CVE-2021-23892
📋 TL;DR
This vulnerability allows local users on Linux systems running McAfee Endpoint Security to escalate privileges to root/admin level through a race condition exploit during installation. Attackers can execute arbitrary code by exploiting predictable temporary file locations. Only affects systems with McAfee Endpoint Security for Linux Threat Prevention and Firewall installed.
💻 Affected Systems
- McAfee Endpoint Security for Linux Threat Prevention and Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root-level access, allowing installation of persistent backdoors, data exfiltration, and lateral movement across the network.
Likely Case
Local privilege escalation leading to unauthorized administrative access on affected Linux endpoints.
If Mitigated
Limited impact with proper access controls and monitoring, though local users could still potentially exploit the vulnerability.
🎯 Exploit Status
Requires local access and knowledge of TOCTOU race condition exploitation techniques. Exploit involves manipulating temporary files during installation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.7.2 February 2021 Update
Vendor Advisory: https://kc.mcafee.com/corporate/index?page=content&id=SB10355
Restart Required: Yes
Instructions:
1. Download McAfee Endpoint Security for Linux 10.7.2 February 2021 Update from official sources. 2. Stop McAfee services. 3. Install the update package. 4. Restart the system. 5. Verify installation and restart McAfee services.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit local user accounts on affected systems to reduce attack surface
Monitor temporary directory
linuxImplement file integrity monitoring on temporary directories used by McAfee installation
# Example auditd rule: auditctl -w /tmp/mcafee_install -p wa -k mcafee_install
🧯 If You Can't Patch
- Implement strict access controls to limit local user accounts on affected systems
- Deploy file integrity monitoring to detect unauthorized changes to temporary directories
🔍 How to Verify
Check if Vulnerable:
Check McAfee Endpoint Security version: rpm -q MFEcma or dpkg -l | grep mcafeeCheck Version:
rpm -q MFEcma || dpkg -l | grep mcafeeVerify Fix Applied:
Verify version is 10.7.2 or later: rpm -q MFEcma | grep 10.7.2📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from McAfee installation directories
- Multiple rapid file operations in /tmp during McAfee operations
- Privilege escalation attempts from local user accounts
Network Indicators:
- Unusual outbound connections from McAfee processes post-exploitation
SIEM Query:
source="linux_audit" AND (process="*/tmp/*mcafee*" OR file_path="/tmp/*mcafee*") AND action="execve" OR action="open"