CVE-2021-21615 : What You Need to Know

This CVE pertains to a vulnerability in Jenkins versions 2.275 and LTS 2.263.2 that allows an attacker to read arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Understanding CVE-2021-21615

This section will delve into the details of the CVE-2021-21615 vulnerability.

What is CVE-2021-21615?

CVE-2021-21615 is a security flaw found in Jenkins versions 2.275 and LTS 2.263.2, enabling unauthorized access to arbitrary files via the file browser for workspaces and archived artifacts.

The Impact of CVE-2021-21615

The exploit could result in sensitive data exposure and unauthorized access to files, potentially leading to further system compromise.

Technical Details of CVE-2021-21615

Below are the technical specifics regarding the CVE-2021-21615 vulnerability.

Vulnerability Description

The vulnerability in Jenkins versions 2.275 and LTS 2.263.2 allows attackers to read arbitrary files by exploiting a race condition between the time of checking file existence and the time of using the file.

Affected Systems and Versions

Jenkins versions 2.275 and LTS 2.263.2 are impacted by this vulnerability, while other versions are not affected.

Exploitation Mechanism

By exploiting the time-of-check to time-of-use race condition, malicious actors can gain unauthorized access to sensitive files within Jenkins.

Mitigation and Prevention

In this section, we outline steps to mitigate and prevent potential exploitation of the CVE-2021-21615 vulnerability.

Immediate Steps to Take

Upgrade Jenkins to a non-vulnerable version immediately.
Implement access controls to restrict file browsing capabilities.
Monitor file access and usage for any suspicious activities.

Long-Term Security Practices

Regularly update Jenkins and all plugins to the latest versions.
Conduct security audits and assessments periodically to identify and address vulnerabilities.
Educate users on secure file handling practices within Jenkins.

Patching and Updates

Stay informed about security advisories from Jenkins and promptly apply patches and updates to ensure your system is protected against known vulnerabilities.