VERY IMPORTANT

A sophisticated backdoor disguised as a legitimate Malwarebytes installer was distributed to over 100,000 machines through compromised automatic updates of one torrent client (Download Studio) and three adblockers (NetShield Kit, My AdBlock, and Net AdBlock). The backdoor creates a fake Malwarebytes installation directory containing legitimate signed files alongside malicious DLL files. Once executed, it establishes persistence through a Windows service and communicates with command-and-control servers to receive configuration updates and additional payloads. The primary observed payloads were cryptocurrency miners, though the infrastructure supports delivery of multiple persistent threats. The attack demonstrates abuse of software update mechanisms and affects primarily users in Russia, Ukraine, and Kazakhstan.