CVE-2021-28313
📋 TL;DR
CVE-2021-28313 is an elevation of privilege vulnerability in Microsoft's Diagnostics Hub Standard Collector Service. It allows authenticated attackers to execute arbitrary code with SYSTEM privileges by exploiting improper privilege management. This affects Windows systems where the Diagnostics Hub service is enabled.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Visual Studio by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM privileges, enabling installation of malware, data theft, and lateral movement across the network.
Likely Case
Local privilege escalation from a standard user account to SYSTEM, allowing attackers to bypass security controls and maintain persistence.
If Mitigated
Limited impact with proper patch management and least privilege principles, though still a significant risk if exploited.
🎯 Exploit Status
Exploit requires authenticated user access. Public proof-of-concept code is available, making exploitation straightforward for attackers with initial access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: April 2021 security updates (KB5001330 for Windows 10 20H2, KB5001337 for Windows 10 2004, etc.)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28313
Restart Required: Yes
Instructions:
1. Apply the April 2021 Windows security updates from Windows Update. 2. For enterprise environments, deploy through WSUS or Microsoft Endpoint Configuration Manager. 3. Restart systems after patch installation.
🔧 Temporary Workarounds
Disable Diagnostics Hub Service
windowsDisable the vulnerable service to prevent exploitation.
sc stop diagsvc
sc config diagsvc start= disabled
🧯 If You Can't Patch
- Implement strict least privilege principles to limit standard user access
- Monitor for suspicious service execution and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Windows version and if April 2021 security updates are installed. Vulnerable if running affected versions without patches.Check Version:
winver or systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify KB5001330 (or equivalent for your version) is installed via 'wmic qfe list' or 'Get-Hotfix -Id KB5001330' in PowerShell.📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with process creation from diaghost.exe or diagtrackrunner.exe with elevated privileges
- Unexpected service starts for Diagnostics Hub Standard Collector
Network Indicators:
- Unusual outbound connections from system processes post-exploitation
SIEM Query:
EventID=4688 AND (NewProcessName="*diaghost.exe" OR NewProcessName="*diagtrackrunner.exe") AND IntegrityLevel="System"🔗 References
- http://packetstormsecurity.com/files/162251/Microsoft-DiagHub-Privilege-Escalation.html
- http://seclists.org/fulldisclosure/2021/Apr/40
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28313
- http://packetstormsecurity.com/files/162251/Microsoft-DiagHub-Privilege-Escalation.html
- http://seclists.org/fulldisclosure/2021/Apr/40
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28313
