CVE-2021-42102
📋 TL;DR
This vulnerability allows a local attacker with low-privileged code execution to escalate privileges on Trend Micro Apex One installations. It affects both on-premise Apex One and cloud-based Apex One as a Service deployments. Attackers can exploit this to gain higher system privileges than originally granted.
💻 Affected Systems
- Trend Micro Apex One
- Trend Micro Apex One as a Service
📦 What is this software?
Apex One by Trendmicro
Apex One by Trendmicro
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with administrative privileges, enabling installation of persistent malware, data theft, and lateral movement across the network.
Likely Case
Local privilege escalation allowing attackers to bypass security controls, install additional malware, and maintain persistence on compromised systems.
If Mitigated
Limited impact if proper endpoint security controls, least privilege principles, and network segmentation are implemented.
🎯 Exploit Status
Requires local access with low-privileged execution first. The vulnerability is in the DLL search path mechanism, making exploitation relatively straightforward for attackers with initial access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2019 (11.0.0.2266) and 2020 (14.0.0.2266) hotfix patches
Vendor Advisory: https://success.trendmicro.com/solution/000289229
Restart Required: Yes
Instructions:
1. Download the appropriate hotfix from Trend Micro support portal. 2. Apply the hotfix to all affected Apex One agents. 3. Restart the systems to complete the installation. 4. Verify the patch is applied successfully.
🔧 Temporary Workarounds
Restrict local user privileges
windowsImplement least privilege principles to limit local user account permissions, reducing the impact of initial low-privileged access.
Enable application whitelisting
windowsUse application control policies to prevent unauthorized code execution from non-standard locations.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate systems running vulnerable versions
- Enhance monitoring for privilege escalation attempts and unusual process behavior
🔍 How to Verify
Check if Vulnerable:
Check Apex One agent version in Trend Micro Control Manager or via the agent interface. Versions prior to 11.0.0.2266 (2019) or 14.0.0.2266 (2020) are vulnerable.Check Version:
Check via Trend Micro Control Manager or agent properties. No single command available as it varies by deployment.Verify Fix Applied:
Verify agent version shows 11.0.0.2266 or higher for 2019, or 14.0.0.2266 or higher for 2020 in the Apex One management console.📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from non-standard directories
- Privilege escalation attempts in Windows security logs
- Apex One service loading DLLs from unexpected locations
Network Indicators:
- Unusual outbound connections from Apex One agent processes
- Lateral movement attempts following local compromise
SIEM Query:
Process creation where parent process is Apex One agent and command line contains suspicious DLL loading patterns