Plague in the Shadows: Unmasking a Silent Linux Backdoor

The Plague backdoor is a stealthy and well-crafted Linux malware that has silently infiltrated systems by hooking into PAM (Pluggable Authentication Modules), allowing attackers to bypass authentication and maintain persistent SSH access, all while going undetected by antivirus engines. The malware has evolved over time, with threat actors actively developing new variants using increasingly complex string obfuscation and encryption techniques to avoid analysis. Plague also includes anti-debugging features, static credentials, and environment tampering to erase traces of attacker activity from system logs and session histories. Plague remains a quiet yet serious threat to Linux infrastructure, emphasizing the need for proactive behavioral detection, careful PAM auditing, and a greater focus on securing authentication components.