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UpdateAgent is a trojan targeting macOS, first discovered in 2020. UpdateAgent is a macOS trojan that has evolved significantly since its discovery, gaining the ability to bypass macOS Gatekeeper protections. It masquerades as legitimate software such as video apps or support agents and tricks users into installing it. Once active, UpdateAgent can deploy additional malware payloads including adware like Adload, harvest system information, and modify the LaunchAgent folder for persistence. Microsoft's threat intelligence team tracked its evolution across multiple versions, each adding more sophisticated evasion techniques including the ability to abuse legitimate cloud services for payload hosting. CoreLock detects this threat using CoreLock detects UpdateAgent by monitoring for Gatekeeper bypass techniques, flagging preinstall and postinstall scripts in .pkg installers that execute suspicious commands, identifying outbound connections to cloud storage services used for secondary payload delivery, and applying YARA rules matching known UpdateAgent binary patterns across its multiple evolution stages.

DangerTrojanDiscovered 2020

UpdateAgent

Also known as: OSX.UpdateAgent, WizardUpdate, Silver Toucan

What is UpdateAgent?

UpdateAgent is a macOS trojan that has evolved significantly since its discovery, gaining the ability to bypass macOS Gatekeeper protections. It masquerades as legitimate software such as video apps or support agents and tricks users into installing it. Once active, UpdateAgent can deploy additional malware payloads including adware like Adload, harvest system information, and modify the LaunchAgent folder for persistence. Microsoft's threat intelligence team tracked its evolution across multiple versions, each adding more sophisticated evasion techniques including the ability to abuse legitimate cloud services for payload hosting.

How It Spreads

Drive-by downloads from malicious or compromised websites disguised as legitimate application updates

Fake software installers for video tools, productivity apps, and tech support utilities

Malvertising campaigns on popular websites that redirect to trojanized download pages

Bundled with legitimate-looking .pkg installers that use preinstall and postinstall scripts to deploy the trojan

Signs of Infection

Unexpected adware or browser hijacking appearing after installing a new application

New LaunchAgent plist files in ~/Library/LaunchAgents/ with random or unfamiliar names

Outbound network connections to Amazon S3, CloudFront, or other cloud storage services downloading unknown payloads

System Preferences showing new configuration profiles you did not install

How to Remove UpdateAgent

1

Remove suspicious applications

Check /Applications/ and ~/Downloads/ for recently installed unfamiliar applications. Delete any apps you don't recognize or that you installed just before symptoms appeared.

2

Remove LaunchAgent persistence

In Terminal, list LaunchAgents: ls -la ~/Library/LaunchAgents/ and ls -la /Library/LaunchAgents/. Delete any plist files with random names or that reference unfamiliar executables. Check the ProgramArguments key in suspicious plists with: plutil -p <filename>.plist

3

Remove configuration profiles

Go to System Settings > Privacy & Security > Profiles (or System Preferences > Profiles on older macOS). Remove any profiles you did not install. UpdateAgent can install profiles to enforce browser or proxy settings.

4

Remove secondary payloads (Adload)

UpdateAgent frequently deploys Adload as a secondary payload. Check for Adload persistence: look for files in /Library/Application Support/ with random folder names and browser extensions you did not install.

5

Clear browser data and extensions

Remove unfamiliar browser extensions from Safari (Settings > Extensions), Chrome (chrome://extensions), and Firefox (about:addons). Reset homepage and search engine if they were changed.

6

Scan with CoreLock

Run a full CoreLock scan to detect UpdateAgent components, any secondary payloads it deployed, and residual persistence mechanisms that manual cleanup may have missed.

Prevention Tips

Only download software from the Mac App Store or verified developer websites

Be skeptical of applications that require you to right-click and Open to bypass Gatekeeper warnings

Keep macOS updated — Apple continuously improves Gatekeeper and XProtect to detect UpdateAgent variants

Use CoreLock to monitor for Gatekeeper bypass attempts and unauthorized payload downloads from cloud services

How CoreLock Detects UpdateAgent

Real-time Detection

CoreLock detects UpdateAgent by monitoring for Gatekeeper bypass techniques, flagging preinstall and postinstall scripts in .pkg installers that execute suspicious commands, identifying outbound connections to cloud storage services used for secondary payload delivery, and applying YARA rules matching known UpdateAgent binary patterns across its multiple evolution stages.

Frequently Asked Questions

How does UpdateAgent bypass macOS Gatekeeper?

UpdateAgent evolved to bypass Gatekeeper by removing the quarantine attribute from downloaded files using the xattr -d com.apple.quarantine command in its installer scripts. This prevents macOS from showing the standard security warning when users open downloaded applications. Some variants also exploit .pkg installer scripts that execute with elevated privileges before Gatekeeper checks are applied.

How do I know if my Mac has UpdateAgent?

Signs include unexpected adware appearing on your Mac, unfamiliar browser extensions, new configuration profiles in System Settings, and unknown LaunchAgent files. If you recently installed an app and then started seeing ads, pop-ups, or browser hijacking, UpdateAgent may have installed adware like Adload as a secondary payload. Check Activity Monitor for unfamiliar processes and run a CoreLock scan.

What payloads does UpdateAgent install?

UpdateAgent primarily deploys adware payloads, with Adload being the most common secondary payload. It downloads these payloads from legitimate cloud services like Amazon S3 and CloudFront, making network-based detection harder. Some variants have also deployed browser hijackers and data collection tools. The modular design means new payloads can be swapped in by the operators.

Is UpdateAgent related to legitimate macOS software updates?

No. UpdateAgent has no connection to Apple's legitimate macOS Software Update mechanism. The name refers to the malware's strategy of disguising itself as an update utility. Legitimate macOS updates only come through System Settings > Software Update or the Mac App Store. Any application claiming to be a system update downloaded from a website is suspicious.

Protect Your Mac from UpdateAgent

Download CoreLock to detect and remove UpdateAgent and other macOS threats. AI-powered analysis, real-time monitoring, and one-click remediation.

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Available for macOS and Windows