CVE-2025-53678
📋 TL;DR
The Jenkins User1st uTester Plugin 1.1 and earlier stores JWT tokens unencrypted in global configuration files on the Jenkins controller. This allows attackers with file system access to steal authentication tokens and potentially impersonate users or access sensitive systems. Organizations using vulnerable plugin versions are affected.
💻 Affected Systems
- Jenkins User1st uTester Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access to Jenkins, compromise connected systems, and exfiltrate sensitive data or deploy ransomware across the CI/CD pipeline.
Likely Case
Unauthorized users with file system access steal JWT tokens to impersonate legitimate users, access restricted Jenkins resources, or manipulate build processes.
If Mitigated
Limited to users with legitimate file system access who might misuse tokens, with minimal impact if proper access controls and monitoring are implemented.
🎯 Exploit Status
Exploitation requires file system access to the Jenkins controller, which typically means authenticated access or other vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2 or later
Vendor Advisory: https://www.jenkins.io/security/advisory/2025-07-09/#SECURITY-3518
Restart Required: Yes
Instructions:
1. Update Jenkins to latest version. 2. Navigate to Manage Jenkins > Plugin Manager. 3. Update uTester plugin to version 1.2 or later. 4. Restart Jenkins service.
🔧 Temporary Workarounds
Remove or disable uTester plugin
allTemporarily disable or uninstall the vulnerable plugin if immediate patching is not possible.
Navigate to Manage Jenkins > Plugin Manager, select uTester plugin, click Uninstall or Disable
Restrict file system access
linuxLimit access to Jenkins controller file system to authorized administrators only.
chmod 600 /var/lib/jenkins/config.xml
chown jenkins:jenkins /var/lib/jenkins/
🧯 If You Can't Patch
- Implement strict access controls to Jenkins controller file system
- Monitor for unauthorized access to configuration files and review audit logs regularly
🔍 How to Verify
Check if Vulnerable:
Check Jenkins plugin manager for uTester plugin version 1.1 or earlier.Check Version:
grep 'uTester' /var/lib/jenkins/plugins/uTester/META-INF/MANIFEST.MF | grep 'Plugin-Version'Verify Fix Applied:
Confirm uTester plugin version is 1.2 or later in plugin manager.📡 Detection & Monitoring
Log Indicators:
- Unauthorized access to Jenkins configuration files
- Failed authentication attempts followed by successful token-based access
Network Indicators:
- Unusual API calls using JWT tokens from unexpected IP addresses
SIEM Query:
source="jenkins.log" AND ("config.xml access" OR "uTester token")