This post documents the complete walkthrough of LazySysAdmin: 1, a boot2root VM created by Togie Mcdogie, and hosted at VulnHub. If you are uncomfortable with spoilers, please stop reading now.

Background

The story of a lonely and lazy sysadmin who :cry: himself to sleep.

Information Gathering

Let’s start with a nmap scan to establish the available services in the host.

# nmap -n -v -Pn -p- -A --reason -oN nmap.txt 192.168.20.130
...
PORT     STATE SERVICE     REASON         VERSION
22/tcp   open  ssh         syn-ack ttl 64 OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.8 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
|   1024 b5:38:66:0f:a1:ee:cd:41:69:3b:82:cf:ad:a1:f7:13 (DSA)
|   2048 58:5a:63:69:d0:da:dd:51:cc:c1:6e:00:fd:7e:61:d0 (RSA)
|   256 61:30:f3:55:1a:0d:de:c8:6a:59:5b:c9:9c:b4:92:04 (ECDSA)
|_  256 1f:65:c0:dd:15:e6:e4:21:f2:c1:9b:a3:b6:55:a0:45 (ED25519)
80/tcp   open  http        syn-ack ttl 64 Apache httpd 2.4.7 ((Ubuntu))
|_http-generator: Silex v2.2.7
| http-methods:
|_  Supported Methods: POST OPTIONS GET HEAD
| http-robots.txt: 4 disallowed entries
|_/old/ /test/ /TR2/ /Backnode_files/
|_http-server-header: Apache/2.4.7 (Ubuntu)
|_http-title: Backnode
139/tcp  open  netbios-ssn syn-ack ttl 64 Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp  open  netbios-ssn syn-ack ttl 64 Samba smbd 4.3.11-Ubuntu (workgroup: WORKGROUP)
3306/tcp open  mysql       syn-ack ttl 64 MySQL (unauthorized)
6667/tcp open  irc         syn-ack ttl 64 InspIRCd
| irc-info:
|   server: Admin.local
|   users: 1
|   servers: 1
|   chans: 0
|   lusers: 1
|   lservers: 0
|   source ident: nmap
|   source host: 192.168.20.128
|_  error: Closing link: ([email protected]) [Client exited]

I’m surprised to be honest. The host has Samba; it has MySQL. It even has InspIRCd beyond the usual http and ssh services.

Directory Enumeration

Besides the disallowed entries in robots.txt, I found the following directories with dirbuster and its largest directory wordlist.

Dir found: / - 200
Dir found: /apache/ - 200
Dir found: /Backnode_files/ - 200
Dir found: /old/ - 200
Dir found: /phpmyadmin/ - 200
Dir found: /test/ - 200
Dir found: /wordpress/ - 200
Dir found: /wp/ - 200

Hmm. The sysadmin has installed phpMyAdmin and WordPress. The rest of the directories is empty except for /Backnode_files.

Image shows phpMyAdmin

phpMyAdmin

Image shows WordPress

WordPress

Samba Share

Using Gnome Files, I was able to mount share$. Here’s what I did.

First, I connect to the Samba server.

Connect to Samba

Once connected, the available shares are in display—share$ should be interesting.

Shares

What a pleasant surprise—share$ is the webroot.

Webroot

The sysadmin is lazy indeed. Plenty of juicy information to discover in the webroot.

# cat deets.txt
CBF Remembering all these passwords.

Remember to remove this file and update your password after we push out the server.

Password 12345

This is what I’m doing lol.

# cat todolist.txt
Prevent users from being able to view to web root using the local file browser

OOPSIE WOOPSIE!!
Uwu We made a fucky wucky!!

# cat wordpress/wp-config.php
...
// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'wordpress');

/** MySQL database username */
define('DB_USER', 'Admin');

/** MySQL database password */
define('DB_PASSWORD', 'TogieMYSQL12345^^');

The sysadmin has messed up—big time.

WordPress Admin

Let’s use wpscan to identify the users in WordPress.

# wpscan --url http://192.168.20.130/wordpress --enumerate u
...
[+] Enumerating usernames ...
[+] We identified the following 1 user:
    +----+-------+---------+
    | ID | Login | Name    |
    +----+-------+---------+
    | 1  | admin | Admin – |
    +----+-------+---------+
[!] Default first WordPress username 'admin' is still used

I was lucky. The lazy sysadmin used TogieMYSQL12345^^—the database password as the password to the WordPress admin account.

WordPress Admin

Low-Privilege Shell

Now that I’ve access to WordPress as admin, I can edit one of the PHP files using WordPress Theme Editor to execute remote commands like so.

404.php

I sure can execute remote commands.

Remote Command Execution

Let’s abuse the remote command execution to get a reverse shell.

On the attacking machine, do the following:

  1. Use msfvenom to generate a reverse shell and name it as rev.
  2. Host the shell with Python SimpleHTTPServer module.
  3. Set up netcat listener to receive the shell.

On the remote command execution page, do the following:

  1. Use wget to transfer the shell over to /tmp/rev.
  2. Make the shell executable with chmod +x.
  3. Execute the reverse shell.

If everything went well, you should have a low-privilege shell like this.

Low-Privilege Shell

Privilege Escalation

We know the sysadmin is lazy and has a habit of using the same password for different accounts. That’s why I wasn’t surprised when I manage to su to togie using 12345 as the password.

togie

What’s horrifying is this—togie is able to sudo as root!

sudo

Although togie is using rbash—or restricted bash, it’s trivial to change the shell back to bash with chsh.

I Love Me Some Random Strings

ef7f90db.png

:dancer: