"5e581f22f56883ee13358f73fabab00fcf9313a053210eb12ac18e66098346e5",
"95e893e7cdde19d7d16ff5a5074d0b369abd31c1a30962656133caa8153e8d63",
"8fd5b8db10458ace7e4ed335eb0c66527e1928ad87a3c688595804f72b205e8c",
"a05400000843fbad6b28d2b76fc201c3d415a72d88d8dc548fafd8bae073c640"
]);
DeviceFileEvents
| where Timestamp > ago(30d)
| where SHA256 in (malicious_hashes)
| project Timestamp, DeviceId, DeviceName, FileName, FolderPath, SHA256, ActionType, InitiatingProcessFileName, InitiatingProcessCommandLine
Data staging and exfiltration activity
Search for ZIP archive creation in /tmp/ directories followed by curl uploads matching the staging-and-exfiltration pattern used for browser data, crypto wallets, Telegram sessions, SSH keys, and Apple Notes.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where (ProcessCommandLine has "zip" and ProcessCommandLine has "/tmp/")
or (ProcessCommandLine has "curl" and ProcessCommandLine has_any ("tapp_", "ext_", "ldg_", "exds_", "hs_", "nt_", "lg_"))
| project Timestamp, DeviceId, DeviceName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine
Search for Script Editor (the default handler for .scpt files) spawning curl, osascript, or shell commands—the initial execution vector in this campaign.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where InitiatingProcessFileName == "Script Editor" or InitiatingProcessCommandLine has "Script Editor"
| where FileName has_any ("curl", "osascript", "sh", "bash", "zsh")
| project Timestamp, DeviceId, DeviceName, FileName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine
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 indicators of compromise
The following query checks for connections to the Sapphire Sleet C2 domains and IP addresses across network session data:
let lookback = 30d;
let ioc_domains = dynamic(["uw04webzoom.us", "uw05webzoom.us", "uw03webzoom.us", "ur01webzoom.us", "uv01webzoom.us", "uv03webzoom.us", "uv04webzoom.us", "ux06webzoom.us", "check02id.com"]);
let ioc_ips = dynamic(["188.227.196.252", "83.136.208.246", "83.136.209.22", "83.136.208.48", "83.136.210.180", "104.145.210.107"]);
DeviceNetworkEvents
| where TimeGenerated > ago(lookback)
| where RemoteUrl has_any (ioc_domains) or RemoteIP in (ioc_ips)
| summarize EventCount=count() by DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName
Detect file hash indicators of compromise
The following query searches for the known malicious file hashes associated with this campaign across file, process, and security event data:
let selectedTimestamp = datetime(2026-01-01T00:00:00.0000000Z);
let FileSHA256 = dynamic([
"2075fd1a1362d188290910a8c55cf30c11ed5955c04af410c481410f538da419",
"05e1761b535537287e7b72d103a29c4453742725600f59a34a4831eafc0b8e53",
"5fbbca2d72840feb86b6ef8a1abb4fe2f225d84228a714391673be2719c73ac7",
"5e581f22f56883ee13358f73fabab00fcf9313a053210eb12ac18e66098346e5",
"95e893e7cdde19d7d16ff5a5074d0b369abd31c1a30962656133caa8153e8d63",
"8fd5b8db10458ace7e4ed335eb0c66527e1928ad87a3c688595804f72b205e8c",
"a05400000843fbad6b28d2b76fc201c3d415a72d88d8dc548fafd8bae073c640"
]);
search in (AlertEvidence, DeviceEvents, DeviceFileEvents, DeviceImageLoadEvents, DeviceProcessEvents, DeviceNetworkEvents, SecurityEvent, ThreatIntelligenceIndicator)
TimeGenerated between ((selectedTimestamp - 1m) .. (selectedTimestamp + 90d))
and (SHA256 in (FileSHA256) or InitiatingProcessSHA256 in (FileSHA256))
Detect Microsoft Defender Antivirus detections related to Sapphire Sleet
The following query searches for Defender Antivirus alerts for the specific malware families used in this campaign and joins with device information for enriched context:
To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.
