CVE-2021-21642 : Vulnerability Insights and Analysis

Jenkins Config File Provider Plugin version 3.7.0 and earlier are vulnerable to XML external entity (XXE) attacks due to a misconfiguration in the XML parser.

Understanding CVE-2021-21642

This vulnerability affects Jenkins Config File Provider Plugin versions 3.7.0 and below, exposing them to XXE attacks.

What is CVE-2021-21642?

CVE-2021-21642 is a vulnerability in Jenkins Config File Provider Plugin versions 3.7.0 and earlier that allows attackers to launch XML external entity (XXE) attacks.

The Impact of CVE-2021-21642

The vulnerability can be exploited by malicious actors to read arbitrary files on the Jenkins server, leading to unauthorized access to sensitive information.

Technical Details of CVE-2021-21642

Jenkins Config File Provider Plugin 3.7.0 and earlier versions lack proper configuration to protect against XXE attacks.

Vulnerability Description

The vulnerability arises from the improper handling of XML external entities, enabling attackers to access unauthorized data on the server.

Affected Systems and Versions

Product: Jenkins Config File Provider Plugin
Vendor: Jenkins project
Versions Affected: <= 3.7.0 (custom versions)

Exploitation Mechanism

Attackers can exploit the misconfigured XML parser in Jenkins Config File Provider Plugin to include external entities and retrieve sensitive files.

Mitigation and Prevention

It is crucial to take immediate steps to secure Jenkins instances using the affected versions and implement long-term security practices.

Immediate Steps to Take

Update Jenkins Config File Provider Plugin to a version higher than 3.7.0 that addresses the XXE vulnerability.
Monitor server logs for any suspicious activity indicative of XXE attacks.

Long-Term Security Practices

Regularly update Jenkins and its plugins to patch known vulnerabilities.
Implement proper input validation and secure coding practices to prevent XXE vulnerabilities.

Patching and Updates

Jenkins project has released patches to address the XXE vulnerability in the Config File Provider Plugin. It is essential to apply these updates promptly to mitigate the risk of exploitation.