CVE-2023-27905
📋 TL;DR
This stored XSS vulnerability in Jenkins update-center2 allows attackers who can provide plugins for hosting to inject malicious scripts into plugin download pages. When users view these pages, the scripts execute in their browsers, potentially compromising their sessions or systems. All Jenkins instances using update-center2 versions 3.13 or 3.14 are affected.
💻 Affected Systems
- Jenkins update-center2
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, hijack Jenkins sessions, install backdoors, or pivot to internal systems through compromised Jenkins instances.
Likely Case
Session hijacking, credential theft, or unauthorized actions performed through compromised administrator accounts.
If Mitigated
Limited impact if proper content security policies and input validation are in place, though the vulnerability still exists.
🎯 Exploit Status
Exploitation requires the ability to provide plugins for hosting. Once a malicious plugin is hosted, the XSS triggers automatically when users view the plugin download page.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: update-center2 3.15 or later
Vendor Advisory: https://www.jenkins.io/security/advisory/2023-03-08/#SECURITY-3063
Restart Required: Yes
Instructions:
1. Update Jenkins update-center2 to version 3.15 or later. 2. Restart the Jenkins service. 3. Verify the update was successful by checking the version.
🔧 Temporary Workarounds
Content Security Policy
allImplement a strict Content Security Policy to prevent script execution from untrusted sources.
Plugin Source Restriction
allRestrict plugin sources to trusted repositories only and disable untrusted plugin hosting.
🧯 If You Can't Patch
- Restrict plugin uploads to trusted administrators only
- Implement network segmentation to isolate Jenkins from critical systems
🔍 How to Verify
Check if Vulnerable:
Check the update-center2 version in Jenkins. If it's 3.13 or 3.14, the system is vulnerable.Check Version:
Check Jenkins update-center2 version through Jenkins interface or configuration files.Verify Fix Applied:
Verify that update-center2 version is 3.15 or higher after applying the patch.📡 Detection & Monitoring
Log Indicators:
- Unusual plugin uploads from untrusted sources
- Suspicious JavaScript execution in plugin pages
Network Indicators:
- Unexpected outbound connections from Jenkins to external domains
SIEM Query:
Search for plugin upload events followed by unusual web requests from Jenkins instances.