An ongoing, widespread malware campaign has been observed to install fake Google Chrome and Microsoft Edge extensions via a trojan distributed via fake websites posing as popular software.
“Malware Trojans contain a variety of results, ranging from simple adware extensions that hijack search engines to more sophisticated malicious scripts that deliver local extensions to steal private data and execute various commands,” ReasonLabs research team. said in the analysis.
“This malicious Trojan, which has been around since 2021, comes from impersonating download websites with add-ons for online games and videos.”
At least 300,000 Google Chrome and Microsoft Edge users are affected by the malware and extensions, indicating the widespread impact of this activity.
The campaign is based on using malicious ads to push similar websites that advertise popular software, such as Roblox FPS Unlocker, YouTube, VLC media player, Steam or KeePass, to force users looking for these programs to download a trojan that acts as a conduit for installing browser extensions.
Digitally signed malicious installers register a scheduled task, which in turn is configured to execute a PowerShell script that is responsible for downloading and executing the next-stage payload received from the remote server.
This includes modifying the Windows registry to force the installation of extensions from the Chrome Web Store and Microsoft Edge add-ons that are capable of intercepting Google and Microsoft Bing search queries and redirecting them through servers controlled by the attacker.
“The extension cannot be disabled by the user even if developer mode is ON,” ReasonLabs said. “New versions of the script remove browser updates.”
It also runs a local extension that is downloaded directly from the Command and Control (C2) server and has extensive capabilities to intercept all web requests and send them to the server, retrieve commands and encrypted scripts, and inject and load scripts to all pages.
In addition, it captures search queries from Ask.com, Bing and Google and routes them through its servers and then to other search engines.
This is not the first time that such campaigns have been observed in the wild. In December 2023, a cyber security campaign in detail another Trojan installer that comes via torrents and installs malicious web extensions that masquerade as VPN applications but are actually designed to run the “cashback hack”.
