CVE-2021-23882
📋 TL;DR
This vulnerability allows local administrators on Windows systems to prevent proper installation of McAfee Endpoint Security (ENS) files during clean installations by placing specially crafted files in the installation directory. This affects organizations using ENS for Windows prior to version 10.7.0 February 2021 Update. The vulnerability does not affect upgrades from existing installations.
💻 Affected Systems
- McAfee Endpoint Security (ENS) for Windows
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local administrators could prevent ENS from installing correctly, leaving systems without endpoint protection and potentially enabling further attacks.
Likely Case
Malicious local administrators could intentionally disrupt ENS installation to bypass security controls on their systems.
If Mitigated
With proper access controls and monitoring of local administrator activities, the impact is limited to potential installation failures that can be detected and remediated.
🎯 Exploit Status
Exploitation requires local administrator access and knowledge of the specific file placement technique. No public exploit code has been identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ENS 10.7.0 February 2021 Update or later
Vendor Advisory: https://kc.mcafee.com/corporate/index?page=content&id=SB10345
Restart Required: Yes
Instructions:
1. Download ENS 10.7.0 February 2021 Update or later from McAfee. 2. Deploy the update through your endpoint management system. 3. Restart affected systems to complete installation.
🔧 Temporary Workarounds
Restrict local administrator privileges
windowsLimit the number of users with local administrator access to reduce attack surface
Monitor installation directories
windowsImplement file integrity monitoring on ENS installation directories
🧯 If You Can't Patch
- Implement least privilege access controls to limit local administrator accounts
- Monitor for failed ENS installations and investigate any anomalies
🔍 How to Verify
Check if Vulnerable:
Check ENS version: If version is earlier than 10.7.0 February 2021 Update, the system is vulnerable.Check Version:
Check McAfee Agent version via: "C:\Program Files\McAfee\Agent\cmdagent.exe" -iVerify Fix Applied:
Verify ENS version is 10.7.0 February 2021 Update or later and check installation logs for successful completion.📡 Detection & Monitoring
Log Indicators:
- Failed ENS installation attempts
- Access denied errors in ENS installation logs
- Unexpected files in ENS installation directories
Network Indicators:
- No network indicators as this is a local vulnerability
SIEM Query:
Search for McAfee installation failures or access denied events in endpoint security logs