CVE-2021-1728
📋 TL;DR
CVE-2021-1728 is an elevation of privilege vulnerability in Microsoft System Center Operations Manager (SCOM). It allows authenticated attackers to execute arbitrary code with SYSTEM privileges on affected servers. This affects organizations using vulnerable versions of SCOM for IT infrastructure monitoring.
💻 Affected Systems
- Microsoft System Center Operations Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of SCOM servers leading to domain admin access, lateral movement across the network, and installation of persistent backdoors.
Likely Case
Attackers with initial access to SCOM servers gain full control, allowing them to manipulate monitoring data, disable alerts, and pivot to other systems.
If Mitigated
With proper network segmentation and least privilege access, impact is limited to the SCOM server itself without lateral movement capabilities.
🎯 Exploit Status
Exploitation requires authenticated access to SCOM. Public proof-of-concept code exists, making exploitation straightforward for attackers with initial access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: SCOM 2019 UR3, SCOM 2016 UR10, SCOM 2012 R2 UR19
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1728
Restart Required: Yes
Instructions:
1. Download appropriate update rollup from Microsoft Update Catalog. 2. Apply update to all SCOM management servers. 3. Restart SCOM services. 4. Verify all components are updated.
🔧 Temporary Workarounds
Restrict SCOM Management Server Access
windowsLimit network access to SCOM management servers to only authorized administrators and required systems
Use Windows Firewall or network ACLs to restrict access to SCOM ports (TCP 5723, 5724)
Implement Least Privilege
windowsEnsure SCOM service accounts and administrators have only necessary permissions
Review and restrict SCOM administrator accounts using Active Directory security groups
🧯 If You Can't Patch
- Isolate SCOM servers in a separate network segment with strict access controls
- Implement enhanced monitoring for suspicious activity on SCOM servers and review SCOM administrator account usage
🔍 How to Verify
Check if Vulnerable:
Check SCOM version via Operations Console: Administration > Product Knowledge > About System Center Operations ManagerCheck Version:
Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like '*Operations Manager*'} | Select-Object Name, VersionVerify Fix Applied:
Verify update rollup is installed in Windows Update history and SCOM version matches patched versions📡 Detection & Monitoring
Log Indicators:
- Unusual SCOM service account activity
- Unexpected process execution with SYSTEM privileges on SCOM servers
- Changes to SCOM management packs or monitoring rules
Network Indicators:
- Unusual connections to SCOM management server ports from non-admin systems
- Lateral movement attempts originating from SCOM servers
SIEM Query:
EventID=4688 AND ProcessName LIKE '%powershell%' OR '%cmd%' AND SubjectUserName LIKE '%SCOM%' AND NewProcessName NOT IN (expected SCOM processes)