Threats Tagged 'base64 obfuscation'

A sophisticated phishing campaign targets Windows users with fraudulent Bank of America emails, delivering ScreenConnect remote monitoring software as malware. The attack begins with convincing emails mimicking Bank of America branding, directing victims to fake security pages. Windows users receive AccountGuard.zip containing a VBS file with multiple layers of base64-encoded content. The attack chain deploys complex decoding scripts and employs a UAC bypass exploit via ICMLuaUtil COM interface to install ScreenConnect with administrator privileges. Additional components use SDDL and ACLs to hide the installation, prevent uninstallation, and conceal the malicious service. The installed client connects to command-and-control infrastructure in the UAE. Mac users encounter traditional credential phishing pages requesting banking credentials and personal information instead of receiving malware payloads.

The ClickFix campaign has evolved from basic disk-based infections to sophisticated, obfuscated attacks using fake CAPTCHA pages that trick victims into executing malicious PowerShell commands. Initial variants used cleartext commands downloading batch scripts to deploy DeerStealer InfoStealer. The campaign advanced to fileless execution using XOR encryption or Base64 compression, operating entirely in memory. The most dangerous evolution involves server-side polymorphism, where attacker infrastructure dynamically generates unique obfuscated payloads for each victim, delivering Vidar InfoStealer. Active since March 2026 with surging activity through May, the campaign utilizes approximately 4,500 live domains. Both XOR and Base64 variants execute payloads in memory, download executables from attacker infrastructure, and delete traces to evade forensics.