MAL-2026-11494 Malicious code in test-dev-sync (npm)

test-dev-sync is a browser data stealer coupled to a remote-command backdoor. grabber_user.js enumerates Chrome/Chromium/Opera/Vivaldi profiles under LOCALAPPDATA and copies extension Local/Sync settings, Local Storage LevelDB, and the LastPass extension database; the collected tree is zipped and uploaded, keyed by a hardware fingerprint, through a sibling package's uploadFileToPublicApi sink. extproc.js additionally reads each profile's Secure Preferences JSON, derives a seed hash from resources.pak, collects the host SID via powershell, and uploads the resulting extinfo blob to the same sink. handleInstallExtension listens on a channel provided by the sibling test-dev-link, receives operator messages carrying an extension ZIP, unzips it into the Chrome User Data Extensions directory, terminates chrome.exe, rewrites Secure Preferences to authorize the planted extensions, adds HKCU\Software\Policies\Google\Chrome entries that disable developer-mode and extension restrictions, and relaunches Chrome with –restore-last-session, giving persistent operator control of the victim's browser. The package is presented under a generic "dev sync" name and splits its capabilities across sibling packages test-dev-config, test-dev-link, and test-dev-store, which supply the C2 channel, hardware fingerprint, and upload endpoint.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.