CVE-2016-3735
📋 TL;DR
CVE-2016-3735 is a predictable password reset token vulnerability in Piwigo image gallery software. When certain criteria aren't met, Piwigo uses PHP's mt_rand() function to generate password reset tokens, which can be predicted by recovering the seed. This allows unauthenticated attackers to take over administrator accounts if they know the administrator's email address.
💻 Affected Systems
- Piwigo
📦 What is this software?
Piwigo by Piwigo
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of administrator account leading to full control of the Piwigo installation, potential data theft, and website defacement.
Likely Case
Administrator account takeover allowing unauthorized access to sensitive images, user data, and gallery management functions.
If Mitigated
No impact if patched or if password reset functionality is disabled for administrator accounts.
🎯 Exploit Status
Exploitation requires knowledge of administrator email address and ability to predict mt_rand() output based on seed recovery.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.1 and later
Vendor Advisory: http://piwigo.org/release-2.8.1
Restart Required: No
Instructions:
1. Backup your Piwigo installation and database. 2. Download Piwigo 2.8.1 or later from piwigo.org. 3. Replace existing Piwigo files with new version. 4. Run the upgrade script if prompted. 5. Verify functionality.
🔧 Temporary Workarounds
Disable password reset for admin accounts
allRemove or restrict access to password reset functionality for administrator accounts
Use external authentication
allImplement external authentication system that bypasses Piwigo's password reset mechanism
🧯 If You Can't Patch
- Restrict access to password reset functionality using web server rules or firewall
- Implement rate limiting on password reset requests to reduce brute force effectiveness
🔍 How to Verify
Check if Vulnerable:
Check Piwigo version in admin panel or by examining piwigo/include/constants.php file for version numberCheck Version:
grep 'PHPWG_VERSION' piwigo/include/constants.phpVerify Fix Applied:
Verify version is 2.8.1 or later and check that password reset tokens are generated using cryptographically secure methods📡 Detection & Monitoring
Log Indicators:
- Multiple password reset requests for administrator accounts
- Unusual password reset success events
Network Indicators:
- Unusual patterns of password reset requests to /password.php or similar endpoints
SIEM Query:
source="web_logs" AND (url="*password*" OR url="*lost*password*") AND user="admin" AND count > threshold🔗 References
- http://piwigo.org/release-2.8.1%2C
- https://github.com/Piwigo/Piwigo/commit/f51ee90c66527fd7ff634f3e8d414cb670da068d
- https://github.com/Piwigo/Piwigo/issues/470%2C
- http://piwigo.org/release-2.8.1%2C
- https://github.com/Piwigo/Piwigo/commit/f51ee90c66527fd7ff634f3e8d414cb670da068d
- https://github.com/Piwigo/Piwigo/issues/470%2C
