Tuesday, April 29, 2014

DSploit

DSploit

After playing with the applications installed on the Pwn Pad, I found that the most important application (at least for me) was missing from the pre-installed apps. Namely, DSploit. Although DSploit has a tons of features, I really liked the multiprotocol password sniffing (same as dsniff) and the session hijacking functionality.

The DSploit APK in the Play Store was not working for me, but the latest nightly on http://dsploit.net worked like a charm.

Most features require that you and your target uses the same WiFi network, and that's it. It can be Open, WEP, WPA/WPA2 Personal. On all of these networks, DSploit will sniff the passwords - because of the active attacks. E.g. a lot of email clients still use IMAP with clear text passwords, or some webmails, etc. 

First, DSploit lists the AP and the known devices on the network. In this case, I chose one victim client.


In the following submenu, there are a tons of options, but the best features are in the MITM section. 


Stealthiness warning: in some cases, I received the following popup on the victim Windows:


This is what we have under the MITM submenu:


Password sniffing

For example, let's start with the Password Sniffer. It is the same as EvilAP and DSniff in my previous post. With the same results for the popular hungarian webmail with the default secure login checkbox turned off. Don't forget, this is not an Open WiFi network, but one with WPA2 protection!


Session hijack

Now let's assume that the victim is very security aware and he checks the secure login checkbox. Another case can be that the victim already logged in, long before we started to attack. The session hijacking function is similar to the Firesheep tool, but it works with every website where the session cookies are sent in clear text, and there is no need for any additional support.

In a session hijacking attack (also called "sidejacking"), after the victim browser sends the authentication cookies in clear text, DSploit copies these cookies into it's own browser, and opens the website with the same cookies, which results successful login most of the time. Let's see session hijacking in action!

Here, we can see that the session cookies has been sniffed from the air:


Let's select that session, and be amazed that we logged into the user's webmail session.




Redirect traffic

This feature can be used both for fun or profit. For fun, you can redirect all the victim traffic to http://www.kittenwar.com/. For profit, you can redirect your victim to phishing pages.


Replace images, videos

I think this is just for fun here. Endless Rick Rolling possibilities.


Script injection

This is mostly for profit. client side injection, drive-by-exploits, endless possibilities.

Custom filter

If you are familiar with ettercap, this has similar functionalities (but dumber), with string or regex replacments. E.g. you can replace the news, stock prices, which pizza the victim ordered, etc. If you know more fun stuff here, please leave a comment (only HTTP scenario - e.g. attacking Facebook won't work).

Additional fun (not in DSploit) - SSLStrip 

From the MITM section of DSploit, I really miss the SSLStrip functionality. Luckily, it is built into the Pwn Pad. With the help of SSLStrip, we can remove the references to HTTPS links in the clear text HTTP traffic, and replace those with HTTP. So even if the user checks the secure login checkbox at freemail.hu, the password will be sent in clear text - thus it can be sniffed with DSniff.

HTML source on the client side without SSLstrip:


HTML source on the client side with SSL strip:


With EvilAP, SSLStrip, and DSniff, the password can be stolen. No hacking skillz needed.

Lessons learned here

If you are a website operator where you allow you users to login, always:
  1. Use HTTPS with a trusted certificate, and redirect all unencrypted traffic to HTTPS ASAP
  2. Mark the session cookies with the secure flag
  3. Use HSTS to prevent SSLStrip attacks
If you are a user:
  1. Don't trust sites with your confidential data if the above points are not fixed. Choose a more secure alternative
  2. Use HTTPS everywhere plugin
  3. For improved security, use VPN
Because hacking has been never so easy before.
And last but not least, if you like the DSploit project, don't forget to donate them!

Tuesday, April 22, 2014

WiFi hacking on tablets

Disclaimer: Don't hack anything where you don't have the authorisation to do so. Stay legal.

Ever since I bought my first Android device, I wanted to use the device for WEP cracking. Not because I need it, but I want it :) After some googling I read that you can't use your WiFi chipset for packet injection, and I forgot the whole topic.

After a while I read about hacking on tablets (this was around a year ago), and my first opinion was: 
"This is stupid, lame, and the usage of that can be very limited".

After playing one day with it, my opinion just changed: 
"This is stupid, lame, the usage is limited, but when it works, it is really funny :-)"

At the beginning I looked at the Pwn Pad as a device which can replace a pentest workstation, working at the attacker side. Boy was I wrong. Pwn Pad should be used as a pentest device deployed at the victim side!

