CVE-2001-1074 in Webmin
Summary
by MITRE
Webmin 0.84 and earlier does not properly clear the HTTP_AUTHORIZATION environment variable when the web server is restarted, which makes authentication information available to all CGI programs and allows local users to gain privileges.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2001-1074 represents a critical authentication bypass flaw in Webmin versions 0.84 and earlier. This issue stems from improper handling of the HTTP_AUTHORIZATION environment variable during web server restart operations. The flaw allows local users to potentially escalate privileges by leveraging cached authentication information that should have been cleared upon server restart. The vulnerability exists at the system integration level where web server processes fail to properly sanitize environment variables, creating a persistent security risk across CGI applications.
The technical implementation of this vulnerability involves the web server's failure to clear the HTTP_AUTHORIZATION environment variable when processes are restarted or reinitialized. This variable typically contains base64-encoded authentication credentials that are used to verify user identity when accessing protected resources. When the web server restarts, the system should ensure that all authentication context is properly cleared from the environment variables. However, in affected versions of Webmin, this cleanup process fails, leaving authentication tokens accessible to subsequent CGI programs that execute within the same process context.
From an operational impact perspective, this vulnerability creates a significant risk for local users who may exploit the persistent authentication information to gain unauthorized access to administrative functions. The flaw essentially allows privilege escalation by enabling attackers to reuse authentication tokens that should have been invalidated during the server restart process. This type of vulnerability falls under CWE-200, which addresses improper information exposure, and represents a classic example of insufficient cleanup of sensitive data. The attack vector is particularly concerning because it requires only local access to exploit, making it accessible to users who already have system-level privileges.
The security implications extend beyond simple credential reuse, as this vulnerability can be leveraged to perform administrative actions without proper authentication. Attackers could potentially execute commands, modify configurations, or access sensitive system information through CGI programs that inherit the cleared authentication context. This issue aligns with ATT&CK technique T1078.004, which covers valid accounts with compromised credentials, and represents a failure in proper privilege management during system operations. The vulnerability demonstrates a fundamental flaw in the server's session management and process isolation mechanisms.
Mitigation strategies for this vulnerability require immediate patching of affected Webmin installations to versions that properly handle environment variable cleanup during server restarts. System administrators should implement strict access controls and monitor for unauthorized local access attempts. Additionally, organizations should consider implementing process isolation techniques and regular security audits to detect similar issues in other web applications. The remediation process should include comprehensive testing to ensure that environment variables are properly cleared during server restart operations and that authentication contexts are appropriately invalidated. Regular vulnerability assessments and security configuration reviews are essential to prevent similar issues from emerging in other applications that may exhibit similar behavior patterns.