CVE-2025-24036: Microsoft Autoupdate Privilege Escalation

CVE-2025-24036 Overview

CVE-2025-24036 is an elevation of privilege vulnerability affecting Microsoft AutoUpdate (MAU) on macOS systems. This vulnerability allows a local attacker with low privileges to potentially escalate their privileges to a higher level, gaining unauthorized access to system resources and sensitive operations.

Critical Impact

A successful exploitation could allow attackers to elevate privileges on macOS systems running vulnerable versions of Microsoft AutoUpdate, potentially compromising the entire system.

Affected Products

• Microsoft AutoUpdate for macOS (all vulnerable versions)

Discovery Timeline

• 2025-02-11 - CVE-2025-24036 published to NVD
• 2025-02-14 - Last updated in NVD database

Technical Details for CVE-2025-24036

Vulnerability Analysis

This elevation of privilege vulnerability resides in Microsoft AutoUpdate (MAU), the update mechanism used by Microsoft Office applications on macOS. The vulnerability stems from a Time-of-Check Time-of-Use (TOCTOU) race condition (CWE-367), where there is a gap between when a resource is checked and when it is used. During this window, an attacker could manipulate the state of the resource to gain elevated privileges.

The attack requires local access to the target system and involves exploiting the timing window during the update process. While the attack complexity is high due to the precise timing required, successful exploitation does not require user interaction, making it a persistent threat vector for systems running vulnerable versions of MAU.

Root Cause

The root cause of this vulnerability is a Time-of-Check Time-of-Use (TOCTOU) race condition (CWE-367). This occurs when Microsoft AutoUpdate performs security validation checks on a resource but then uses that resource in a subsequent operation without adequate protection against concurrent modification. An attacker with local access can exploit this timing window by modifying the resource between the check and use phases.

Attack Vector

The attack vector for CVE-2025-24036 is local, meaning an attacker must have some level of access to the target macOS system. The attacker would need to:

1. Gain local access to a macOS system running Microsoft AutoUpdate
2. Monitor the update process to identify the timing window
3. Manipulate system resources during the TOCTOU gap
4. Successfully escalate privileges through the race condition

The attack does not require user interaction but does require precise timing to exploit the race condition successfully.

Detection Methods for CVE-2025-24036

Indicators of Compromise

• Unexpected privilege escalation events associated with the Microsoft AutoUpdate process (msupdate)
• Suspicious file modifications in Microsoft AutoUpdate directories during update operations
• Anomalous process behavior or child process spawning from MAU components with elevated privileges

Detection Strategies

• Monitor process execution chains involving Microsoft AutoUpdate for unexpected privilege transitions
• Implement file integrity monitoring on MAU installation directories and related configuration files
• Use endpoint detection and response (EDR) solutions to detect race condition exploitation attempts
• Review system logs for unusual authentication or authorization events tied to MAU processes

Monitoring Recommendations

• Enable detailed logging for Microsoft AutoUpdate operations on macOS endpoints
• Configure alerts for privilege escalation attempts originating from trusted Microsoft processes
• Monitor for rapid file access patterns that may indicate TOCTOU exploitation attempts

How to Mitigate CVE-2025-24036

Immediate Actions Required

• Apply the latest security update from Microsoft for Microsoft AutoUpdate immediately
• Review and restrict local access to systems running vulnerable versions of MAU
• Implement application whitelisting to prevent unauthorized code execution during the update process
• Monitor affected systems for signs of exploitation while patches are being deployed

Patch Information

Microsoft has released a security update to address this vulnerability. Organizations should consult the Microsoft Security Update Guide for CVE-2025-24036 for detailed patch information and deployment guidance. It is recommended to update Microsoft AutoUpdate to the latest available version through Microsoft's official channels.

Workarounds

• Restrict local user access to only trusted personnel on systems with Microsoft AutoUpdate installed
• Consider temporarily disabling automatic updates and performing manual updates in a controlled environment until patching is complete
• Implement additional access controls and monitoring on MAU-related directories and processes