CVE-2022-21831
📋 TL;DR
This is a critical code injection vulnerability in Ruby on Rails Active Storage that allows attackers to execute arbitrary code by manipulating image_processing arguments. It affects all applications using Active Storage v5.2.0 and later. Attackers can achieve remote code execution on vulnerable systems.
💻 Affected Systems
- Ruby on Rails Active Storage
📦 What is this software?
Active Storage by Rubyonrails
Active Storage by Rubyonrails
Active Storage by Rubyonrails
Active Storage by Rubyonrails
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the server, allowing data theft, lateral movement, and persistent access.
Likely Case
Remote code execution leading to application compromise, data exfiltration, and potential deployment of malware or ransomware.
If Mitigated
Limited impact with proper input validation and security controls, potentially resulting in denial of service or limited data exposure.
🎯 Exploit Status
Exploitation requires the ability to upload or process images through Active Storage. Public proof-of-concept code exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Rails 7.0.2.4, 6.1.4.6, 6.0.4.8, or upgrade to Active Storage gem v7.0.2.4, v6.1.6.1, v6.0.6.1
Vendor Advisory: https://github.com/advisories/GHSA-w749-p3v6-hccq
Restart Required: Yes
Instructions:
1. Update Rails gem to patched version. 2. Run 'bundle update rails' or 'bundle update activestorage'. 3. Restart application server. 4. Verify update with 'bundle show rails'.
🔧 Temporary Workarounds
Disable Active Storage image processing
allTemporarily disable Active Storage's image processing functionality if not essential
# In config/application.rb or environment config
# config.active_storage.variant_processor = nil
Input validation for image parameters
allImplement strict validation for image_processing parameters before passing to Active Storage
# In controller actions processing images
# Validate and sanitize all image processing parameters
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all image processing parameters
- Deploy web application firewall (WAF) rules to block suspicious image processing requests
🔍 How to Verify
Check if Vulnerable:
Check Rails version with 'rails --version' or check Gemfile.lock for Active Storage version >=5.2.0Check Version:
rails --versionVerify Fix Applied:
Verify Rails version is 7.0.2.4+, 6.1.4.6+, or 6.0.4.8+. Check Gemfile.lock shows patched Active Storage version.📡 Detection & Monitoring
Log Indicators:
- Unusual image processing requests with suspicious parameters
- Errors in Active Storage logs related to image processing
Network Indicators:
- HTTP POST requests to Active Storage endpoints with unusual image parameters
- Requests containing shell commands in image processing parameters
SIEM Query:
source="rails.log" AND "ActiveStorage" AND ("image_processing" OR "variant") AND ("error" OR "exception")🔗 References
- https://github.com/advisories/GHSA-w749-p3v6-hccq
- https://lists.debian.org/debian-lts-announce/2022/09/msg00002.html
- https://security.netapp.com/advisory/ntap-20221118-0001/
- https://www.debian.org/security/2023/dsa-5372
- https://github.com/advisories/GHSA-w749-p3v6-hccq
- https://lists.debian.org/debian-lts-announce/2022/09/msg00002.html
- https://security.netapp.com/advisory/ntap-20221118-0001/
- https://www.debian.org/security/2023/dsa-5372
