CVE-2021-21619 : Exploit Details and Defense Strategies

Jenkins Claim Plugin version 2.18.1 and earlier are prone to a stored cross-site scripting (XSS) vulnerability. This flaw allows attackers to exploit the user display name without proper escaping, providing avenues for malicious activities.

Understanding CVE-2021-21619

This section delves into the impact, technical details, and mitigation strategies related to the CVE-2021-21619 vulnerability.

What is CVE-2021-21619?

The Jenkins Claim Plugin version 2.18.1 and earlier contain a vulnerability that does not properly escape user display names. This oversight opens up the plugin to stored cross-site scripting (XSS) attacks, leaving Jenkins instances at risk.

The Impact of CVE-2021-21619

The vulnerability in Jenkins Claim Plugin allows attackers to execute malicious scripts through specially crafted user display names. This could lead to unauthorized access, data theft, and various other security breaches in Jenkins environments.

Technical Details of CVE-2021-21619

Below are more technical specifics associated with the Jenkins Claim Plugin vulnerability.

Vulnerability Description

Jenkins Claim Plugin 2.18.1 and earlier versions lack proper user display name escaping, enabling stored cross-site scripting (XSS) attacks. Attackers with control over Jenkins user display names can exploit this flaw for malicious purposes.

Affected Systems and Versions

The affected version of the Jenkins Claim Plugin is 2.18.1 and earlier. Instances using these versions are at risk of the stored cross-site scripting (XSS) vulnerability.

Exploitation Mechanism

Malicious actors can take advantage of the vulnerability by manipulating user display names within Jenkins. By inserting specially crafted scripts, attackers can execute arbitrary code and compromise the integrity of Jenkins instances.

Mitigation and Prevention

To safeguard Jenkins environments from CVE-2021-21619, it is crucial to implement immediate mitigations along with long-term security practices.

Immediate Steps to Take

Immediately update the Jenkins Claim Plugin to a secure version that includes the necessary fixes for the XSS vulnerability. Monitor user activities and disable accounts with suspicious display names.

Long-Term Security Practices

Regularly perform security audits and code reviews to detect and address vulnerabilities proactively. Educate users on safe naming conventions and provide training on identifying and reporting suspicious activities.

Patching and Updates

Stay informed about security advisories from Jenkins and promptly apply patches and updates to ensure the latest security enhancements and fixes are in place.