CVE-2022-31515
📋 TL;DR
This vulnerability allows attackers to read arbitrary files on the server through absolute path traversal in the Delor4/CarceresBE repository. It affects any system running CarceresBE version 1.0 or earlier with the vulnerable Flask send_file implementation. Attackers can access sensitive files like configuration files, credentials, or system files.
💻 Affected Systems
- Delor4/CarceresBE
📦 What is this software?
Carceresbe by Carceresbe Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through reading sensitive files like SSH keys, database credentials, or configuration files containing secrets, potentially leading to lateral movement or data exfiltration.
Likely Case
Unauthorized access to sensitive application files, configuration data, or system files that could enable further attacks or data theft.
If Mitigated
Limited impact with proper file permissions and network segmentation, though sensitive data exposure remains possible.
🎯 Exploit Status
Path traversal vulnerabilities are commonly exploited and require minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 1.0
Vendor Advisory: https://github.com/github/securitylab/issues/669
Restart Required: Yes
Instructions:
1. Update to the latest version of CarceresBE repository. 2. Replace vulnerable send_file calls with safe implementations using proper path validation. 3. Restart the application service.
🔧 Temporary Workarounds
Implement Input Validation
allAdd server-side validation to reject absolute paths and path traversal sequences in file requests.
# Python example: validate user input before send_file
import os
from flask import abort
def safe_send_file(path):
if os.path.isabs(path) or '..' in path:
abort(403)
# Continue with safe file sending
Restrict File Access Permissions
linuxConfigure the application to run with minimal file system permissions and restrict access to sensitive directories.
# Run application with restricted user
sudo -u appuser python app.py
# Set proper directory permissions
chmod 750 /path/to/app/files
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block path traversal patterns in requests.
- Isolate the vulnerable system in a segmented network with strict outbound traffic controls.
🔍 How to Verify
Check if Vulnerable:
Test if the application allows accessing files using absolute paths or '../' sequences in file request parameters.Check Version:
Check the repository version or application configuration for CarceresBE version information.Verify Fix Applied:
Attempt path traversal attacks after patching; successful requests should return 403/404 errors instead of file contents.📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing '../', '..\\', or absolute paths in URL parameters
- Unusual file access patterns from single IP addresses
- 403/404 errors followed by successful file access attempts
Network Indicators:
- HTTP requests with path traversal patterns in query strings or POST data
- Rapid sequential requests for different file paths
SIEM Query:
source="web_logs" AND (url="*../*" OR url="*..\\*" OR url="*/etc/*" OR url="*/proc/*")