CVE-2021-26296
📋 TL;DR
Apache MyFaces Core uses cryptographically weak CSRF tokens in default configurations, allowing attackers to potentially predict future token values and trick users into performing unauthorized actions. This affects applications using Apache MyFaces Core versions 2.2.0-2.2.13, 2.3.0-2.3.7, 2.3-next-M1 to M4, and 3.0.0-RC1.
💻 Affected Systems
- Apache MyFaces Core
📦 What is this software?
Myfaces by Apache
Myfaces by Apache
Myfaces by Apache
Myfaces by Apache
Myfaces by Apache
Myfaces by Apache
Myfaces by Apache
⚠️ Risk & Real-World Impact
Worst Case
Attackers could perform CSRF attacks to execute privileged actions as authenticated users, potentially leading to data theft, account takeover, or unauthorized administrative changes.
Likely Case
Targeted CSRF attacks against specific users to perform actions within their privilege level, such as changing settings, making transactions, or modifying data.
If Mitigated
Limited impact with proper CSRF protections, strong session management, and additional authentication requirements for sensitive actions.
🎯 Exploit Status
Exploitation requires predicting CSRF tokens, which is difficult but possible due to weak cryptography. Attackers need to trick authenticated users into visiting malicious pages.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.2.14, 2.3.8, 3.0.0
Vendor Advisory: https://lists.apache.org/thread.html/r2b73e2356c6155e9ec78fdd8f72a4fac12f3e588014f5f535106ed9b%40%3Cannounce.apache.org%3E
Restart Required: Yes
Instructions:
1. Identify Apache MyFaces Core version. 2. Upgrade to patched version: 2.2.14, 2.3.8, or 3.0.0. 3. Update dependencies in your application. 4. Restart application server. 5. Test application functionality.
🔧 Temporary Workarounds
Implement Custom CSRF Protection
allReplace default CSRF token implementation with stronger cryptographic tokens or use additional CSRF protection mechanisms.
Enable SameSite Cookies
allConfigure session cookies with SameSite=Strict or SameSite=Lax attributes to mitigate CSRF attacks.
🧯 If You Can't Patch
- Implement additional CSRF protections like double-submit cookies or custom token validation
- Add re-authentication requirements for sensitive actions and implement strict referer checking
🔍 How to Verify
Check if Vulnerable:
Check application's Apache MyFaces Core version against affected versions. Review web.xml for CSRF configuration.Check Version:
Check Maven/Gradle dependencies or application server logs for Apache MyFaces Core versionVerify Fix Applied:
Verify upgraded to patched version (2.2.14, 2.3.8, or 3.0.0) and test CSRF protection functionality.📡 Detection & Monitoring
Log Indicators:
- Multiple failed CSRF token validations from same user
- Unexpected administrative actions from regular users
Network Indicators:
- Cross-origin requests with valid CSRF tokens
- Requests with predictable token patterns
SIEM Query:
source="web_server" AND (event="CSRF_TOKEN_VALIDATION_FAILED" OR event="UNAUTHORIZED_ACTION")🔗 References
- http://packetstormsecurity.com/files/161484/Apache-MyFaces-2.x-Cross-Site-Request-Forgery.html
- http://seclists.org/fulldisclosure/2021/Feb/66
- https://lists.apache.org/thread.html/r2b73e2356c6155e9ec78fdd8f72a4fac12f3e588014f5f535106ed9b%40%3Cannounce.apache.org%3E
- https://security.netapp.com/advisory/ntap-20210528-0007/
- http://packetstormsecurity.com/files/161484/Apache-MyFaces-2.x-Cross-Site-Request-Forgery.html
- http://seclists.org/fulldisclosure/2021/Feb/66
- https://lists.apache.org/thread.html/r2b73e2356c6155e9ec78fdd8f72a4fac12f3e588014f5f535106ed9b%40%3Cannounce.apache.org%3E
- https://security.netapp.com/advisory/ntap-20210528-0007/
