WhatsApp-Based Worm Drives Astaroth Banking Trojan Surge Across Brazil
In late 2025 and early 2026, a major cybersecurity campaign—codenamed Boto Cor-de-Rosa—targeted millions of WhatsApp users in Brazil with the Astaroth (Guildma) banking trojan. Threat actors leveraged a novel worm module written in Python that hijacked victims’ WhatsApp contact lists, automatically sending malicious ZIP files and spreading the malware with unprecedented speed. Upon execution, the ZIP archive dropped a Visual Basic script that downloaded further payloads, including a banking module capable of harvesting credentials when victims accessed online banking sites. Over 95% of reported infections occurred in Brazil, severely impacting personal and financial data security. This campaign highlights how cybercriminals are weaponizing popular messaging apps as attack vectors for financial malware, reflecting the rising sophistication and modularity of their methods. The shift to WhatsApp-based propagation, combined with multi-language modular code, signals a concerning trend for businesses and individuals in regions with high platform adoption rates.
Kill Chain