A few years ago we made the difficult, and sometimes painful, shift to enable remote working in preparation for the opening of our UK and Cape Town offices. Some of you probably think this is a no-brainer, but the benefit of being in the same room as your fellow hackers can't be overlooked. Being able to call everyone over to view an epic hack, or to ask for a hand when stuck is something tools like Skype fail to provide. We've put a lot of time into getting the tech and processes in place to give us the "hackers in the same room" feel, but this needs to be backed with some IRL interaction too.
People outside of our industry seem to think of "technical" people as the opposite of "creative" people. However, anyone who's slung even a small amount of code, or even dabbled in hacking will know this isn't true. We give our analysts "20% time" each month to give that creativity an outlet (or to let on-project creativity get developed further). This is part of the intention of SenseCon: a week of space and time for intense learning, building, and just plain tinkering without the stresses of report deadlines or anything else.
But, ideas need input, so we try to organise someone to teach us new tricks. This year that was done by Schalk from House 4 Hack (these guys rocks) who gave us some electronic and Arduino skills and some other internal trainings. Also, there's something about an all-nighter that drives creativity, so much so that some Plakkers used to make sure they did one at least once a month. We use our hackathon for that.
Our hackathon's setup is similar to others - you get to pitch an idea, see if you can get two other team mates on board, and have 24 hours to complete it. We had some coolness come out of this last year and I was looking forward to seeing what everyone would come up with this time round.
Copious amounts of energy drinks, snacks, biltong and chocolates were on supply and it started after dinner together. The agreed projects were are listed below, with some vagueness, since this was internal after all :)
Keiran and Dane put our office discone antenna to good use and implemented some SDR-fu to pick up aeroplane transponder signals and decode them. They didn't find MH370, but we now have a cool plane tracker for SP.
Using wifi-deauth packets can be useful if you want to knock a station (or several) off a wifi network. Say you wanted to prevent some cheap wifi cams from picking you up ... Doing this right can get complicated when you're sitting a few km's away with a yagi and some binoculars. Charl got an arduino to raise a flag when it was successfully deauthed, and lower it when connectivity is restored for use in a wifi-shootout game.
Panda (Jeremy) and Sara ended up building local Maltego transforms that would allow mass/rapid scanning of large netblocks so you can quickly zoom in on the most vulnerable boxes. No countries were harmed in the making of this.
gcp and et decided on some good ol'fashioned fuzz-n-find bug hunting on a commercial mail platform, and websense. Along the way they learned some interesting lessons in how not to fuzz, but in the end found some coolness.
The hackathon went gangbusters; most of the team went through the night and into the morning (I didn't, getting old and crashed at 2am). Returning that morning to see everyone still hacking away on their projects (and a few hacking away on their snoring) was amazing.
Once the 24-hours was up, many left the office to grab a shower and refresh before having to present to the entire company later on that afternoon.
Overall this years SenseCon was a great success. Some cool projects/ideas were born, a good time was had AND we even made Charl feel young again. As the kids would say, #winning
nmap -sV -Pn --versiondb=nmap-service-probes.pi --script=poison-ivy.nse <ip_address/range)
nmap -sV -Pn --versiondb=nmap-service-probes.pi <ip_range>
If you have any questions, please contact email@example.com
Recently a security researcher reported a bug in Facebook that could potentially allow Remote Code Execution (RCE). His writeup of the incident is available here if you are interested. The thing that caught my attention about his writeup was not the fact that he had pwned Facebook or earned $33,500 doing it, but the fact that he used OpenID to accomplish this. After having a quick look at the output from the PoC and rereading the vulnerability description I had a pretty good idea of how the vulnerability was triggered and decided to see if any other platforms were vulnerable.
The basic premise behind the vulnerability is that when a user authenticates with a site using OpenID, that site does a 'discovery' of the user's identity. To accomplish this the server contacts the identity server specified by the user, downloads information regarding the identity endpoint and proceeds with authentication. There are two ways that a site may do this discovery process, either through HTML or a YADIS discovery. Now this is where it gets interesting, HTML look-up is simply a HTML document with some meta information contained in the head tags:
Whereas the Yadis discovery relies on a XRDS document:
Now if you have been paying attention the potential for exploitation should be jumping out at you. XRDS is simply XML and as you may know, when XML is used there is a good chance that an application may be vulnerable to exploitation via XML External Entity (XXE) processing. XXE is explained by OWASP and I'm not going to delve into it here, but the basic premise behind it is that you can specify entities in the XML DTD that when processed by an XML parser get interpreted and 'executed'.
