A new phishing campaign, orchestrated by the Russian APT group Fighting Ursa, has emerged, utilizing a “car for sale” advertisement to spread the HeadLace backdoor malware. Since March 2024, this sophisticated attack has targeted Windows systems by leveraging the lure of a seemingly benign car sales ad. The campaign demonstrates the group’s ability to exploit legitimate online services for malicious purposes, illustrating a concerning trend in cyber threats.
The attack employed Webhook.site, a legitimate service for creating custom URLs, as a conduit for the malware. Initially, the attackers used the service to host a malicious HTML page that was presented to visitors accessing the compromised ad. For Windows users, the page offered a Base64-encoded ZIP file disguised as a JPG image. The ZIP file, however, contained a malicious executable designed to evade detection by masquerading as a harmless image.
Upon downloading and executing the ZIP archive, the file, named IMG-387470302099.jpg.exe, was disguised with a double extension to deceive users into believing it was a harmless image. This social engineering tactic successfully tricked many into running the malware. Once executed, the malware, disguised as a Windows calculator, sideloaded the WindowsCodecs.dll file, a crucial component of the HeadLace backdoor, which facilitated the installation of additional malicious code.
Fighting Ursa’s use of legitimate web services for distributing malware highlights the evolving nature of cyber threats. The multi-stage attack process, which involved embedding malicious code within a legitimate application, underscores the necessity for robust security measures. Organizations are advised to restrict access to such platforms and scrutinize their usage to prevent similar infections. This campaign serves as a reminder of the importance of vigilance and proactive defense strategies in combating sophisticated cyber threats.
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