Source: cve@mitre.org
AIX passwd allows local users to gain root access.
AIX passwd, a critical vulnerability dating back to 1992, allows local users to escalate privileges to root. This flaw, if present in vulnerable systems, can lead to complete system compromise and data exfiltration, posing a significant risk to confidentiality, integrity, and availability.
Step 1: Local Access: An attacker gains local access to the AIX system, potentially through a compromised user account or physical access.
Step 2: Vulnerability Trigger: The attacker executes the passwd utility, likely attempting to change their password or exploit a specific input sequence.
Step 3: Exploitation: The attacker crafts a malicious input, potentially triggering a buffer overflow or other vulnerability within the passwd utility.
Step 4: Privilege Escalation: The crafted input overwrites critical memory locations or executes malicious code, gaining root privileges.
Step 5: System Compromise: With root access, the attacker can modify system files, install backdoors, and gain complete control of the system.
The vulnerability lies within the passwd utility on AIX systems. The root cause is a privilege escalation flaw. While the exact mechanism isn't fully detailed in the provided information, it's highly probable that the passwd utility, when handling user password changes, fails to properly validate input or handle internal state transitions securely. This could manifest as a buffer overflow, format string vulnerability, or a race condition during the authentication or password update process. The lack of proper input validation or secure handling of temporary files or processes could allow a local user to overwrite critical system files or execute arbitrary code with root privileges.
Due to the age of this vulnerability, it's likely targeted by a wide range of actors, from script kiddies to sophisticated threat actors. It's highly probable that this vulnerability is used by APTs targeting legacy systems. This vulnerability is not listed in CISA KEV as of the current date.
Monitor system logs for unusual activity related to the passwd utility, including failed login attempts or unexpected errors.
Analyze process execution logs for suspicious processes spawned by the passwd utility.
Examine file system integrity, looking for unauthorized modifications to system files.
Implement file integrity monitoring (FIM) to detect changes to critical system binaries, including passwd.
Network monitoring for unusual traffic patterns originating from the compromised host.
Apply security patches provided by IBM for the affected AIX versions. This is the primary and most effective remediation step.
If patching is not immediately feasible, restrict access to the passwd utility to only authorized users.
Implement strong password policies and enforce regular password changes.
Monitor system logs and audit user activity to detect any suspicious behavior.
Implement a robust intrusion detection and prevention system (IDPS) to identify and block malicious activity.
Consider upgrading to a supported version of AIX.