CVE-2025-49665
📋 TL;DR
A race condition vulnerability in Workspace Broker allows authenticated attackers to escalate privileges on local systems. This affects systems running vulnerable versions of Microsoft Workspace Broker where an attacker already has some level of access. The vulnerability enables local privilege escalation by exploiting improper synchronization of shared resources.
💻 Affected Systems
- Microsoft Workspace Broker
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, allowing complete control over the affected system and potential lateral movement within the network.
Likely Case
Local privilege escalation from standard user to administrator/system-level privileges on the compromised machine.
If Mitigated
Limited impact with proper access controls, network segmentation, and monitoring in place to detect and contain privilege escalation attempts.
🎯 Exploit Status
Exploitation requires authenticated access and precise timing due to race condition nature. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific patch versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-49665
Restart Required: Yes
Instructions:
1. Review Microsoft Security Update Guide for CVE-2025-49665
2. Apply the latest security updates from Microsoft
3. Restart affected systems to complete installation
4. Verify patch installation through Windows Update history
🔧 Temporary Workarounds
Restrict Local Access
windowsLimit local user access to systems running Workspace Broker to reduce attack surface
Disable Unnecessary Services
windowsDisable Workspace Broker service if not required for business operations
sc stop "WorkspaceBroker"
sc config "WorkspaceBroker" start= disabled
🧯 If You Can't Patch
- Implement strict least privilege access controls to limit damage from privilege escalation
- Deploy endpoint detection and response (EDR) solutions to monitor for suspicious privilege escalation behavior
🔍 How to Verify
Check if Vulnerable:
Check if Workspace Broker service is running and verify system is unpatched via Windows Update historyCheck Version:
sc query "WorkspaceBroker"Verify Fix Applied:
Verify patch installation in Windows Update history and confirm Workspace Broker service version📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events in Windows Security logs
- Multiple rapid access attempts to Workspace Broker resources
- Process creation with elevated privileges from non-admin accounts
Network Indicators:
- Local system calls to Workspace Broker components with timing patterns indicative of race conditions
SIEM Query:
EventID=4688 AND NewProcessName CONTAINS "*" AND SubjectUserName NOT IN (admin_users) AND TokenElevationType=%%1938