CVE-2013-2057
📋 TL;DR
This vulnerability in YaBB forum software allows attackers to include local files via the 'guestlanguage' cookie parameter, potentially leading to remote code execution. It affects all YaBB installations through version 2.5.2. Attackers can exploit this without authentication to compromise vulnerable systems.
💻 Affected Systems
- YaBB (Yet another Bulletin Board)
📦 What is this software?
Yabb by Yabb
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and installation of persistent backdoors.
Likely Case
Local file inclusion allowing sensitive file disclosure (configuration files, passwords) and potential code execution.
If Mitigated
Limited impact with proper input validation and file inclusion restrictions in place.
🎯 Exploit Status
Simple cookie manipulation required. Public exploit code and details available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: YaBB 2.5.3 and later
Vendor Advisory: http://www.yabbforum.com/community/index.php?topic=316.0
Restart Required: No
Instructions:
1. Download YaBB 2.5.3 or later from official source. 2. Backup current installation. 3. Replace vulnerable files with patched versions. 4. Verify installation works correctly.
🔧 Temporary Workarounds
Input Validation Filter
allAdd input validation for guestlanguage cookie parameter to prevent directory traversal
Modify YaBB source to validate guestlanguage parameter against allowed values only
Web Application Firewall Rule
allBlock malicious cookie patterns containing directory traversal sequences
Add WAF rule to block cookies containing '../' or similar traversal patterns
🧯 If You Can't Patch
- Implement strict input validation for all cookie parameters
- Restrict file inclusion to specific allowed directories only
🔍 How to Verify
Check if Vulnerable:
Check YaBB version in admin panel or by examining source files. Versions 2.5.2 and earlier are vulnerable.Check Version:
Check YaBB/version.txt or admin panel version displayVerify Fix Applied:
Verify version is 2.5.3 or later. Test cookie manipulation attempts are properly rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual cookie values containing '../' or similar patterns
- Multiple failed file inclusion attempts
- Access to sensitive system files via web requests
Network Indicators:
- HTTP requests with manipulated guestlanguage cookie values
- Traffic patterns showing directory traversal attempts
SIEM Query:
web_cookie:*guestlanguage* AND (web_cookie:*../* OR web_cookie:*..\*)🔗 References
- http://www.openwall.com/lists/oss-security/2013/05/05/1
- http://www.securityfocus.com/bid/59643
- https://exchange.xforce.ibmcloud.com/vulnerabilities/84034
- http://www.openwall.com/lists/oss-security/2013/05/05/1
- http://www.securityfocus.com/bid/59643
- https://exchange.xforce.ibmcloud.com/vulnerabilities/84034
