CVE-2021-21604 : Exploit Details and Defense Strategies

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows attackers with permission to create or configure various objects to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects once discarded by an administrator.

Understanding CVE-2021-21604

This section provides a detailed overview of CVE-2021-21604.

What is CVE-2021-21604?

CVE-2021-21604 is a vulnerability in Jenkins versions 2.274 and earlier, LTS 2.263.1 and earlier that enables attackers to inject crafted content into Old Data Monitor, potentially leading to the instantiation of unsafe objects.

The Impact of CVE-2021-21604

This vulnerability allows an attacker with certain permissions to manipulate objects within Jenkins, posing a risk of executing malicious code and compromising the integrity of the system.

Technical Details of CVE-2021-21604

This section delves into the technical aspects of CVE-2021-21604.

Vulnerability Description

The vulnerability arises from the improper handling of user-supplied data within the Old Data Monitor component of Jenkins, facilitating injection attacks and subsequent execution of unauthorized actions.

Affected Systems and Versions

Jenkins versions 2.274 and earlier, as well as LTS 2.263.1 and earlier, are impacted by this vulnerability, potentially affecting systems that have not applied relevant patches.

Exploitation Mechanism

Attackers with specific permissions can exploit this vulnerability by manipulating objects to insert malicious content into the Old Data Monitor, leading to the instantiation of dangerous objects after being discarded.

Mitigation and Prevention

This section outlines the steps to mitigate and prevent exploitation of CVE-2021-21604.

Immediate Steps to Take

Administrators are advised to update Jenkins to a patched version and review user permissions to limit access to vulnerable components.

Long-Term Security Practices

Regular security audits, employee training on secure coding practices, and monitoring for suspicious activities can enhance overall system security.

Patching and Updates

Keeping Jenkins up to date with the latest security patches and following vendor advisories is crucial to prevent exploitation of known vulnerabilities.