In mid-January 2026, Microsoft Defender Experts identified a credential theft campaign that uses fake virtual private network (VPN) clients distributed through search engine optimization (SEO) poisoning. The campaign redirects users searching for legitimate enterprise software to malicious ZIP files on attacker-controlled websites to deploy digitally signed trojans that masquerade as trusted VPN clients while harvesting VPN credentials. Microsoft Threat Intelligence attributes this activity to the cybercriminal threat actor Storm-2561.
Active since May 2025, Storm-2561 is known for distributing malware through SEO poisoning and impersonating popular software vendors. The techniques they used in this campaign highlight how threat actors continue to exploit trusted platforms and software branding to avoid user suspicion and steal sensitive information. By targeting users who are actively searching for enterprise VPN software, attackers take advantage of both user urgency and implicit trust in search engine rankings. The malicious ZIP files that contain fake installer files are hosted on GitHub repositories, which have since been taken down. Additionally, the trojans are digitally signed by a legitimate certificate that has since been revoked.
In this blog, we share our in-depth analysis of the tactics, techniques, and procedures (TTPs) and indicators of compromise in this Storm-2561 campaign, highlighting the social engineering techniques that the threat actor used to improve perceived legitimacy, avoid suspicion, and evade detection. We also share protection and mitigation recommendations, as well as Microsoft Defender detection and hunting guidance.
From search to stolen credentials: Storm-2561 attack chain
In this campaign, users searching for legitimate VPN software are redirected from search results to spoofed websites that closely mimic trusted VPN products but instead deploy malware designed to harvest credentials and VPN data. When users click to download the software, they are redirected to a malicious GitHub repository (no longer available) that hosts the fake VPN client for direct download.
The GitHub repo hosts a ZIP file containing a Microsoft Windows Installer (MSI) installer file that mimics a legitimate VPN software and side-loads malicious dynamic link library (DLL) files during installation. The fake VPN software enables credential collection and exfiltration while appearing like a benign VPN client application.
This campaign exhibits characteristics consistent with financially motivated cybercrime operations employed by Storm-2561. The malicious components are digitally signed by “Taiyuan Lihua Near Information Technology Co., Ltd.”
Figure 1. Storm-2561 campaign attack chain
Initial access and execution
The initial access vector relies on abusing SEO to push malicious websites to the top of search results for queries such as “Pulse VPN download” or “Pulse Secure client,” but Microsoft has observed spoofing of various VPN software brands and has observed the GitHub link at the following two domains: vpn-fortinet[.]com and ivanti-vpn[.]org.
Once the user lands on the malicious website and clicks to download the software, the malware is delivered through a ZIP download hosted at hxxps[:]//github[.]com/latestver/vpn/releases/download/vpn-client2/VPN-CLIENT.zip. At the time of this report, this repository is no longer active.
Figure 2. Screenshot from actor-controlled website vpn-fortinet[.]com masquerading as FortinetFigure 3. Code snippet from vpn-fortinet[.]com showing download of VPN-CLIENT.zip hosted on GitHub
When the user launches the malicious MSI masquerading as a legitimate Pulse Secure VPN installer embedded within the downloaded ZIP file, the MSI file installs Pulse.exe along with malicious DLL files to a directory structure that closely resembles a real Pulse Secure installation path: %CommonFiles%\Pulse Secure. This installation path blends in with legitimate VPN software to appear trustworthy and avoid raising user suspicion.
Alongside the primary application, the installer drops malicious DLLs, dwmapi.dll and inspector.dll, into the Pulse Secure directory. The dwmapi.dll file is an in-memory loader that drops and launches an embedded shellcode payload that loads and launches the inspector.dll file, a variant of the infostealer Hyrax. The Hyrax infostealer extracts URI and VPN sign-in credentials before exfiltrating them to attacker-controlled command-and-control (C2) infrastructure.
