Sunset Decoy: VulnHub CTF walkthrough

In this article, we will solve a Capture the Flag (CTF) challenge that was posted on the VulnHub website by an author whitecr0wz. As per the description given by the author, this is an intermediate-level CTF. The target of this CTF is to get to the root of the machine and read the flag file.

You can check my previous articles for more CTF challenges. I have provided a downloadable URL for this CTF here.

You can download the machine and run it on VirtualBox. The torrent downloadable URL is also available for this VM and has been added in the reference section of this article.

For those who are not aware of the site, VulnHub is a well-known website for security researchers which aims to provide users with a way to learn and practice their hacking skills through a series of challenges in a safe and legal environment. You can download vulnerable machines from this website and try to exploit them. There are a lot of other challenging CTF exercises available on vulnhub.com and I highly suggest attempting them, as it is a good way to sharpen your skills and learn new techniques in a safe environment.

Please note: For all these machines, I have used Oracle VirtualBox to run the downloaded machine. I am using Kali Linux as an attacker machine for solving this CTF. The techniques used are solely for educational purposes, and I am not responsible if the listed techniques are used against any other targets.

The steps

1. Getting the IP address with the Netdiscover utility
2. Port scanning with Nmap
3. Enumerating web application
4. Cracking the password with John the Ripper
5. Analyzing and cracking the Linux password from the shadow file
6. Logging into SSH and bypassing the restricted shell
7. Getting the root with a local exploit

(Read more...)