CVE-2021-21647 : Vulnerability Insights and Analysis

Jenkins CloudBees CD Plugin 1.1.21 and earlier versions are impacted by a vulnerability that allows attackers with Item/Read permission to schedule project builds without needing Item/Build permission.

Understanding CVE-2021-21647

This CVE record details a vulnerability in Jenkins CloudBees CD Plugin versions 1.1.21 and below, affecting the permission check on an HTTP endpoint.

What is CVE-2021-21647?

The CVE-2021-21647 vulnerability in Jenkins CloudBees CD Plugin allows users with Item/Read permission to schedule project builds without requiring Item/Build permission, potentially leading to unauthorized actions by attackers.

The Impact of CVE-2021-21647

The impact of this vulnerability is significant as it enables unauthorized users to bypass certain permission checks and initiate project builds, potentially causing disruption or unauthorized access within Jenkins instances.

Technical Details of CVE-2021-21647

This section provides technical insights into the vulnerability.

Vulnerability Description

Jenkins CloudBees CD Plugin 1.1.21 and earlier versions lack a permission check in an HTTP endpoint, allowing users with Item/Read permission to schedule project builds without Item/Build permission.

Affected Systems and Versions

The vulnerable versions of Jenkins CloudBees CD Plugin include 1.1.21 and earlier releases, while version 1.1.18.1 is unaffected by this issue.

Exploitation Mechanism

Attackers with Item/Read permission can exploit this vulnerability by leveraging the inadequate permission verification in the HTTP endpoint to trigger unauthorized project builds.

Mitigation and Prevention

Protecting systems from CVE-2021-21647 requires immediate action and long-term security measures.

Immediate Steps to Take

Users are advised to upgrade Jenkins CloudBees CD Plugin to versions beyond 1.1.21 to prevent unauthorized scheduling of project builds. Additionally, review and adjust permission settings to ensure proper access controls.

Long-Term Security Practices

Implement a robust permission model and regularly review access rights to mitigate similar vulnerabilities in the future. Continuous security monitoring and updates are crucial for maintaining system integrity.

Patching and Updates

Stay informed about security advisories and apply patches promptly to address known vulnerabilities and protect Jenkins instances.