A Mac malware warning has been issued for any individual who recently downloaded Handbrake for Mac. A server was compromised and a remote access Trojan was bundled with the Handbrake Apple Disk Image file.

A credential-stealing Remote Access Trojan was discovered to have been bundled with the Handbrake video transcoder app for the MacOS, with Handbrake for Mac downloads between May 2 and May 6, 2017 potentially also installing the MacOS Proton RAT.

A Mac malware warning has been issued for all users who recently downloaded the app. It is strongly recommended that any individual who downloaded the app between the above dates verifies that they have not been infected. According to a statement issued by the developers of the app, individuals have a 50/50 change of infection if they downloaded the app between the above dates.

Cybercriminals were able to compromise a server and bundle the malware with the app, with all users who used the download.handbrake.fr mirror potentially infected.

Apple has now updated its OSX’s XProtect to detect and remove the infection although individuals at risk should check to see if their device has been infected. Infection can be detected by looking for the Activity_agent process in the OSX Activity Monitor. If the process is running, the device has been infected with the Trojan.

Any user infected with the malware will need to change all passwords stored in the MacOS keychain. Any password stored in a browser will also need to be changed, as it is probable it has also been compromised.

The Trojan can be easily removed by opening the Terminal and entering the following commands before removing all instances of the Handbrake app:

  • launchctl unload ~/Library/LaunchAgents/fr.handbrake.activity_agent.plist
  • rm -rf ~/Library/RenderFiles/activity_agent.app
  • if ~/Library/VideoFrameworks/ contains proton.zip, remove the folder

The MacOS Proton RAT was first identified earlier this year. It is capable of logging keystrokes to steal passwords, can execute shell commands as root, steal files, take screenshots of the desktop and access the webcam. Once installed, it will run every time the user logs on.

Only Handbrake for Mac downloads were affected. Any user who recently upgraded through the Handbrake update mechanism will not be affected, as checks are performed to prevent the downloading of malicious files.

The compromised server has now been shut down to prevent any further malware downloads. At this stage it is unclear how access to the server was gained and how the Handbrake Apple Disk Image file was replaced with a malicious version.