CVE-2021-31796
📋 TL;DR
This vulnerability in CyberArk Credential Provider allows attackers to decrypt credential files due to insufficient encryption key space. Attackers can realistically reduce possible keys to just one, enabling credential theft. Organizations using CyberArk Credential Provider versions before 12.1 are affected.
💻 Affected Systems
- CyberArk Credential Provider
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of all encrypted credentials stored in CyberArk, leading to lateral movement, privilege escalation, and full domain compromise.
Likely Case
Targeted credential theft from specific credential files, enabling unauthorized access to sensitive systems and data.
If Mitigated
Limited impact if credential files are stored in isolated, monitored environments with additional access controls.
🎯 Exploit Status
Exploitation requires access to credential files and knowledge of the encryption weakness. Public proof-of-concept code exists.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 12.1 and later
Vendor Advisory: https://www.cyberark.com/resources/blog
Restart Required: Yes
Instructions:
1. Download CyberArk Credential Provider version 12.1 or later from CyberArk support portal. 2. Backup existing credential files. 3. Install the updated version following CyberArk documentation. 4. Restart affected services/systems. 5. Re-encrypt existing credential files using the new version.
🔧 Temporary Workarounds
Credential File Isolation
allRestrict access to credential files using strict file permissions and access controls.
Windows: icacls "C:\Path\To\CredentialFiles" /deny Everyone:(R,W,X)
Linux: chmod 600 /path/to/credentialfiles && chown root:root /path/to/credentialfiles
Network Segmentation
allIsolate systems storing credential files from general network access.
🧯 If You Can't Patch
- Implement strict access controls and monitoring on all systems storing credential files
- Consider migrating credentials to alternative secure storage solutions until patching is possible
🔍 How to Verify
Check if Vulnerable:
Check CyberArk Credential Provider version. If version is below 12.1, system is vulnerable.Check Version:
Windows: Check installed programs in Control Panel or run 'wmic product get name,version' | findstr CyberArk. Linux: Check package manager or installed files for version information.Verify Fix Applied:
Verify installation of version 12.1 or later and confirm credential files have been re-encrypted with the updated version.📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to credential file locations
- Multiple failed decryption attempts
- Unusual process access to credential files
Network Indicators:
- Unusual outbound connections from systems storing credential files
- Traffic patterns suggesting credential extraction
SIEM Query:
source="*credential*" OR process="*CyberArk*" AND (event_type="access_denied" OR event_type="file_read")🔗 References
- http://packetstormsecurity.com/files/164023/CyberArk-Credential-File-Insufficient-Effective-Key-Space.html
- http://seclists.org/fulldisclosure/2021/Sep/1
- https://korelogic.com/Resources/Advisories/KL-001-2021-008.txt
- https://www.cyberark.com/resources/blog
- http://packetstormsecurity.com/files/164023/CyberArk-Credential-File-Insufficient-Effective-Key-Space.html
- http://seclists.org/fulldisclosure/2021/Sep/1
- https://korelogic.com/Resources/Advisories/KL-001-2021-008.txt
- https://www.cyberark.com/resources/blog
