CVE-2022-31531
📋 TL;DR
This vulnerability allows attackers to read arbitrary files on the server through absolute path traversal in the dainst/cilantro repository. It affects users running vulnerable versions of this software, particularly those exposing it to untrusted networks. The flaw exists because Flask's send_file function is used without proper path validation.
💻 Affected Systems
- dainst/cilantro
📦 What is this software?
Cilantro by Dainst
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through reading sensitive files like /etc/passwd, SSH keys, configuration files, or database credentials, potentially leading to full system takeover.
Likely Case
Unauthorized access to sensitive server files containing credentials, configuration data, or user information, enabling further attacks.
If Mitigated
Limited impact if proper network segmentation, file permissions, and input validation are in place, though the vulnerability still exists.
🎯 Exploit Status
Path traversal vulnerabilities are easily exploitable with simple HTTP requests. Public GitHub issues demonstrate the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 0.0.4
Vendor Advisory: https://github.com/dainst/cilantro/security/advisories
Restart Required: Yes
Instructions:
1. Update to the latest version of dainst/cilantro. 2. Verify the fix implements proper path validation. 3. Restart the application service.
🔧 Temporary Workarounds
Input Validation Middleware
allAdd middleware to validate and sanitize file paths before they reach send_file function
Implement custom Flask middleware that checks for path traversal patterns like '../', '..\\', absolute paths
Web Application Firewall Rules
allConfigure WAF to block path traversal patterns in requests
Add WAF rules to detect and block patterns like '/etc/', '/proc/', '../', absolute paths
🧯 If You Can't Patch
- Implement strict file system permissions to limit what files the application user can access
- Deploy behind reverse proxy with strict URL filtering and input validation
🔍 How to Verify
Check if Vulnerable:
Check if running cilantro version 0.0.4 or earlier and if the application uses Flask's send_file without proper path validationCheck Version:
pip show cilantro | grep VersionVerify Fix Applied:
Test that path traversal attempts (e.g., requests for '/etc/passwd' or '../../etc/passwd') are properly blocked📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing path traversal patterns like '../', '..\\', '/etc/', absolute paths
- Failed file access attempts to sensitive system paths
Network Indicators:
- HTTP requests with unusual file paths or directory traversal sequences
- Responses containing sensitive file contents
SIEM Query:
source="web_logs" AND (uri="*../*" OR uri="*/etc/*" OR uri="*/proc/*" OR uri="*/root/*")