CVE-2020-7266
📋 TL;DR
This vulnerability allows local users on Windows systems running McAfee VirusScan Enterprise to escalate privileges by manipulating symbolic links. Attackers can delete files they shouldn't have access to by redirecting McAfee's delete operations through malicious scripts. Only affects McAfee VSE users on Windows prior to specific patch levels.
💻 Affected Systems
- McAfee VirusScan Enterprise (VSE)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through deletion of critical system files, configuration files, or security software components, potentially leading to persistent backdoors or system instability.
Likely Case
Targeted deletion of sensitive user or application data, disruption of business operations, or deletion of security logs to cover tracks of other malicious activities.
If Mitigated
Limited impact due to proper access controls, file integrity monitoring, and restricted local user privileges preventing malicious script execution.
🎯 Exploit Status
Requires local access and ability to run scripts/programs. Symbolic link manipulation requires specific programming knowledge but is well-documented technique.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.8 Patch 14 Hotfix 116778
Vendor Advisory: https://kc.mcafee.com/corporate/index?page=content&id=SB10316
Restart Required: Yes
Instructions:
1. Download Hotfix 116778 from McAfee support portal. 2. Close all applications. 3. Run the installer as administrator. 4. Restart the system when prompted. 5. Verify installation in McAfee console.
🔧 Temporary Workarounds
Restrict Symbolic Link Creation
windowsConfigure Windows security policy to restrict creation of symbolic links to administrators only
gpedit.msc -> Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> User Rights Assignment -> 'Create symbolic links' -> Remove all users except Administrators
Limit Local User Privileges
windowsEnsure standard users cannot execute scripts or programs that could manipulate symbolic links
Group Policy: Computer Configuration -> Administrative Templates -> System -> Scripts -> 'Run logon scripts visible' -> Disabled
Restrict software installation via AppLocker or similar
🧯 If You Can't Patch
- Implement strict least privilege access controls to prevent local users from running unauthorized scripts/programs
- Deploy file integrity monitoring to detect unauthorized file deletions and alert on symbolic link creation
🔍 How to Verify
Check if Vulnerable:
Check McAfee VSE version in About dialog or registry: HKEY_LOCAL_MACHINE\SOFTWARE\McAfee\DesktopProtection - ProductVersion valueCheck Version:
reg query "HKLM\SOFTWARE\McAfee\DesktopProtection" /v ProductVersionVerify Fix Applied:
Verify version is 8.8.0.14 or higher with Hotfix 116778 applied. Check McAfee console for patch status.📡 Detection & Monitoring
Log Indicators:
- Windows Security Event ID 4663 (File deletion attempts) on protected files
- McAfee logs showing unexpected file deletion operations
- Windows Event ID 4688 (Process creation) for suspicious script execution
Network Indicators:
- No network indicators - local exploit only
SIEM Query:
EventID=4663 AND ObjectName CONTAINS '\??\' AND AccessMask=0x10000 | OR | EventID=4688 AND NewProcessName CONTAINS '.vbs' OR '.ps1' OR '.bat' AND SubjectUserName NOT IN (admin_users)