CVE-2005-2751 in Mac OS X
Summary
by MITRE
memberd in mac os x 10.4 up to 10.4.2 in certain situations does not quickly synchronize access control checks with changes in group membership which could allow users to access files and other resources after they have been removed from a group.
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Analysis
by VulDB Data Team • 06/11/2019
The vulnerability identified as CVE-2005-2751 affects memberd service in macOS X versions 10.4 through 10.4.2, representing a significant access control flaw that undermines the security model of the operating system. This issue resides in the fundamental mechanism responsible for managing group membership and access permissions within the macOS environment, specifically impacting how the system handles synchronization between group membership changes and access control evaluations.
The technical flaw manifests in the memberd daemon's failure to promptly propagate group membership updates to the access control subsystem. When a user is removed from a group, the system should immediately invalidate cached access control decisions that previously granted that user access to group-restricted resources. However, due to this synchronization delay, users who have been removed from groups can continue to access files and other protected resources that were previously restricted to that group membership. This represents a classic privilege escalation vulnerability where the system fails to enforce proper access control boundaries.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially compromise the integrity and confidentiality of sensitive data. Attackers who can identify this timing window can exploit the delay to maintain access to resources they should no longer have permission to access, potentially leading to data exfiltration, privilege escalation, or continued access to administrative resources. The vulnerability particularly affects environments where group membership changes occur frequently or where immediate access revocation is critical for security posture.
This vulnerability maps to CWE-284 Access Control Issues, specifically addressing inadequate access control enforcement where the system fails to properly synchronize access control decisions with changes in user permissions. From an ATT&CK perspective, this represents a privilege escalation technique through access control manipulation, potentially enabling adversaries to maintain persistence or escalate privileges within the macOS environment. The delayed synchronization creates a window of opportunity where the system's security model is temporarily compromised, allowing unauthorized access to resources that should be restricted.
Mitigation strategies for CVE-2005-2751 include immediate deployment of Apple's security patches for macOS X 10.4.3 and later versions, which address the synchronization issues in memberd service. Organizations should also implement monitoring for group membership changes and verify that access control decisions are properly enforced across the system. Regular security audits should validate that user access permissions are correctly synchronized, and system administrators should consider implementing additional access control layers or periodic access reviews to compensate for the vulnerability. The recommended approach involves ensuring that all systems are updated to patched versions and that access control policies are regularly validated to prevent exploitation of this timing-based access control flaw.