sideloading

LastPass has identified a sophisticated scheme targeting users of its Authenticator app, involving SEO poisoning and deceptive GitHub pages that distribute malicious ZIP files disguised as legitimate software. Users searching for "LastPass Authenticator download" may encounter these counterfeit pages, which redirect them to a malicious server delivering a ZIP file containing vsdbg.exe and vsdbg.dll. The executable is a legitimate Microsoft debugging tool exploited to execute the malicious DLL through DLL sideloading, allowing the malware to run undetected. Named Rapuncel by security researchers from Delphos, this malware is undetectable by antivirus engines and targets a hardcoded list of 145 antivirus and endpoint security products, disabling them upon detection. Rapuncel harvests sensitive information, including saved passwords from over 25 web browsers, cryptocurrency wallet files from more than 30 applications, and session tokens from platforms like Discord and Steam. It also captures screenshots and compiles a profile of the infected system, uploading the stolen data to an attacker-controlled server. The malware includes a kernel driver that intercepts web traffic, allowing for advertisement injection and search result manipulation. This campaign has been active for several months, with LastPass vaults remaining unaffected. Users are advised to download applications only from trusted sources. Rapuncel establishes persistence on infected machines by installing itself as a Windows service that starts with the system and terminates activated security products. Removing the kernel driver requires booting into Safe Mode or using external recovery tools, as standard Windows utilities cannot eliminate software operating at that level.