CVE-2004-2396 in PassWD
Summary
by MITRE
passwd 0.68 does not check the return code for the pam_start function which has unknown impact and attack vectors that may prevent "safe and proper operation" of pam.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability identified as CVE-2004-2396 affects the passwd utility version 0.68 and represents a critical flaw in the Pluggable Authentication Modules PAM framework implementation. This issue stems from the passwd utility's failure to properly validate the return code from the pam_start function call, creating a potential security risk that could compromise the integrity of the authentication process. The vulnerability exists within the authentication handling mechanism of the passwd program, which is responsible for managing user password changes and authentication contexts.
The technical flaw manifests when the passwd utility invokes pam_start to initialize the PAM authentication context but fails to examine the return value for error conditions. This oversight means that if pam_start encounters issues such as module loading failures, configuration errors, or other initialization problems, the passwd utility continues execution without proper authentication context. The lack of proper error handling creates a scenario where authentication may proceed in an insecure state, potentially allowing unauthorized access or bypassing authentication controls entirely. This behavior directly violates security best practices for authentication system implementation and represents a failure in defensive programming principles.
The operational impact of this vulnerability extends beyond simple authentication failures, potentially enabling various attack vectors that could compromise system security. An attacker could exploit this weakness to bypass authentication mechanisms, especially when the pam_start function fails due to missing or misconfigured PAM modules. The vulnerability's unknown impact and attack vectors suggest that the consequences could be severe, potentially allowing privilege escalation, unauthorized system access, or complete bypass of the authentication framework. This flaw undermines the fundamental security guarantees that PAM is designed to provide, creating potential pathways for malicious actors to gain unauthorized access to systems.
From a cybersecurity perspective, this vulnerability aligns with CWE-254, which addresses security weaknesses related to improper error handling in authentication systems, and represents a classic example of insufficient error handling that could be exploited by attackers following ATT&CK technique T1548.003 for bypassing system protections. The vulnerability demonstrates how seemingly minor programming errors in authentication components can have significant security implications, particularly in systems where authentication is a core security control. Organizations using affected versions of passwd should consider immediate remediation through patching or updating to versions that properly validate PAM function return codes.
Mitigation strategies should focus on ensuring proper error handling in authentication components and implementing comprehensive testing procedures for PAM integration. System administrators should verify that all PAM functions are properly validated and that appropriate error handling mechanisms are in place to detect and respond to authentication initialization failures. The fix involves modifying the passwd utility code to check the return value of pam_start and implement appropriate error recovery procedures, ensuring that authentication failures are properly handled and that the system maintains secure operational states even when PAM initialization encounters problems. Regular security auditing of authentication components and adherence to security standards such as those defined in NIST SP 800-53 and ISO 27001 is essential for preventing similar vulnerabilities in authentication systems.