A newly discovered Linux malware, which has evaded detection for over a year, allows attackers to gain persistent SSH access and bypass authentication on compromised systems.

Nextron Systems security researchers, who identified the malware and dubbed it “Plague,” describe it as a malicious Pluggable Authentication Module (PAM) that uses layered obfuscation techniques and environment tampering to avoid detection by traditional security tools.

This malware features anti-debugging capabilities to thwart analysis and reverse engineering attempts, string obfuscation to make detection more difficult, hardcoded passwords for covert access, as well as the ability to hide session artifacts that would normally reveal the attacker’s activity on infected devices.