CVE-2021-31854
📋 TL;DR
This CVE describes a local command injection vulnerability in McAfee Agent for Windows that allows authenticated local users to execute arbitrary code by placing malicious files in specific folders. Successful exploitation could lead to privilege escalation and full system compromise. Only Windows systems running vulnerable McAfee Agent versions are affected.
💻 Affected Systems
- McAfee Agent (MA) for Windows
📦 What is this software?
Agent by Mcafee
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains SYSTEM/root privileges, installs persistent backdoors, exfiltrates sensitive data, and moves laterally across the network.
Likely Case
Local authenticated attacker escalates privileges to SYSTEM level, potentially installing malware or accessing protected system resources.
If Mitigated
With proper access controls and monitoring, exploitation attempts are detected and blocked before significant damage occurs.
🎯 Exploit Status
Exploitation requires local authenticated access and knowledge of the McAfee Agent deployment feature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.7.5 or later
Vendor Advisory: https://kc.mcafee.com/corporate/index?page=content&id=SB10378
Restart Required: Yes
Instructions:
1. Download McAfee Agent 5.7.5 or later from official McAfee sources. 2. Deploy the update through your management console or manually install. 3. Restart affected systems to complete the update.
🔧 Temporary Workarounds
Restrict file permissions
windowsLimit write access to McAfee Agent directories to prevent malicious file placement
icacls "C:\Program Files\McAfee\Agent\" /deny Users:(OI)(CI)W
Disable deployment feature
windowsTemporarily disable the System Tree deployment feature if not required
Disable via McAfee ePolicy Orchestrator console or local configuration
🧯 If You Can't Patch
- Implement strict access controls to limit who can write to McAfee Agent directories
- Enable detailed auditing and monitoring of file creation in McAfee Agent folders
🔍 How to Verify
Check if Vulnerable:
Check McAfee Agent version: Open McAfee Agent UI or check registry at HKLM\SOFTWARE\McAfee\Agent\CurrentVersionCheck Version:
reg query "HKLM\SOFTWARE\McAfee\Agent" /v CurrentVersionVerify Fix Applied:
Verify version is 5.7.5 or higher and check that the vulnerability is listed as fixed in the patch notes📡 Detection & Monitoring
Log Indicators:
- Unexpected file creation in McAfee Agent directories
- Suspicious process execution from McAfee folders
- Failed attempts to write to protected directories
Network Indicators:
- Outbound connections from McAfee Agent processes to unexpected destinations
- Reverse shell connections originating from systems with McAfee Agent
SIEM Query:
Process Creation where (Image contains 'cleanup.exe' OR ParentImage contains 'McAfee') AND CommandLine contains suspicious patterns