CVE-2022-44571
📋 TL;DR
CVE-2022-44571 is a denial of service vulnerability in Rack's Content-Disposition header parser that allows attackers to craft malicious inputs causing excessive processing time. This affects virtually all Ruby on Rails applications that parse multipart posts using Rack, potentially leading to service disruption.
💻 Affected Systems
- Rack
- Ruby on Rails
- Applications using Rack for multipart parsing
📦 What is this software?
Rack by Rack
Rack by Rack
Rack by Rack
Rack by Rack
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to resource exhaustion from crafted malicious requests overwhelming the parser.
Likely Case
Degraded application performance and intermittent service disruptions from targeted DoS attacks.
If Mitigated
Minimal impact with proper rate limiting, request validation, and updated Rack versions.
🎯 Exploit Status
Exploitation requires crafting malicious Content-Disposition headers but doesn't require authentication or complex techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Rack 2.0.9.2, 2.1.4.2, 2.2.4.1, or 3.0.0.1
Vendor Advisory: https://discuss.rubyonrails.org/t/cve-2022-44571-possible-denial-of-service-vulnerability-in-rack-content-disposition-parsing/82126
Restart Required: Yes
Instructions:
1. Update Gemfile to specify patched Rack version. 2. Run 'bundle update rack'. 3. Restart application server. 4. Verify update with 'bundle show rack'.
🔧 Temporary Workarounds
Rate Limiting
allImplement request rate limiting to prevent DoS attacks
# Use Rack::Attack or similar middleware
# Configure maximum requests per IP/time period
Request Validation
allFilter or reject requests with suspicious Content-Disposition headers
# Add middleware to inspect and reject malformed headers
# Example: reject requests with Content-Disposition headers exceeding length limits
🧯 If You Can't Patch
- Implement Web Application Firewall (WAF) rules to block requests with malformed Content-Disposition headers
- Deploy reverse proxy with request filtering and rate limiting capabilities
🔍 How to Verify
Check if Vulnerable:
Check Rack version with 'bundle show rack' or 'gem list rack' and compare against vulnerable versions.Check Version:
bundle show rack | grep rackVerify Fix Applied:
Confirm Rack version is 2.0.9.2, 2.1.4.2, 2.2.4.1, or 3.0.0.1 using 'bundle show rack'.📡 Detection & Monitoring
Log Indicators:
- Multiple requests with similar Content-Disposition headers
- Increased response times for multipart requests
- Application server resource exhaustion alerts
Network Indicators:
- Unusual patterns of multipart POST requests
- Requests with abnormally long Content-Disposition headers
SIEM Query:
source="application.log" AND "Content-Disposition" AND (response_time>5000 OR status=500)🔗 References
- https://discuss.rubyonrails.org/t/cve-2022-44571-possible-denial-of-service-vulnerability-in-rack-content-disposition-parsing/82126
- https://security.netapp.com/advisory/ntap-20231208-0013/
- https://www.debian.org/security/2023/dsa-5530
- https://discuss.rubyonrails.org/t/cve-2022-44571-possible-denial-of-service-vulnerability-in-rack-content-disposition-parsing/82126
- https://security.netapp.com/advisory/ntap-20231208-0013/
- https://www.debian.org/security/2023/dsa-5530
