CVE-2002-0757 in Webmin
Summary
by MITRE
(1) Webmin 0.96 and (2) Usermin 0.90 with password timeouts enabled allow local and possibly remote attackers to bypass authentication and gain privileges via certain control characters in the authentication information, which can force Webmin or Usermin to accept arbitrary username/session ID combinations.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability described in CVE-2002-0757 represents a critical authentication bypass flaw affecting Webmin 0.96 and Usermin 0.90 when password timeout functionality is enabled. This issue stems from improper input validation of authentication credentials, specifically targeting how the software processes control characters within authentication information. The vulnerability creates a pathway for both local and remote attackers to circumvent the normal authentication mechanisms by exploiting weaknesses in the session management and credential verification processes.
The technical implementation of this flaw involves the manipulation of control characters within authentication data, which allows attackers to force the Webmin or Usermin applications to accept arbitrary username and session ID combinations. This occurs because the software fails to properly sanitize or validate input containing control characters during the authentication process, leading to unexpected behavior in session handling routines. The vulnerability specifically targets the password timeout feature, suggesting that the issue is more pronounced when authentication sessions are being managed or renewed within the application's security framework.
From an operational impact perspective, this vulnerability enables attackers to gain unauthorized access to administrative functions within Webmin and Usermin environments, potentially leading to complete system compromise. The ability to bypass authentication with arbitrary combinations means that an attacker could access sensitive system configurations, user accounts, and administrative controls without proper credentials. This creates a severe risk for systems where these applications are deployed, particularly in environments where they serve as web-based management interfaces for critical infrastructure components.
The vulnerability aligns with CWE-20, which addresses improper input validation, and demonstrates characteristics consistent with authentication bypass techniques documented in various ATT&CK frameworks under credential access and privilege escalation categories. Organizations should implement immediate mitigations including disabling password timeout features if not required, applying available patches from the software vendors, and monitoring for suspicious authentication attempts. Network segmentation and access controls should be strengthened to limit exposure, while regular security audits should verify that authentication mechanisms are properly configured and functioning as intended. The vulnerability underscores the importance of proper input sanitization and the need for robust session management in web-based administrative interfaces.