Code signing abuse
The MSI file and the malicious DLLs are signed with a valid digital certificate, which is now revoked, from Taiyuan Lihua Near Information Technology Co., Ltd. This abuse of code signing serves multiple purposes:
Bypasses default Windows security warnings for unsigned code
Might bypass application whitelisting policies that trust signed binaries
Reduces security tool alerts focused on unsigned malware
Provides false legitimacy to the installation process
Microsoft identified several other files signed with the same certificates. These files also masqueraded as VPN software. These IOCs are included in the below.
Credential theft
The fake VPN client presents a graphical user interface that closely mimics the legitimate VPN client, prompting the user to enter their credentials. Rather than establishing a VPN connection, the application captures the credentials entered and exfiltrates them to attacker-controlled C2 infrastructure (194.76.226[.]93:8080). This approach relies on visual deception and immediate user interaction, allowing attackers to harvest credentials as soon as the target attempts to sign in. The credential theft operation follows the below structured sequence:
UI presentation: A fake VPN sign-in dialog is displayed to the user, closely resembling the legitimate Pulse Secure client.
Error display: After credentials are submitted, a fake error message is shown to the user.
Redirection: The user is instructed to download and install the legitimate Pulse Secure VPN client.
Access to stored VPN data: The inspector.dll component accesses stored VPN configuration data from C:\ProgramData\Pulse Secure\ConnectionStore\connectionstore.dat.
Data exfiltration: Stolen credentials and VPN configuration data are transmitted to attacker-controlled infrastructure.
Persistence
To maintain access, the MSI malware establishes persistence during installation through the Windows RunOnce registry key, adding the Pulse.exe malware to run when the device reboots.
Defense evasion
One of the most sophisticated aspects of this campaign is the post-credential theft redirection strategy. After successfully capturing user credentials, the malicious application conducts the following actions:
Displays a convincing error message indicating installation failure
Provides instructions to download the legitimate Pulse VPN client from official sources
In certain instances, opens the user’s browser to the legitimate VPN website
If users successfully install and use legitimate VPN software afterward, and the VPN connection works as expected, there are no indications of compromise to the end user. Users are likely to attribute the initial installation failure to technical issues, not malware.
Defending against credential theft campaigns
Microsoft recommends the following mitigations to reduce the impact of this threat.
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 huge majority of new and unknown variants.
Run endpoint detection and response (EDR) in block mode so that Microsoft Defender for Endpoint can block malicious artifacts, even when your non-Microsoft antivirus does not detect the threat or when Microsoft Defender Antivirus is running in passive mode. EDR in block mode works behind the scenes to remediate malicious artifacts that are detected post-breach.
Turn on web protection in Microsoft Defender for Endpoint.
Encourage users to use Microsoft Edge and other web browsers that support SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that contain exploits and host malware.
Enforce multifactor authentication (MFA) on all accounts, remove users excluded from MFA, and strictly require MFA from all devices, in all locations, at all times.
Remind employees that enterprise or workplace credentials should not be stored in browsers or password vaults secured with personal credentials. Organizations can turn off password syncing in browser on managed devices using Group Policy.
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 (set to block mode) – An active ‘Malagent’ malware was blocked – An active ‘Hyrax’ credential theft malware was blocked – Microsoft Defender for Endpoint VPN launched from unusual location
Defense evasion
The fake VPN software side-loads malicious DLL files during installation.
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.
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.
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 customers can run the following advanced hunting queries to find related activity in their networks:
Files signed by Taiyuan Lihua Near Information Technology Co., Ltd.
Look for files signed with Taiyuan Lihua Near Information Technology Co., Ltd. signer.
let a = DeviceFileCertificateInfo
| where Signer == "Taiyuan Lihua Near Information Technology Co., Ltd."
| distinct SHA1;
DeviceProcessEvents
| where SHA1 in(a)
Identify suspicious DLLs in Pulse Secure folder
Identify launching of malicious DLL files in folders masquerading as Pulse Secure.
DeviceImageLoadEvents
| where FolderPath contains "Pulse Secure" and FolderPath contains "Program Files" and (FolderPath contains "\\JUNS\\" or FolderPath contains "\\JAMUI\\")
| where FileName has_any("inspector.dll","dwmapi.dll")
To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.