CVE-2022-31501
📋 TL;DR
This vulnerability allows attackers to perform absolute path traversal attacks in OnyxForum, enabling unauthorized file access on the server. It affects all deployments using vulnerable versions of the ChaoticOnyx/OnyxForum repository before the May 4, 2022 fix. The flaw exists in how Flask's send_file function is implemented without proper path validation.
💻 Affected Systems
- ChaoticOnyx/OnyxForum
📦 What is this software?
Onyxforum by Onyxforum Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through arbitrary file read, potentially leading to sensitive data exposure, credential theft, and further privilege escalation.
Likely Case
Unauthorized access to sensitive files including configuration files, source code, and potentially user data stored on the server filesystem.
If Mitigated
Limited impact with proper file system permissions and network segmentation, though some information disclosure may still occur.
🎯 Exploit Status
Path traversal vulnerabilities are well-understood and easy to exploit. The GitHub security advisory includes technical details that could be used to create exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit f25543dfc62a9694d7e4f67eebfa45e3de916053 and later
Vendor Advisory: https://github.com/ChaoticOnyx/OnyxForum/commit/f25543dfc62a9694d7e4f67eebfa45e3de916053
Restart Required: Yes
Instructions:
1. Update to the latest OnyxForum version after May 4, 2022. 2. Apply commit f25543dfc62a9694d7e4f67eebfa45e3de916053. 3. Restart the Flask application server. 4. Verify the fix by testing path traversal attempts.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allImplement WAF rules to block path traversal patterns in HTTP requests
File System Permissions Restriction
linuxRun the application with minimal file system permissions and restrict access to sensitive directories
chmod -R 750 /path/to/onyxforum
chown -R www-data:www-data /path/to/onyxforum
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the vulnerable server
- Deploy a reverse proxy with request filtering to block path traversal patterns
🔍 How to Verify
Check if Vulnerable:
Check if your OnyxForum version predates commit f25543dfc62a9694d7e4f67eebfa45e3de916053 (May 4, 2022). Test by attempting to access files outside the intended directory using ../ patterns.Check Version:
git log --oneline -1Verify Fix Applied:
Attempt path traversal attacks after patching; they should be blocked or return appropriate error messages. Verify the commit hash includes f25543dfc62a9694d7e4f67eebfa45e3de916053.📡 Detection & Monitoring
Log Indicators:
- Multiple 400/403 errors for requests containing ../ patterns
- Unusual file access patterns in application logs
- Requests for known sensitive files (e.g., /etc/passwd, .env files)
Network Indicators:
- HTTP requests with excessive ../ sequences
- Requests for files outside expected web directories
SIEM Query:
source="web_server_logs" AND (uri="*../*" OR uri="*/etc/passwd*" OR uri="*/.env*")🔗 References
- https://github.com/ChaoticOnyx/OnyxForum/commit/f25543dfc62a9694d7e4f67eebfa45e3de916053
- https://github.com/github/securitylab/issues/669#issuecomment-1117265726
- https://github.com/ChaoticOnyx/OnyxForum/commit/f25543dfc62a9694d7e4f67eebfa45e3de916053
- https://github.com/github/securitylab/issues/669#issuecomment-1117265726
