CVE-2021-25249
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in Trend Micro security products that allows a local attacker with low-privileged code execution to escalate privileges on affected systems. The vulnerability affects Trend Micro Apex One, OfficeScan XG SP1, and Worry-Free Business Security installations.
💻 Affected Systems
- Trend Micro Apex One
- Trend Micro OfficeScan XG SP1
- Trend Micro Worry-Free Business Security
📦 What is this software?
Apex One by Trendmicro
Officescan by Trendmicro
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains full SYSTEM/root privileges, enabling complete system compromise, data theft, and persistence establishment.
Likely Case
Privilege escalation from limited user to administrator/system-level access, allowing installation of malware, disabling security controls, and lateral movement.
If Mitigated
Attack fails due to proper patch deployment, limited user privileges, or security controls preventing initial low-privileged code execution.
🎯 Exploit Status
Requires local access and ability to execute code with low privileges first. The vulnerability is in the Trend Micro security agent software.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Trend Micro advisories for specific version updates
Vendor Advisory: https://success.trendmicro.com/solution/000284202
Restart Required: Yes
Instructions:
1. Review Trend Micro advisories for specific patch versions. 2. Update affected Trend Micro products to latest patched versions. 3. Restart systems to apply updates. 4. Verify patch installation through product console.
🔧 Temporary Workarounds
Restrict local user privileges
windowsLimit user accounts to minimum necessary privileges to reduce attack surface for initial low-privileged code execution.
Use Windows Group Policy or local security policy to restrict user privileges
Application control/whitelisting
windowsImplement application control to prevent unauthorized code execution on endpoints.
Configure Windows AppLocker or similar application control solutions
🧯 If You Can't Patch
- Implement strict least privilege access controls to limit initial attack surface
- Deploy additional endpoint security controls to detect and prevent privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Trend Micro product version against affected versions listed in vendor advisoriesCheck Version:
Check Trend Micro agent version through product console or Windows Programs and FeaturesVerify Fix Applied:
Verify Trend Micro product is updated to patched version through product console or management interface📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events in Windows Security logs
- Trend Micro agent crash or unexpected behavior logs
- Process creation with unexpected parent-child relationships
Network Indicators:
- Unusual outbound connections from Trend Micro agent processes
- Lateral movement attempts following potential privilege escalation
SIEM Query:
EventID=4688 AND NewProcessName contains 'cmd.exe' OR 'powershell.exe' AND ParentProcessName contains 'Trend Micro'🔗 References
- https://success.trendmicro.com/solution/000284202
- https://success.trendmicro.com/solution/000284205
- https://success.trendmicro.com/solution/000284206
- https://www.zerodayinitiative.com/advisories/ZDI-21-119/
- https://success.trendmicro.com/solution/000284202
- https://success.trendmicro.com/solution/000284205
- https://success.trendmicro.com/solution/000284206
- https://www.zerodayinitiative.com/advisories/ZDI-21-119/
