CVE-2020-3766
📋 TL;DR
CVE-2020-3766 is an insecure file permissions vulnerability in Adobe Genuine Integrity Service that allows local attackers to escalate privileges by manipulating files with overly permissive access controls. This affects users running Adobe Genuine Integrity Service version 6.4 and earlier on Windows systems. Successful exploitation could allow attackers to gain elevated system privileges.
💻 Affected Systems
- Adobe Genuine Integrity Service
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains SYSTEM/administrator privileges, enabling complete system compromise, installation of malware, data theft, and persistence mechanisms.
Likely Case
Local user or malware with limited privileges escalates to administrator rights to bypass security controls and install additional payloads.
If Mitigated
Attack fails due to proper file permissions, user account control, or security software blocking unauthorized file modifications.
🎯 Exploit Status
Exploitation requires local access to the system. The vulnerability involves insecure file permissions that can be manipulated by local users.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 6.5 and later
Vendor Advisory: https://helpx.adobe.com/security/products/integrity_service/apsb20-12.html
Restart Required: Yes
Instructions:
1. Open Adobe Creative Cloud application. 2. Navigate to the 'Apps' section. 3. Check for updates to Adobe Genuine Integrity Service. 4. Update to version 6.5 or later. 5. Restart the system to ensure the update is fully applied.
🔧 Temporary Workarounds
Remove vulnerable service
windowsUninstall Adobe Genuine Integrity Service if not required
Control Panel > Programs > Uninstall a program > Select Adobe Genuine Integrity Service > Uninstall
Restrict file permissions
windowsManually adjust file permissions for Adobe Genuine Integrity Service files to restrict write access
icacls "C:\Program Files (x86)\Common Files\Adobe\AdobeGCClient\" /deny Users:(OI)(CI)W
🧯 If You Can't Patch
- Implement strict least privilege principles for user accounts
- Deploy application whitelisting to prevent unauthorized file modifications
🔍 How to Verify
Check if Vulnerable:
Check Adobe Genuine Integrity Service version in Control Panel > Programs and Features or via command: wmic product where name="Adobe Genuine Integrity Service" get versionCheck Version:
wmic product where name="Adobe Genuine Integrity Service" get versionVerify Fix Applied:
Verify version is 6.5 or higher using same method as checking vulnerability📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing unauthorized file modifications in Adobe Genuine Integrity Service directories
- Security logs showing privilege escalation attempts
Network Indicators:
- No network indicators as this is a local vulnerability
SIEM Query:
EventID=4688 AND ProcessName LIKE '%AdobeGCClient%' AND NewProcessName LIKE '%cmd.exe%' OR NewProcessName LIKE '%powershell.exe%'