CVE-2022-40916
📋 TL;DR
CVE-2022-40916 is a session fixation vulnerability in Tiny File Manager v2.4.7 and below that allows attackers to hijack user sessions by fixing session IDs before authentication. This affects all users of vulnerable Tiny File Manager installations, particularly those exposed to the internet.
💻 Affected Systems
- Tiny File Manager
📦 What is this software?
Tiny File Manager by Prasathmani
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the file manager instance leading to unauthorized file access, modification, deletion, and potential privilege escalation to underlying system.
Likely Case
Unauthorized access to sensitive files, directory traversal, and potential data exfiltration from the file manager.
If Mitigated
Limited impact with proper network segmentation and access controls, though session security remains compromised.
🎯 Exploit Status
Public proof-of-concept demonstrates exploitation without authentication. Attack requires network access to vulnerable instance.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v2.4.8 and above
Vendor Advisory: https://github.com/prasathmani/tinyfilemanager
Restart Required: No
Instructions:
1. Backup current installation. 2. Download latest version from GitHub. 3. Replace vulnerable files with patched version. 4. Verify session regeneration occurs after authentication.
🔧 Temporary Workarounds
Session Regeneration Workaround
allManually implement session regeneration after successful authentication
Modify authentication logic to call session_regenerate_id(true) after successful login
Access Restriction
linuxRestrict access to Tiny File Manager via network controls
iptables -A INPUT -p tcp --dport [PORT] -s [TRUSTED_IP] -j ACCEPT
iptables -A INPUT -p tcp --dport [PORT] -j DROP
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted IPs only
- Monitor for suspicious session activity and implement additional authentication layers
🔍 How to Verify
Check if Vulnerable:
Check version in index.php or via web interface. If version is 2.4.7 or below, system is vulnerable.Check Version:
grep -i 'version' index.php | head -1Verify Fix Applied:
Test session fixation by attempting to set session ID before authentication and verify new session ID is generated after login.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts with same session ID
- Session IDs persisting across authentication events
- Unauthorized file access patterns
Network Indicators:
- HTTP requests with manipulated session cookies
- Traffic to Tiny File Manager from unexpected sources
SIEM Query:
source="web_logs" AND (uri="/tinyfilemanager*" OR user_agent="*TinyFileManager*") AND (session_id_changes=0 OR cookie_manipulation_detected=true)