Summary

Microsoft was notified that an elevation of privilege vulnerability exists in Windows Update, potentially enabling an attacker with basic user privileges to reintroduce previously mitigated vulnerabilities or circumvent some features of Virtualization Based Security (VBS). However, an attacker attempting to exploit this vulnerability requires additional interaction by a privileged user to be successful.

Microsoft is developing a security update to mitigate this threat, but it is not yet available. Guidance to help customers reduce the risks associated with this vulnerability and to protect their systems until the mitigation is available in a Windows security update is provided in the Recommended Actions section of this CVE.

This CVE will be updated, and customers will be notified when the official mitigation is available in a Windows security update. We highly encourage customers to subscribe to Security Update Guide notifications to receive an alert when this update occurs.

Details

A security researcher informed Microsoft of an elevation of privilege vulnerability in Windows Update potentially enabling an attacker with basic user privileges to reintroduce previously mitigated vulnerabilities or circumvent some features of VBS. For exploitation to succeed, an attacker must trick or convince an Administrator or a user with delegated permissions into performing a system restore which inadvertently triggers the vulnerability.

Microsoft is developing a security update that will mitigate this vulnerability, but it is not yet available. This CVE will be updated with new information and links to the security updates once available. We highly encourage customers subscribe to Security Update Guide notifications to be alerted of updates. See Microsoft Technical Security Notifications and Security Update Guide Notification System News: Create your profile now – Microsoft Security Response Center.

Microsoft is not aware of any attempts to exploit this vulnerability. However, a public presentation regarding this vulnerability was hosted at BlackHat on August 7, 2024. The presentation was appropriately coordinated with Microsoft but may change the threat landscape. Customers concerned with these risks should reference the guidance provided in the Recommended Actions section to protect their systems.

Recommended Actions

The following recommendations do not mitigate the vulnerability but can be used to reduce the risk of exploitation until the security update is available.

• Configure “Audit Object Access” settings to monitor attempts to access files, such as handle creation, read / write operations, or modifications to security descriptors.

  • Audit File System - Windows 10 | Microsoft Learn
  • Apply a basic audit policy on a file or folder - Windows 10 | Microsoft Learn

• Audit users with permission to perform Update and Restore operations to ensure only the appropriate users can perform these operations.

  • Audit: Audit the use of Backup and Restore privilege (Windows 10) - Windows 10 | Microsoft Learn

• Implement an Access Control List or Discretionary Access Control Lists to restrict the access or modification of Update files and perform Restore operations to appropriate users, for example administrators only.

  • Access Control overview | Microsoft Learn
  • Discretionary Access Control Lists (DACL)

• Auditing sensitive privileges used to identify access, modification, or replacement of Update related files could help indicate attempts to exploit this vulnerability.

  • Audit Sensitive Privilege Use - Windows 10 | Microsoft Learn