CVE-2014-6331 in Windows
Summary
by MITRE
Microsoft Active Directory Federation Services (AD FS) 2.0, 2.1, and 3.0, when a configured SAML Relying Party lacks a sign-out endpoint, does not properly process logoff actions, which makes it easier for remote attackers to obtain access by leveraging an unattended workstation, aka "Active Directory Federation Services Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 12/14/2024
This vulnerability resides in Microsoft Active Directory Federation Services implementations across versions 2.0, 2.1, and 3.0 where the authentication system fails to properly handle logoff operations when SAML relying parties are configured without sign-out endpoints. The flaw creates a security gap that allows remote attackers to exploit unattended workstations by leveraging the improper logoff processing mechanism. From a technical perspective, when a user attempts to log off from a system utilizing AD FS for authentication, the service does not adequately invalidate the user session or properly terminate the authentication context if the relying party has not defined a sign-out endpoint. This behavior creates a window of opportunity where authentication tokens or session information may remain active even after a user believes they have logged out, particularly on unattended systems where the vulnerability can be exploited without requiring additional authentication credentials.
The operational impact of this vulnerability extends beyond simple session management issues and represents a significant information disclosure risk within enterprise authentication environments. When a user accesses a system through AD FS and subsequently logs off without proper endpoint validation, the system may maintain active authentication contexts that could be leveraged by attackers who gain physical or network access to the unattended workstation. This weakness directly aligns with CWE-200, which addresses information disclosure vulnerabilities, and creates conditions where sensitive authentication information remains accessible to unauthorized parties. The vulnerability is particularly concerning in enterprise environments where users may leave workstations unattended for extended periods, as it effectively undermines the security principle of proper session termination and access control enforcement.
From an attack perspective, this vulnerability enables what is classified as a session hijacking or token reuse attack pattern that aligns with ATT&CK technique T1567.002 for "Modify Authentication Token." Attackers can exploit the incomplete logoff process by accessing unattended systems where the AD FS service has not properly cleared authentication state information. The vulnerability essentially allows attackers to maintain access to systems that users believe they have properly logged out of, creating a persistent threat vector that could be exploited for lateral movement within networks or for privilege escalation attacks. The security implications are compounded by the fact that this issue affects multiple versions of AD FS, meaning organizations with legacy systems may be particularly vulnerable, and the exploitation requires minimal technical expertise beyond basic network access.
The mitigation strategies for this vulnerability involve implementing proper SAML relying party configuration with defined sign-out endpoints, which directly addresses the root cause of the issue. Organizations should ensure that all SAML relying parties configured within their AD FS environments include proper sign-out endpoint definitions to enable complete session termination. Microsoft released security updates that address this specific vulnerability, and organizations should implement these patches immediately. Additionally, network administrators should consider implementing session timeout policies and monitoring for unusual authentication patterns that might indicate exploitation attempts. The remediation process requires careful configuration review of all AD FS relying party trusts to ensure proper endpoint definitions exist, and organizations should conduct regular security assessments to verify that authentication session management is functioning correctly across their federation services.