The Jenkins AnchorChain Plugin 1.0 is vulnerable to a stored Cross-Site Scripting (XSS) attack due to its failure to restrict URL schemes for links generated from workspace content. Specifically, the plugin allows the use of the `javascript:` scheme, which enables attackers to inject malicious scripts. This vulnerability is exploitable when an attacker can control the input file used in the Anchor Chain post-build step. The injected script executes in the context of the user’s browser, potentially leading to unauthorized actions, data theft, or session hijacking. As of the advisory publication date, no patch or fix is available, leaving systems exposed to this high-severity vulnerability.
DailyCVE Form:
Platform: Jenkins
Version: AnchorChain Plugin 1.0
Vulnerability: Stored XSS
Severity: High
Date: Mar 19, 2025
What Undercode Say:
Exploitation:
1. Exploit Code Example:
<a href="javascript:alert('XSS')">Click Me</a>
Attackers can embed such scripts in files processed by the AnchorChain Plugin.
2. Payload Delivery:
- Upload a malicious file to the Jenkins workspace.
- Ensure the file contains a `javascript:` URL scheme.
- Trigger the AnchorChain post-build step to process the file.
3. Impact:
- Steal session cookies:
document.cookie. - Redirect users:
window.location='http://evil.com'. - Perform unauthorized actions on behalf of the user.
Protection:
1. Mitigation:
- Disable the AnchorChain Plugin until a patch is available.
- Sanitize all user-controlled input to remove `javascript:` schemes.
2. Input Sanitization Code:
import re
def sanitize_url(url):
if re.match(r'javascript:', url, re.IGNORECASE):
raise ValueError("Invalid URL scheme")
return url
3. Web Application Firewall (WAF):
- Configure WAF rules to block requests containing `javascript:` URLs.
4. Jenkins Configuration:
- Restrict plugin usage to trusted users only.
- Monitor logs for suspicious activity.
5. Patch Monitoring:
- Regularly check for updates from the Jenkins security advisory page.
6. Exploit Detection:
- Use the following command to search for malicious scripts in logs:
grep -i "javascript:" /var/log/jenkins/jenkins.log
7. Browser Protection:
- Enable Content Security Policy (CSP) to block inline scripts:
Content-Security-Policy: script-src 'self';
8. Jenkins Script Console:
- Use the Jenkins Script Console to identify vulnerable plugins:
Jenkins.instance.pluginManager.plugins.each { plugin -> println("${plugin.shortName}: ${plugin.version}") }By following these steps, administrators can mitigate the risk posed by this vulnerability while awaiting an official fix.
References:
Reported By: https://github.com/advisories/GHSA-xxrg-mg63-qfpj
Extra Source Hub:
Undercode
