We recently ran our Black Hat challenge where the ultimate prize was a seat on one of our training courses at Black Hat this year. This would allow the winner to attend any one of the following:
Simply trying out this feature and viewing how it functions. Viewing the feed tester result, we noticed that the contents of the XML formatted RSS feed were echoed and it became clear that this may be vulnerable to XXE. The first step would be to try a simple XML payload such as:
It looks like we have some more XML being submitted.. Again we tried XXE and found that using "file://" in our payload created an error. There were ways around this, however the returned data would be truncated and we would not be able to see the full contents of flag2.txt... When stuck with XXE and not being able to see the result (or complete result) there is always the chance that we can get the data out via the network. To do this we needed to generate a payload that would allow us to fetch an external DTD and then "submit" the contents of our target file to a server under our control. Our payload on our server looked like this:
As soon as the XML decoder parsed our malicious payload, we would receive the base64 encoded contents on our server:
Now it was a simple matter of decoding the payload and we had the second flag. This was not the only way to get flag 2! It was the most "fun" way of doing it though and used a really handy method. Remember it for your next pentest...
The two runners up who both can claim one of our awesome 2014 t-shirts:
Vitaly aka @send9
Sash aka @secdefect
Wireless hacking, you say?
You may think wireless hacking is nothing new, and you may think it's just not that relevant or exciting. Come along to our BlackHat Wireless Bootcamp course and we'll show you different! We'll teach you the fundamentals every wireless hacker needs to know, but then move onto the really exciting, cutting edge stuff.
Cutting edge WiFi hacking, you say?
At SensePost we really enjoy wireless hacking - mostly because it gets us good results in terms of compromising our targets! With our years of experience in this area we've written our own tools, as well as refined others. In this course we'll reveal new techniques and tools (can you smell 0day?) that we'll hopefully be presenting at the conference, and give you exclusive hands on training with our very own Snoopy framework (a distributed, tracking, data interception, and profiling framework). Two lucky students who capture our CTFs will also go home with pre-built Snoopy drone. Every student will also get their own Alfa WiFi card to take home, as well as the latest Snoopy pre-release (Snoopy will run fine on your laptop too).
Here's an exact break down of what to expect from this course:
• Wi-Fi theory and background
• Breaking WEP
• Breaking WPA PSK
• Man in the middle attacks for WPA MGT (new attack vectors)
• Breaking WPS
• Wi-Fi Router back doors
• Rogue Access Points attack scenarios (new attack vectors)
• Exclusive Snoopy training
Who should attend?
Anyone interested in WiFi security. The course is relevant for both attackers and defenders (it'll let you put your defense into context). Students should have some technical ability in Linux, and understand networking fundamentals, but this is a bootcamp level course.
Dominic (@singe) and Glenn (@glennzw) will be your instructors. They're both avid wireless hackers, and never leave home without a high gain antenna and an Alfa card! They're looking forward to training you. You can find the sign-up page here.
-Glenn & Dominic
Aah, January, a month where resolutions usually flare out spectacularly before we get back to the couch in February. We'd like to help you along your way with a reverse engineering challenge put together by Siavosh as an introduction to reversing, and a bit of fun.
Once you reached the final levels, you might need to spend some time understanding x86 assembly or spend some time refreshing it depending on your level. To help out, Siavosh created a crash course tutorial in x86 assembly for our malware workshop at 44con last year, and you can download that over here.
The zip file containing the reversing challenge and additional bytecode binaries could be found here.
Send your solution(s) to challenge at sensepost.com
Disclaimer: When using the term "virtual machine" we mean something like the Java Virtual Machine. A software based architecture that you can write programs for. This particular architecture, EvilGroupVM.exe, has nine instructions whose operation code (opcode) you need to find through binary reverse engineering.
The tools you will require are:
Windows: EvilGroupVM.exe <BytecodeFile>
Ubuntu Linux: ./EvilGroupVM <BytecodeFile>
The outcome of this exercise should include the following key structures in your report:
In case you missed it earlier, the zip file containing the reversing challenge and additional bytecode binaries could be found here.
Send your solution(s) to challenge at sensepost.com
We recently gave a talk at the ITWeb Security Summit entitled "Offense Oriented Defence". The talk was targeted at defenders and auditors, rather then hackers (the con is oriented that way), although it's odd that I feel the need to apologise for that ;)
The talks primary point, was that by understanding how attackers attack, more innovative defences can be imagined. The corollary was that common defences, in the form of "best practise" introduce commonality that is more easily exploited, or at least degrade over time as attackers adapt. Finally, many of these "security basics" are honestly hard, and we can't place the reliance on them we'd hoped. But our approach doesn't seem to want to acknowledge the problem, and much like an AA meeting, it's time we recognise the problem.
If you had to look at the average security strategy or budget items, you often end up with a list containing a couple of these:
But, the truth is many of these items don't actually block attacks, or the few that do, don't really counter the common bypassed used to side-step them. For example:
The current place we seem to be in is akin to having everyone build a wall. Attackers get to evaluate the wall, figure out how to get over it, and add to their capability (i.e. get a longer rope). But once they have a longer rope, they can use it over and over again, and against more than one wall. So attackers, who are quite good at sharing, get to keep building their tool chain, while all defenders can do it to keep building a higher wall, and maintaining the increasingly untenable structure. By understanding how attackers attack, we can break out of this and try more innovative approaches.
The talk is illustrated with four broad examples: Passwords, Patches, Anti-Virus and DMZs. For each, the belief around specific configurations is discussed, and how those don't stand up to how attackers actually attack. For example, the way AV's believed to work doesn't seem to correspond with how easy they are to bypass, or the common configuration of standard password controls such as lockout, don't seem to take into account horizontal brute-force attacks.
The point I want to make here is somewhat subtle; if you walk away thinking I've described new attacks, then you've missed it, if you think I'm recommending "the basics" then you've missed it. Truthfully, maybe it's just that I didn't make it very well ... decide for yourself, here are the slides:
One of the things we try and get across in our training - is that pen-testing requires out of the box thinking. It's also about solving puzzles and making things work the way you want them to. It's about identifying the small vulnerabilities (which are often easy to spot), and trying to leverage them into something useful. A key process we strive to do at SensePost, when performing these penetration tests, is about having fun.
However, since we're not presenting our HBN Combat course at BlackHat this year, we thought we'd treat people to a nice, mind-boggling challenge prior to BlackHat. Furthermore, instead of opting for the normal crypto or reversing-type challenges which seem to have become the norm, we thought we'd make it an infrastructure challenge for once. In other words, people get to compromise real, live boxen. We've also made it real-world, this is something you might be faced with when performing a infrastructure test.
You've been tasked with performing an infrastructure assessment against ACME Bank. You've fired up your favorite foot printing tool, run through the usual intelligence gathering methodology and noticed they seem to have a minute Internet footprint. So small, in fact, that the only entry point you have is what appears to be a router at 22.214.171.124.
Obtain access to a host on the internal network and put your name on the wall of fame. The first name on the wall wins.
If one takes a quick glimpse at the target, it will be obvious that the person who makes the first break is probably going to be able to control what other people do (with great power comes great responsibility). Also, there is probably a relatively high chance of people inadvertently blocking themselves off from the target. As such, the challenge is going to be reset to "factory default" at 04h00 MT every day.
We've created a very cool SensePost Blackhat USA 2013 t-shirt and this is limited edition to SensePost staff only, but for the person who gets the first name on the wall, we think you deserve your own.
Have fun, happy haxoring, and hope to see you all at BlackHat.