You have the following options:
  1. You have 1095 USD + VAT + shipping to buy this Pwn Pad
  2. You have around 200 USD to buy an old Nexus 7 tablet, an USB OTG cable, a USB WiFi dongle (e.g. TP-Link Wireless TL-WN722N USB adapter works).



In my example, I bought a used, old 2012 Nexus WiFi. Originally I bought this to play with different custom Android ROMs, and play with rooted applications. After a while I found this Pwn Pad hype again, and gave it a shot.

The Pwn Pad community edition has an easy-to-use installer, with a proper installation description. Don't forget to backup everything from your tablet before installing Pwn Pad on it!

I don't want to repeat the install guide, it is as easy as ABC. I booted a Ubuntu Live CD, installed adb and fastboot, and it was ready-to-roll. I have not measured the time, but the whole process was around 20 minutes.


The internal WiFi chipset can be used to sniff traffic, or even ARP poisoning for active MiTM. But in my case, I was not able to use the internal chipset for packet injection, which means you can't use it for WEP cracking, WPA disauth, etc. This is where the external USB WiFi comes handy. And this is why we need the Pwn Pad Android ROM, and can't use an average ROM.

There are two things where Pwn Pad really rocks. First one is the integrated drivers for the external WiFi with monitor mode and packet injection capabilities. The second cool thing is the chroot wrapper around the Linux hacking tools. Every hacking tool has a start icon, so it feels like it is a native Android application, although it is running in a chroot Kali environment.

Wifite

The first recommended app is Wifite. Think of it as a wrapper around the aircrack - airmon - airodump suite. My biggest problem with WEP cracking was that I had to remember a bunch of commands, or have the WEP cracking manual with me every time I have to crack it. It was overcomplicated. But thanks to Wifite, that is past.

In order to crack a WEP key, you have to:
  1. Start the Wifite app
  2. Choose your adapter (the USB WiFi)

  3. Choose the target network (wep_lan in the next example)
  4. Wait for a minute 
  5. PROFIT!

SSH reverse shell

This is one of the key functionalities of the Pwn Pad. You deploy the tablet at the Victim side, and let the tablet connect to your server via (tunneled) SSH.

The basic concept of the reverse shells are that an SSH tunnel is established between the Pwn Pad tablet (client) and your external SSH server (either directly or encapsulated in other tunneling protocol), and remote port forward is set up, which means on your SSH server you connect to a localport which is forwarded to the Pwn Pad and handled by the Pwn Pad SSH server.

I believe the best option would be to use the reverse shell over 3G, and let the tablet connect to the victim network through Ethernet or WiFi. But your preference might vary. The steps for reverse shells are again well documented in the documentation, except that by default you also have to start the SSH server on the Pwn Pad. It is not hard, there is an app for that ;-) On your external SSH server you might need to install stunnel and ptunnel if you are not using Kali. The following output shows what you can see on your external SSH server after successfull reverse shell.

root@myserver:/home/ubuntu# ssh -p 3333 pwnie@localhost
The authenticity of host '[localhost]:3333 ([127.0.0.1]:3333)' can't be established.
ECDSA key fingerprint is 14:d4:67:04:90:30:18:a4:7a:f6:82:04:e0:3c:c6:dc.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[localhost]:3333' (ECDSA) to the list of known hosts.
pwnie@localhost's password:
  _____      ___  _ ___ ___   _____  _____ ___ ___ ___ ___
 | _ \ \    / / \| |_ _| __| | __\ \/ / _ \ _ \ __/ __/ __|
 |  _/\ \/\/ /| .` || || _|  | _| >  <|  _/   / _|\__ \__ \
 |_|   \_/\_/ |_|\_|___|___| |___/_/\_\_| |_|_\___|___/___/

 Release Version: 1.5.5
 Release Date: 2014-01-30
 Copyright 2014 Pwnie Express. All rights reserved.

 By using this product you agree to the terms of the Rapid Focus
 Security EULA: http://pwnieexpress.com/pdfs/RFSEULA.pdf

 This product contains both open source and proprietary software.
 Proprietary software is distributed under the terms of the EULA.
 Open source software is distributed under the GNU GPL:
 http://www.gnu.org/licenses/gpl.html

pwnie@localhost:~$

Now you have a shell on a machine which is connected to the victim network. Sweet :) Now Metasploit really makes sense on the tablet, and all other command line tools.

