Description

A new malware campaign dubbed SORVEPOTEL is rapidly spreading through WhatsApp messages, primarily targeting Windows systems in Brazil. Instead of focusing on data theft or ransomware, this malware prioritizes self-propagation using social engineering and automation. Victims receive phishing messages in Portuguese from compromised contacts, urging them to open ZIP attachments disguised as legitimate documents. Once opened, these archives contain malicious .LNK shortcut files that launch PowerShell or CMD scripts to fetch the main payload from attacker-controlled domains. The malware payload—a batch script—establishes persistence by copying itself to the Windows Startup folder, ensuring it runs at every reboot. It executes an obfuscated PowerShell command in hidden mode, contacting various C&C servers to retrieve further in-memory payloads. These techniques reduce traces on disk, helping evade traditional detection methods. Trend Micro found no evidence of data exfiltration or encryption, suggesting the malware's current purpose is rapid spread rather than long-term system compromise. SORVEPOTEL also detects active WhatsApp Web sessions on infected machines and uses them to automatically forward the same ZIP file to all contacts and groups, accelerating its propagation. This behavior often leads to account suspensions for violating WhatsApp’s policies. The campaign also uses typo-squatted domains mimicking benign phrases to avoid suspicion and expand its reach. To defend against such threats, organizations should disable automatic execution of LNK files, monitor for unusual WhatsApp Web activity, and enforce strong phishing controls. User training, endpoint security updates, and applying least-privilege principles are essential to reduce exposure and prevent future escalation.