CVE-2023-43500
📋 TL;DR
This CSRF vulnerability in Jenkins Build Failure Analyzer Plugin allows attackers to trick authenticated users into making unauthorized connections to attacker-controlled servers with specified credentials. It affects Jenkins instances with the vulnerable plugin installed, potentially exposing sensitive data or enabling further attacks.
💻 Affected Systems
- Jenkins Build Failure Analyzer Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could exfiltrate Jenkins credentials, access internal systems, or pivot to other network resources using stolen authentication.
Likely Case
Credential theft leading to unauthorized access to Jenkins or connected systems, potentially disrupting CI/CD pipelines.
If Mitigated
Limited impact with proper CSRF protections, network segmentation, and credential management in place.
🎯 Exploit Status
Exploitation requires tricking an authenticated user into visiting a malicious webpage; no authentication bypass needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.4.2 or later
Vendor Advisory: https://www.jenkins.io/security/advisory/2023-09-20/#SECURITY-3226
Restart Required: Yes
Instructions:
1. Update Jenkins Build Failure Analyzer Plugin to version 2.4.2 or later via Jenkins Plugin Manager. 2. Restart Jenkins to apply changes.
🔧 Temporary Workarounds
Enable CSRF Protection
allEnsure Jenkins global security settings have CSRF protection enabled (default in recent versions).
Check Jenkins > Manage Jenkins > Configure Global Security > Enable CSRF Protection
Disable Plugin Temporarily
allTemporarily disable the Build Failure Analyzer Plugin if immediate patching isn't possible.
Jenkins > Manage Jenkins > Manage Plugins > Installed > Build Failure Analyzer > Disable
🧯 If You Can't Patch
- Implement network segmentation to restrict Jenkins server outbound connections.
- Use web application firewalls (WAF) with CSRF protection rules.
🔍 How to Verify
Check if Vulnerable:
Check plugin version in Jenkins: Manage Jenkins > Manage Plugins > Installed > Build Failure Analyzer.Check Version:
In Jenkins web UI or via CLI: java -jar jenkins-cli.jar -s http://jenkins-url/ list-plugins | grep 'Build Failure Analyzer'Verify Fix Applied:
Verify plugin version is 2.4.2 or higher after update.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound connections from Jenkins to unknown IPs/ports
- Failed authentication attempts from Jenkins to external services
Network Indicators:
- Jenkins server making unexpected TCP connections to external hosts on non-standard ports
SIEM Query:
source="jenkins.log" AND ("connection failed" OR "authentication failed") AND dest_ip NOT IN internal_subnets