AuthDoor
AuthDoor is a PAM backdoor for Linux systems that was observed in 2024 intrusions targeting telecommunications providers in Southeast/Southwest Asia. It was deployed by overwriting the legitimate pam_unix.so or pam_unix2.so module on certain hosts and hooking PAM authentication functionality, including pam_sm_authenticate, to capture user credentials. Captured credentials were stored in a hidden log file, specifically /usr/bin/.dbus.log, with credentials encoded in ASCII hex. AuthDoor also supports persistent access through a hard-coded magic password, allowing access even if legitimate user passwords are changed, and it can execute files from a specific directory for persistence. The malware was associated with the nation-state-linked cluster CL-STA-0969, which Unit 42 assessed as heavily overlapping with the China-linked Liminal Panda activity set. The broader campaign targeted critical telecommunications infrastructure and used SSH brute-force for likely initial access, followed by Linux privilege-escalation exploits and multiple custom implants for covert persistence and access.
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Groups observed using it
1 distinct threat actor attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
AuthDoor: A PAM backdoor that captures user credentials by hooking into authentication functions. It supports hardcoded password access, updates stolen credentials in a hidden log, and can execute files from a specific directory for persistent access.
IOCs tracked for this family
2 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
File hashes (MD5, SHA-1, SHA-256) from samples and reports.
Recent activity
2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A PAM backdoor that captures credentials, supports hardcoded password access, logs stolen credentials, and enables persistent access by executing files from a specific directory.
Linux PAM backdoor that replaces pam_unix* to capture credentials (stored as ASCII hex in /usr/bin/.dbus.log), provides access via a hard-coded “magic password” for persistence even after password changes, and can enumerate/execute files in /var/spool/.network/.
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Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.