From the description given by Reginaldo the vulnerability would be triggered by having the victim (Facebook) perform the YADIS discovery to a host we control. Our host would serve a tainted XRDS and our XXE would be triggered when the document was parsed by our victim. I whipped together a little PoC XRDS document that would cause the target host to request a second file (198.x.x.143:7806/success.txt) from a server under my control. I ensured that the tainted XRDS was well formed XML and would not cause the parser to fail (a quick check can be done by using http://www.xmlvalidation.com/index.php)
In our example the fist <Service> element would parse correctly as a valid OpenID discovery, while the second <Service> element contains our XXE in the form of <URI>&a;</URI>. To test this we set spun up a standard LAMP instance on DigitalOcean and followed the official installation instructions for a popular, OpenSource, Social platform that allowed for OpenID authentication. And then we tried out our PoC.
It worked! The initial YADIS discovery (orange) was done by our victim (107.x.x.117) and we served up our tainted XRDS document. This resulted in our victim requesting the success.txt file (red). So now we know we have some XXE going on. Next we needed to turn this into something a little more useful and emulate Reginaldo's Facebook success. A small modification was made to our XXE payload by changing the Entity description for our 'a' entity as follows: <!ENTITY a SYSTEM 'php://filter/read=convert.base64-encode/resource=/etc/passwd'>. This will cause the PHP filter function to be applied to our input stream (the file read) before the text was rendered. This served two purposes, firstly to ensure the file we were reading to introduce any XML parsing errors and secondly to make the output a little more user friendly.
The first run with this modified payload didn't yield the expected results and simply resulted in the OpenID discovery being completed and my browser trying to download the identity file. A quick look at the URL, I realised that OpenID expected the identity server to automatically instruct the user's browser to return to the site which initiated the OpenID discovery. As I'd just created a simple python web server with no intelligence, this wasn't happening. Fortunately this behaviour could be emulated by hitting 'back' in the browser and then initiating the OpenID discovery again. Instead of attempting a new discovery, the victim host would use the cached identity response (with our tainted XRDS) and the result was returned in the URL.
Finally all we needed to do was base64 decode the result from the URL and we would have the contents of /etc/passwd.
This left us with the ability to read *any* file on the filesystem, granted we knew the path and that the web server user had permissions to access that file. In the case of this particular platform, an interesting file to read would be config.php which yields the admin username+password as well as the mysql database credentials. The final trick was to try and turn this into RCE as was hinted in the Facebook disclosure. As the platform was written in PHP we could use the expect:// handler to execute code. <!ENTITY a SYSTEM 'expect://id'>, which should execute the system command 'id'. One dependency here is that the expect module is installed and loaded (http://de2.php.net/manual/en/expect.installation.php). Not too sure how often this is the case but other attempts at RCE haven't been too successful. Armed with our new XRDS document we reenact our steps from above and we end up with some code execution.
And Boom goes the dynamite.
All in all a really fun vulnerability to play with and a good reminder that data validation errors don't just occur in the obvious places. All data should be treated as untrusted and tainted, no matter where it originates from. To protect against this form of attack in PHP the following should be set when using the default XML parser:
A good document with PHP security tips can be found here: http://phpsecurity.readthedocs.org/en/latest/Injection-Attacks.html
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
Botconf'13, the "First botnet fighting conference" took place in Nantes, France from 5-6 December 2013. Botconf aimed to bring together the anti-botnet community, including law enforcement, ISPs and researchers. To this end the conference was a huge success, especially since a lot of networking occurred over the lunch and tea breaks as well as the numerous social events organised by Botconf.
I was fortunate enough to attend as a speaker and to present a small part of my Masters research. The talk focused the use of Spatial Statistics to detect Fast-Flux botnet Command and Control (C2) domains based on the geographic location of the C2 servers. This research aimed to find novel techniques that would allow for accurate and lightweight classifiers to detect Fast-Flux domains. Using DNS query responses it was possible to identify Fast-Flux domains based on values such as the TTL, number of A records and different ASNs. In an attempt to increase the accuracy of this classifier, additional analysis was performed and it was observed that Fast-Flux domains tended to have numerous C2 servers widely dispersed geographically. Through the use of the statistical methods employed in plant and animal dispersion statistics, namely Moran's I and Geary's C, new classifiers were created. It was shown that these classifiers could detect Fast-Flux domains with up to a 97% accuracy, maintaining a False Positive rate of only 3.25% and a True Positive rate of 99%. Furthermore, it was shown that the use of these classifiers would not significantly impact current network performance and would not require changes to current network architecture.
The scripts used to conduct the research are available on github and are in the process of being updated (being made human readable): https://github.com/staaldraad/fastfluxanalysis
The following blogs provide a comprehensive round-up of the conference including summaries of the talks: