Shadow Vector: Brazilian APT's Memory-Resident Banking Malware Evades Detection

A new advanced persistent threat (APT) group operating out of Brazil has been identified deploying a sophisticated memory-resident banking malware with concerning evasion capabilities. Dubbed 'Shadow Vector' by security researchers, this campaign represents a significant evolution in Latin American cybercrime tactics.

The malware's most distinctive feature is its exclusive operation in system memory, never writing to disk. This RAM-only persistence mechanism allows it to bypass traditional file-based antivirus solutions. The attackers achieve this through a multi-stage loading process that begins with a small dropper delivered via phishing emails containing malicious Office documents or PDFs.

Once executed, the dropper uses process hollowing techniques to inject malicious code into legitimate processes such as explorer.exe or svchost.exe. The malware then establishes TLS-encrypted command and control (C2) channels to download additional payloads directly into memory. These payloads include banking trojan modules specifically designed to target over 15 major Latin American financial institutions.

The financial theft capabilities are particularly sophisticated. The malware can:

• Inject fake login forms into legitimate banking websites
• Modify transaction details in real-time
• Bypass two-factor authentication through session hijacking
• Capture keystrokes and take screenshots

What makes Shadow Vector particularly concerning is its adaptive infrastructure. The C2 servers rotate IP addresses frequently and use domain generation algorithms (DGAs) to maintain persistence while evading takedowns. Researchers have also observed the malware checking for virtual machine environments and security tools before activating its malicious payloads.

Defense against such threats requires a shift from traditional signature-based detection. Security teams should:

1. Implement memory scanning solutions
2. Deploy behavior-based detection systems
3. Monitor for process hollowing techniques
4. Restrict Office macro execution
5. Enforce application whitelisting

The emergence of Shadow Vector signals a troubling trend in Latin American cybercrime, where threat actors are adopting APT-style tactics traditionally associated with nation-state groups. Financial institutions and their customers should remain vigilant against sophisticated phishing attempts and consider additional transaction verification measures.