ClearanceKit is a macOS security tool that intercepts file-system access events to enforce per-process file access policies via the Endpoint Security framework. In versions before 4.2, the enforcement mechanism only intercepted ES_EVENT_TYPE_AUTH_OPEN events, ignoring seven other file operation event types such as AUTH_RENAME and AUTH_UNLINK. This incomplete interception creates a missing authorization vulnerability (CWE-862), allowing any locally running process with low privileges to bypass the configured file access authorization (FAA) policies. Consequently, unauthorized file operations can occur without triggering denials or alerts, compromising system security. The fix introduced in version 4.2 subscribes to all relevant file operation events and routes them through the existing FAA policy evaluator, ensuring comprehensive enforcement. Additionally, the fix maintains compatibility with macOS XProtect by allowing certain system path events to proceed while triggering appropriate callbacks. The vulnerability has a CVSS 3.1 score of 8.7, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and requiring only low privileges and no user interaction. No known exploits are currently observed in the wild, and no workarounds are available, emphasizing the need for timely patching.

This vulnerability allows local attackers or malicious processes to bypass file access controls enforced by ClearanceKit, potentially leading to unauthorized reading, modification, renaming, or deletion of sensitive files. The breach of confidentiality could expose sensitive data, while integrity and availability impacts could disrupt critical system or application operations. Because the flaw affects multiple file operation types beyond just file opening, attackers have a broad attack surface to manipulate files undetected. Organizations relying on ClearanceKit for endpoint security on macOS are at risk of privilege escalation or data compromise. The vulnerability’s low complexity and lack of required user interaction increase the likelihood of exploitation in environments where ClearanceKit is deployed. This could undermine trust in endpoint protection and lead to data breaches, operational disruptions, or compliance violations.

The primary mitigation is to upgrade ClearanceKit to version 4.2 or later, which fully addresses the missing authorization by intercepting all relevant file operation events. Until upgrading, organizations should minimize the number of local users and processes with access to vulnerable systems to reduce attack vectors. Employing additional macOS native protections such as System Integrity Protection (SIP) and restricting execution of untrusted code can help limit exploitation. Monitoring file system activity for unusual rename or unlink operations may provide early detection, although the vulnerability allows bypassing some alerts. Organizations should also review and tighten ClearanceKit policy configurations to ensure least privilege principles are enforced. Coordinating with the vendor for any interim patches or guidance is recommended. Finally, maintaining robust endpoint detection and response (EDR) capabilities can help identify suspicious behavior stemming from exploitation attempts.