CVE-2005-3503 in pwdutils
Summary
by MITRE
chfn in pwdutils 3.0.4 and earlier on suse linux and possibly other operating systems does not properly check arguments for the gecos field which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2005-3503 affects the chfn command utility within pwdutils version 3.0.4 and earlier installations on SUSE Linux and potentially other operating systems. This flaw resides in the gecos field argument validation mechanism, which is a critical component of user account management in Unix-like systems where the gecos field typically stores additional user information such as full name, office location, and phone numbers. The chfn command serves as the primary interface for modifying these user details, making it a fundamental administrative tool that requires robust security controls.
The technical flaw stems from insufficient input validation within the chfn utility's argument parsing logic specifically for the gecos field parameter. When users execute chfn with malformed or specially crafted arguments, the utility fails to properly sanitize or validate the input before processing it. This inadequate validation creates a potential privilege escalation vector where local attackers can manipulate the gecos field in ways that trigger unexpected behavior within the system's user management subsystem. The vulnerability represents a classic case of improper input validation that can lead to unauthorized privilege elevation.
From an operational impact perspective, this vulnerability allows local users to potentially escalate their privileges from standard user level to root access. The attack typically involves exploiting the flawed argument handling to manipulate system calls or file operations that should only be accessible to privileged processes. The implications extend beyond simple privilege escalation as this vulnerability could enable attackers to modify critical system user accounts, potentially leading to persistent access or further compromise of the system. The vulnerability affects systems where pwdutils is installed, which is standard across most Unix and Linux distributions, making it widely exploitable.
Security professionals should implement immediate mitigations including updating to pwdutils version 3.0.5 or later where the input validation has been corrected. Organizations should also conduct thorough audits of their user account management systems to identify any potential exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation, and falls under ATT&CK technique T1068, privilege escalation through local exploits. Additional defensive measures include implementing strict access controls on user management utilities, monitoring for unusual chfn command executions, and ensuring proper system hardening practices. System administrators should also consider implementing automated patch management solutions to prevent similar vulnerabilities from persisting across their infrastructure.