CVE-2021-21623 : Security Advisory and Response

A vulnerability has been identified in Jenkins Matrix Authorization Strategy Plugin that affects versions up to 2.6.5. Attackers with Item/Read permission on nested items can access them, bypassing the required permissions for parent folders.

Understanding CVE-2021-21623

This CVE refers to an incorrect permission check issue in Jenkins Matrix Authorization Strategy Plugin that can be exploited by attackers to gain unauthorized access.

What is CVE-2021-21623?

CVE-2021-21623 is a security vulnerability in Jenkins Matrix Authorization Strategy Plugin versions prior to 2.6.5, allowing attackers to access nested items without the necessary permissions.

The Impact of CVE-2021-21623

The vulnerability enables users with limited permissions to bypass access controls and view confidential information stored in Jenkins instances, potentially leading to unauthorized data exposure.

Technical Details of CVE-2021-21623

This section provides an overview of the vulnerability's technical aspects.

Vulnerability Description

The vulnerability arises from an incorrect permission validation mechanism in Jenkins Matrix Authorization Strategy Plugin up to version 2.6.5, letting unauthorized users view nested items.

Affected Systems and Versions

Systems using Jenkins Matrix Authorization Strategy Plugin versions less than or equal to 2.6.5 are vulnerable to this security issue.

Exploitation Mechanism

Attackers with Item/Read permission on nested items can leverage this vulnerability to access restricted content without the required permissions.

Mitigation and Prevention

Below are the steps to mitigate and prevent potential exploitation of CVE-2021-21623.

Immediate Steps to Take

Upgrade Jenkins Matrix Authorization Strategy Plugin to version 2.6.6 or newer to patch the vulnerability.
Restrict access permissions to minimize the impact of unauthorized access.

Long-Term Security Practices

Regularly monitor and update Jenkins plugins to ensure security patches are applied promptly.
Educate users on proper permission management to prevent similar incidents in the future.

Patching and Updates

Stay informed about security advisories from Jenkins project and promptly apply recommended patches to secure Jenkins instances from potential exploits.