CVE-2022-31549
📋 TL;DR
This vulnerability allows attackers to read arbitrary files on the server through absolute path traversal in the olmax99/helm-flask-celery repository. It affects users running vulnerable versions of this Flask-based application before May 25, 2022. The unsafe use of Flask's send_file function enables directory traversal attacks.
💻 Affected Systems
- olmax99/helm-flask-celery repository
📦 What is this software?
Helm Flask Celery by Helm Flask Celery Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through reading sensitive files like SSH keys, configuration files, or database credentials, potentially leading to remote code execution.
Likely Case
Unauthorized access to sensitive server files including application source code, configuration files, and system files containing credentials.
If Mitigated
Limited impact with proper file system permissions and network segmentation preventing access to critical system files.
🎯 Exploit Status
Path traversal vulnerabilities are well-understood and easily exploitable with simple HTTP requests.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit 28c985d712d7ac26893433e8035e2e3678fcae9f
Vendor Advisory: https://github.com/olmax99/helm-flask-celery/commit/28c985d712d7ac26893433e8035e2e3678fcae9f
Restart Required: Yes
Instructions:
1. Update to the patched version from GitHub. 2. Replace unsafe send_file usage with secure alternatives. 3. Restart the Flask application. 4. Verify the fix by testing path traversal attempts.
🔧 Temporary Workarounds
Input Validation Workaround
allImplement strict input validation to reject path traversal sequences
# In Flask route handler, add validation:
import os
from flask import abort
# Validate file path before send_file
requested_path = request.args.get('file')
if '..' in requested_path or requested_path.startswith('/'):
abort(400, 'Invalid file path')
Web Application Firewall
linuxDeploy WAF rules to block path traversal patterns
# Example ModSecurity rule:
SecRule ARGS "@contains .." "id:1001,phase:2,deny,msg:'Path Traversal Attempt'"
# Example nginx rule:
location ~* \.\. { deny all; }
🧯 If You Can't Patch
- Implement strict file system permissions to limit accessible directories
- Deploy network segmentation to isolate vulnerable application from sensitive systems
🔍 How to Verify
Check if Vulnerable:
Test if the application allows accessing files with '../' sequences or absolute paths in file parametersCheck Version:
git log --oneline -1 # Check last commit hash matches patched versionVerify Fix Applied:
Attempt path traversal attacks after patching; they should return 400/403 errors instead of file contents📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing '../' sequences
- Multiple 403/400 errors from file access attempts
- Unusual file access patterns in application logs
Network Indicators:
- HTTP requests with path traversal payloads in parameters
- Abnormal file download patterns
SIEM Query:
source="web_logs" AND (uri="*..*" OR params="*..*")🔗 References
- https://github.com/github/securitylab/issues/669#issuecomment-1117265726
- https://github.com/olmax99/helm-flask-celery/commit/28c985d712d7ac26893433e8035e2e3678fcae9f
- https://github.com/github/securitylab/issues/669#issuecomment-1117265726
- https://github.com/olmax99/helm-flask-celery/commit/28c985d712d7ac26893433e8035e2e3678fcae9f