EvilAP and DSniff

Start EvilAP (it is again a wrapper around airobase), choose interface (for me the Internal Nexus Wifi worked), enter an SSID (e.g freewifi), enter channel, choose whether force all clients to connect to you or just those who really want to connect to you, and start.


Next step is start DSniff, choose interface at0, and wait :) In this example, I used a popular hungarian webmail, which has a checkbox option for "secure" login (with default off). There are sooo many problems with this approach, e.g.  you can't check the certificate before connecting, and the login page is delivered over HTTP, so one can disable the secure login checkbox seamlessly in the background, etc. In this case, I left the "secure" option on default off.



In the next tutorial, I'm going to show my next favorite app, DSploit ;)

Lessons learned

Hacking has been never so easy before
In a home environment, only use WPA2 PSK
Choose a long, nondictionary passphrase as the password for WPA2
Don't share your WiFi passwords with people you don't trust, or change it when they don't need it anymore
Don't let your client device auto connect to WiFi stations, even if the SSID looks familiar

I believe during an engagement a Pwn Plug has better "physical cloaking" possibilities, but playing with the Pwn Pad Community Edition really gave me fun moments.

And last but not least I would like to thank to the Pwn Pad developers for releasing the Community Edition!

Thursday, April 3, 2014

Tricks to Bypass Device Control Protection Solutions

Preface

As I wrote in a previous blog post, I had an engagement last year where my task was to exfiltrate data from a workstation on some sort of storage media. The twist in that task was Lumension Sanctuary Device Control, and the version was 4.3.2, but I am not sure how newer version work and this seems to be a more general problem with device control solution, for example with Symantec products.

But what is a device control solution? In short, they audit I/O device use and block the attempts to use unauthorized devices. This includes hardware such as USB, PS/2, FireWire, CD/DVD so basically every I/O port of a computer. In my opinion, these are pretty good things and they offer a better looking solution than de-soldering the I/O ports from the motherboards or hot-gluing them, but on the other hand, they can be bypassed.

Bypass

OK, so what is the problem? Well the way these device control solutions work is that they load a few kernel drivers to monitor the physical ports of the machine. However... when you boot up the protected computer in safe mode, depending on the device control solution software, some of these drivers are not loaded (or if you are lucky, none of those modules will be loaded...) and this opens up the possibility to exfiltrate data.

In theory, if you have admin (SYSTEM maybe?) privileges, you might as well try to unload the kernel drivers. Just do not forget, that these device control solutions also have a watchdog process, that checks the driver and automatically loads it back if it is unloaded, so look for that process and stop or suspend it first.

In my case with the Lumension Sanctuary Device Control, I have found that when I boot the Workstation protected by the device control software in Safe Mode where, software’s key logger protection module is not running... so I was still unable to use a USB stick, or a storage media, but I could plug in a keyboard for example...hmmm :)

As some of you probably already figured it out, now it is possible to use a pre-programmed USB HID, for example a Teensy! : ) I know about three different project, that uses this trick like these two mentioned in a Hackaday post, or this one. Unfortunately, the site ob-security.info no longer seems to be available (well, at least it is no longer related to infosec :D ), but you can still find the blog post and the files with the Wayback Machine.

For the hardware part, the wiring of the Teensy and the SD card adaptor is the same as I showed in the post on Making a USB flash drive HW Trojan or in the Binary deployment with VBScript, PowerShell or .Net csc.exe compiler post, so I will not copy it here again.

I have to note here that there are other ways to bypass these device control solutions, like the method what Dr. Phil Polstra did with the USB Impersonator, which is basically looks for an authorized device VID/PID and then  impersonates that devices with the VID/PID.

Mitigation

Most probably, you will not need safe mode for the users, so you can just disable it... I mean, it is not that easy, but luckily there is a great blog post on how to do that. BTW, the first page of the post is for Windows XP, but you are not using XP anymore, aren't you? ;)

Alternatively, as I mentioned at the beginning, you might as well use some physical countermeasure (de-soldering/hot-gluing ports). That shit is ugly, but it kinda works.

