CVE-2022-31547
📋 TL;DR
This vulnerability allows attackers to read arbitrary files on the server through absolute path traversal in the noamezekiel/sphere repository. It affects any system running this Flask-based application with vulnerable code. Attackers can access sensitive files like configuration files, passwords, or source code.
💻 Affected Systems
- noamezekiel/sphere repository
📦 What is this software?
Sphere by Sphere Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through reading sensitive files like SSH keys, database credentials, or configuration files leading to lateral movement and data exfiltration.
Likely Case
Unauthorized access to sensitive server files including application source code, configuration files, and potentially user data stored on the filesystem.
If Mitigated
Limited impact with proper file permissions and network segmentation, though sensitive files could still be exposed.
🎯 Exploit Status
The vulnerability is in a public GitHub repository with documented exploitation methods. Path traversal vulnerabilities are commonly exploited.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://github.com/github/securitylab/issues/669#issuecomment-1117265726
Restart Required: Yes
Instructions:
1. Review the GitHub security advisory
2. Manually fix the Flask send_file implementation
3. Add proper path validation and sanitization
4. Restart the application
🔧 Temporary Workarounds
Implement Path Validation
allAdd input validation to reject absolute paths and directory traversal sequences
# In Flask route handling:
# Replace unsafe: send_file(requested_path)
# With safe: send_file(os.path.join('safe_base_dir', sanitized_filename))
Web Application Firewall Rules
allConfigure WAF to block requests containing path traversal patterns
# Example mod_security rule:
SecRule REQUEST_URI "@contains ../" "id:1001,phase:1,deny,status:403"
🧯 If You Can't Patch
- Isolate the vulnerable application in a restricted network segment with no access to sensitive files
- Implement strict file system permissions to limit what files the application user can access
🔍 How to Verify
Check if Vulnerable:
Review Flask routes using send_file() function and check if user input is passed without proper path validationCheck Version:
Check repository commit history and date - vulnerable if using code from before 2020-05-31Verify Fix Applied:
Test that absolute paths and directory traversal sequences (../../) are properly rejected📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing absolute paths or ../ sequences
- Failed file access attempts outside expected directories
- Unusual file access patterns from single IPs
Network Indicators:
- HTTP requests with encoded path traversal sequences (%2e%2e%2f)
- Multiple failed file access attempts
SIEM Query:
source="web_logs" AND (uri="*../*" OR uri="*absolute/path*" OR status=403 AND uri="*/file*" )