7 Critical Linux PAM Backdoor Flaws Revealed
Hardening the Gatekeeper: Defending Against Linux PAM Backdoor Attacks Executive Summary (TL;DR) The Threat: The Linux PAM backdoor (exemplified by PamDOORa) exploits the legitimate authentication framework to intercept credentials (passwords, tokens) during the login process. The Mechanism: Attackers modify system-critical files (like /etc/pam.d/ ) to inject malicious modules that run before standard authentication checks, giving them a privileged window into unencrypted data streams. Immediate Action: Audit all files within /etc/pam.d/ and restrict write access using strict filesystem controls (e.g., immutable attribute). Architectural Fix: Never rely solely on local PAM configuration. Implement MFA , use key-based authentication only , and enforce SELinux/AppArmor policies that explicitly deny modification to PAM modules. Core Principle: Assume the authentication stack is compromised and build defenses around the data , not just the process . We build highly resi...