CVE-2006-6683 in chetcpasswd
Summary
by MITRE
Pedro Lineu Orso chetcpasswd 2.4.1 and earlier verifies and updates user accounts via custom code that processes /etc/shadow and does not follow the PAM configuration, which might allow remote attackers to bypass intended restrictions implemented through PAM.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/12/2018
The vulnerability identified as CVE-2006-6683 affects Pedro Lineu Orso chetcpasswd version 2.4.1 and earlier, representing a critical security flaw in password management functionality. This issue stems from the software's custom implementation for processing user account verification and updates, which directly manipulates the /etc/shadow file without adhering to the established PAM (Pluggable Authentication Modules) configuration. The fundamental problem lies in the bypass of system-level authentication controls that are typically enforced through PAM, creating a significant security gap that can be exploited by remote attackers.
The technical flaw manifests in the application's failure to integrate with the standard authentication framework that governs user account modifications on Unix-like systems. When chetcpasswd processes password updates, it operates outside the PAM chain, meaning it does not validate against the configured authentication policies, account restrictions, or password quality requirements that would normally be enforced. This custom code approach directly accesses and modifies the /etc/shadow file, which contains critical password and account information, effectively circumventing all the security controls that PAM would normally enforce during authentication and account management operations.
The operational impact of this vulnerability is severe as it allows remote attackers to bypass intended restrictions that are typically implemented through PAM configurations. Attackers can exploit this flaw to modify user accounts without proper authentication, potentially gaining unauthorized access to systems or escalating privileges beyond what should be permitted. The vulnerability undermines the principle of least privilege and can result in complete compromise of user account management functionality, as the application's custom code does not enforce the same security checks that would normally be applied through the standard PAM authentication flow.
This vulnerability aligns with CWE-692, which describes inadequate enforcement of input validation, and represents a failure in proper authentication mechanism integration. From an ATT&CK perspective, this issue maps to T1078 Valid Accounts and T1566 Phishing, as it can enable attackers to establish persistent access through compromised accounts or exploit the bypass to gain unauthorized system access. The security implications extend beyond simple password changes, potentially allowing attackers to create accounts, modify existing user permissions, or disable account restrictions that would normally prevent unauthorized modifications. Organizations using affected versions of chetcpasswd should immediately implement mitigations including updating to patched versions, implementing network segmentation, and monitoring for unauthorized account modifications to prevent exploitation of this critical vulnerability.