CVE-2005-0198 in UW-IMAP
Summary
by MITRE
A logic error in the CRAM-MD5 code for the University of Washington IMAP (UW-IMAP) server, when Challenge-Response Authentication Mechanism with MD5 (CRAM-MD5) is enabled, does not properly enforce all the required conditions for successful authentication, which allows remote attackers to authenticate as arbitrary users.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2005-0198 resides within the University of Washington IMAP server implementation, specifically affecting the CRAM-MD5 authentication mechanism. This authentication method operates on a challenge-response protocol where the server sends a challenge to the client, and the client responds with a hash value derived from the challenge and the user's password. The flaw manifests as a logic error in the server-side validation code that processes these authentication exchanges, creating a potential security bypass.
The technical flaw stems from improper validation of authentication conditions within the CRAM-MD5 implementation. When CRAM-MD5 is enabled on the UW-IMAP server, the authentication logic fails to rigorously verify all necessary conditions required for successful user authentication. This incomplete validation allows malicious actors to exploit the system by crafting specially formatted authentication requests that bypass normal authentication checks. The vulnerability essentially creates a condition where the server accepts authentication attempts without properly validating the cryptographic integrity of the response, enabling unauthorized access.
This vulnerability has significant operational impact as it fundamentally undermines the authentication security model of the IMAP server. Remote attackers can exploit this weakness to authenticate as any user within the system without possessing valid credentials, potentially gaining access to sensitive email communications, user data, and system resources. The implications extend beyond simple credential theft, as successful exploitation could lead to complete system compromise, data exfiltration, and persistent access to network resources. The vulnerability affects organizations relying on UW-IMAP servers with CRAM-MD5 enabled, particularly those with email infrastructure that depends on this authentication mechanism.
Organizations should immediately disable CRAM-MD5 authentication on affected UW-IMAP servers and implement alternative authentication methods such as SASL with stronger cryptographic mechanisms or TLS-encrypted authentication. System administrators should also consider upgrading to patched versions of the UW-IMAP server software, as this vulnerability represents a fundamental flaw in the authentication logic that cannot be adequately mitigated through configuration changes alone. Security monitoring should be enhanced to detect unusual authentication patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-284 Access Control Issues and maps to ATT&CK technique T1078 Valid Accounts, as it allows adversaries to leverage valid authentication mechanisms to gain unauthorized access to systems. Organizations should also implement network segmentation and access controls to limit the potential impact of successful exploitation, particularly in environments where IMAP services are exposed to untrusted networks.