CVE-2020-14326
📋 TL;DR
CVE-2020-14326 is a denial-of-service vulnerability in RESTEasy's RootNode caching mechanism that allows attackers to cause hash flooding, resulting in slower request processing and increased CPU usage. This affects applications using vulnerable versions of RESTEasy for RESTful web services. The vulnerability can be exploited without authentication to degrade service performance.
💻 Affected Systems
- RESTEasy
📦 What is this software?
Resteasy by Redhat
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to CPU exhaustion and request processing slowdown, affecting all users of the vulnerable application.
Likely Case
Degraded application performance with increased response times and higher server resource consumption, potentially causing partial service disruption.
If Mitigated
Minimal impact with proper rate limiting, monitoring, and updated versions, though some performance degradation may still occur during attack attempts.
🎯 Exploit Status
Exploitation requires sending specially crafted HTTP requests to trigger hash collisions. No authentication is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: RESTEasy 3.15.2 and later
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=1855826
Restart Required: Yes
Instructions:
1. Identify RESTEasy version in your application. 2. Update to RESTEasy 3.15.2 or later. 3. Rebuild and redeploy your application. 4. Restart the application server.
🔧 Temporary Workarounds
Rate Limiting
allImplement request rate limiting to reduce impact of hash flooding attacks
Configure rate limiting in your web server or application firewall
Request Filtering
allFilter or block suspicious request patterns that could trigger hash collisions
Implement custom request filters in your application
🧯 If You Can't Patch
- Implement strict rate limiting and monitoring for abnormal request patterns
- Deploy web application firewall with DoS protection rules
🔍 How to Verify
Check if Vulnerable:
Check RESTEasy version in your application dependencies or classpath. If version is between 3.0.0 and 3.15.1 inclusive, you are vulnerable.Check Version:
Check Maven/Gradle dependencies or examine RESTEasy JAR file versionVerify Fix Applied:
Verify RESTEasy version is 3.15.2 or later after update. Test application functionality and monitor for performance issues.📡 Detection & Monitoring
Log Indicators:
- Unusually high CPU usage
- Increased request processing times
- Multiple similar requests from single sources
Network Indicators:
- High volume of similar HTTP requests
- Requests causing hash collisions
SIEM Query:
source="application_logs" AND (message="high cpu" OR message="slow request") AND resource="RESTEasy"