Conclusion

Next time you will face a device control solution, try out these tricks, maybe they will work, and if they do, well, that's a lot of fun. :)

But don't get me wrong, these device control solutions and similar countermeasures are a good thing and you should use something like this! I know that they make doing business a bit harder as you are not able to plugin whatever USB stick you want, but if you buy a pile of hardware encrypted flash drives, and only allow  those to be plugged in, you are doing it right ;)

Tuesday, April 1, 2014

BYOPPP - Build your own privacy protection proxy

I have read a blog post, where you can build your own privacy proxy server built on Raspberry PI. The post got me thinking about how I can use this to protect my privacy on my Android phone, and also get rid of those annoying ads. 

Since I own a Samsung Galaxy S3 LTE with Android 4.3 (with a HW based Knox counter), rooting the phone now means you break Knox, and loose warranty. Past the point of no return ...

This means I have to solve this without root. Luckily newer Androids support VPN without rooting, but setting a mandatory system-wide proxy is still not possible without root. 
But thanks to some iptables magic and Privoxy, this is not a problem anymore :) 

The ingredients to build your own privacy protection proxy:
  • One (or more) cheap VPS server(s)
  • a decent VPN program
  • Privoxy
  • iptables

VPS server

To get the cheap VPS server, I recommend using Amazon EC2, but choose whatever you like. The micro instance is very cheap (or even free), and has totally enough resources for this task. I'm using the Ubuntu free tier now and it works like a charm. And last but not least Amazon has two-factor authentication! You can setup an Ubuntu server under 10 minutes. Use the AWS region nearest to you, e.g. I choosed EU - Ireland.



VPN

For the VPN program, I recommend the free version of the OpenVPN AS (EDIT: be sure to use OpenVPN AS 2.0.6 or later, both on the server and the client). Easy to set-up quick start guide is here, GUI based configuration, and one-click client installer for Android, iOS, Windows, Linux, OSX. The Ubuntu installer packages are here.




The most important settings:

  • I prefer to use the TCP 443 and UDP 53 ports for my OpenVPN setup, and let the user guess why. 
  • For good performance, UDP is preferred over TCP. 
  • VPN mode is Layer 3 (routing/NAT).
  • Don't forget to allow the configured VPN ports in the AWS firewall (security groups). 


Other VPN settings:
  • Should VPN clients have access to private subnets (non-public networks on the server side)? - Yes
  • Should client Internet traffic be routed through the VPN? - Yes

Privoxy

The next component we have to install and configure is Privoxy. As usual, "apt-get install privoxy" just works. The next step is to configure privoxy via /etc/privoxy/config file, there are two options to change:
  • listen-address your.ip.add.ress:8118
  • accept-intercepted-requests 1
Beware not to allow everyone accessing your Privoxy server in the AWS EC2 security groups, be sure it is reachable only to VPN users!

After everything is set, start privoxy with "service privoxy start", and add it to the autostart "update-rc.d privoxy defaults".

Iptables

And the final step is to configure your iptables chain to forward every web traffic from the VPN clients to the Privoxy server:

iptables -t nat -A PREROUTING -s 5.5.0.0/16 -p tcp -m multiport --dports 80,8080,81 -j DNAT --to-destination your.ip.add.ress:8118

Optionally you can block access to all other ports as well, and what does not go through your Privoxy won't be reachable.
Based on your Linux distribution and preference, you might make this rule persistent.

Final test

Now you can connect to the VPN server from your Android device.
After logging in from a client, you get the following nice packages to install on your device:


After connecting, the final results can be seen on the following screenshots. And yes, there is a reason I chose Angry Birds as an example.

Angry Birds without Privoxy
Angry Birds with Privoxy
Stupid flashlight app with ad
Stupid flashlight app with Privoxy
Spoiler alert
If you are afraid of NSA tracking you, this post is not for you. If you want to achieve IP layer anonymity, this post is not for you. As long as you are the only one using that service, it should be trivial to see what could possibly go wrong with that.

Known issues
Whenever the Internet connection (Wifi, 3G) drops, the VPN connection drops as well, and your privacy is gone ...
Sites breaking your privacy through SSL can still do that it as long as the domain is not in the Privoxy blacklist.

Additional recommendation
If you are using OSX or Windows, I can recommend Aviator to be used as your default browser. It is just great, give it a try!

PS: There are also some adblock apps removed from the official store which can block some ads, but you have to configure a proxy for every WiFi connection you use, and it is not working over 3G.