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Mon, 4 Mar 2013

Vulnerability Management Analyst Position


Have a keen interest on scanning over 12000 IP's a week for vulnerabilities? Excited about the thought of assessing over 100 web applications for common vulnerabilities? If so, an exciting, as well as demanding, position has become available within the Managed Vulnerability Scanning (MVS) team at SensePost.


Job Title: Vulnerability Management Analyst


Salary Range: Industry standard, commensurate with experience


Location: Johannesburg/Pretoria, South Africa


We are looking for a talented person to join our MVS team to help manage the technology that makes up our Broadview suite and, more importantly, finding vulnerabilities, interpreting the results and manually verifying them. We are after talented people with a broad skill set to join our growing team of consultants. Our BroadView suite of products consists of our extensive vulnerability scanning engine, which looks at both the network-layer and the application layer, as well as our extensive DNS footprinting technologies.


The role of the Vulnerability Management Analyst will possess the following skills:


  • Be able to multitask and meet client deadlines. We want a person that thinks 'I can do that!'

  • Possess excellent written and oral communication skills. Being able to understand a vulnerability and explain it to business leaders is a must.

  • A working knowledge of enterprise vulnerability management products and remedial work flow

  • A broad knowledge of most common enterprise technologies and operating systems

  • A passion for security and technology


Some additional conditions:

  • A post graduate degree or infosec certification would be beneficial, however, showing us you have the passion and skills also helps

  • This job requires some after-hours and weekend commitments (we try to keep this to a minimum)

  • Bonus points for knowledge of sed, awk and python, ok even ruby.

  • PCI-QSA is desired but not required


Impress us with your skills by sending an email to jobs@sensepost.com and lets take it from there.


SensePost is an equal opportunity partner.

Thu, 14 Feb 2013

Adolescence: 13 years of SensePost

Today was our 13th birthday. In Internet years, that's a long time. Depending on your outlook, we're either almost a pensioner or just started our troublesome teens. We'd like to think it's somewhere in the middle. The Internet has changed lots from when SensePost was first started on the 14th February 2000. Our first year saw the infamous ILOVEYOU worm wreak havoc across the net, and we learned some, lessons on vulnerability disclosure, a year later we moved on to papers about "SQL insertion" and advanced trojans. And the research continues today.


We've published a few tools along the way, presented some (we think) cool ideas and were lucky enough to have spent the past decade training thousands of people in the art of hacking. Most importantly, we made some great friends in this community of ours. It has been a cool adventure, and indeed still very much is, for everyone who's has the pleasure of calling themselves a Plak'er. Ex-plakkers have gone on to do more great things and branch out into new spaces. Current Plakkers are still doing cool things too!


But reminiscing isn't complete without some pictures to remind you just how much hair some people had, and just how little some people's work habit's have changed. Not to mention the now questionable fashion.



Fast forward thirteen years, the offices are fancier and the plakkers have become easier on the eye, but the hacking is still as sweet.



As we move into our teenage years (or statesman ship depending on your view), we aren't standing still or slowing down. The team has grown; we now have ten different nationalities in the team, are capable of having a conversation in over 15 languages, and have developed incredible foos ball skills.


This week, we marked another special occasion for us at SensePost: the opening of our first London office in the trendy Hackney area (it has "hack" in it, and is down the road from Google, fancy eh?). We've been operating in the UK for some time, but decided to put down some roots with our growing clan this side of the pond.



And we still love our clients, they made us who we are, and still do. Last month alone, the team was in eight different countries doing what they do best.


But with all the change we are still the same SensePost at heart. Thank you for reminiscing with us on our birthday. Here's to another thirteen years of hacking stuff, having fun and making friends.

Fri, 14 Dec 2012

Dangers of Custom ASP.NET HttpHandlers

ASP.NET HttpHandlers are interesting components of a .NET web application when performing security assessments, mainly due to the fact they are the most exposed part of the application processing client requests in HttpContext level and at the same time, not yet part of the official ASP.NET framework.


As a result, data validation vulnerabilities in custom HttpHandlers can be exploited far easier than issues on the inner layer components. However, they are mostly overlooked during the web application tests for two reasons:


  1. They are used by a 3rd party component of a target application and often the auditor wants to focus on the main functions of the application

  2. They often are found performing such operations as displaying an icon file or chart from image cache. This is deemed useless during an assessment.


In this post, I'm going to demonstrate a data validation vulnerability in a custom HttpHandler which is used by a number of well known ASP.NET apps such as DotNetNuke CMS and was not fixed by the vendor until 2012/3. We still come across web applications that use this vulnerable component, so thought it useful that we document this vulnerability in the Telerik ASP.NET UI Control, which could allow a remote user to download and remove files from the web server under application's pool permission.


If you are using any of the Telerik components in your application, make sure to replace the "Telerik.Web.UI.dll" with the latest version (about 9MB!).


Vulnerability details:


The Telerik UI control has a web-based charts feature, which stores rendered graphic files in a cache folder for performance reasons. It registers a custom HttpHandler in the web.config file, which processes the following GET request and displays the chart in the client browser:


http://site/ChartImage.axd?useSession=false&imageFormat=image/png&ImageName=[base64 encoded value]


The next step is to decompile the code of the ChartHttpHandler.ProcessRequest(HttpContext), which gives us:



Although, the ImageName query string parameter is encrypted using an AES algorithm to prevent tampering, the encryption key and initialization vector are embedded in the application's assembly (Telerik.Web.UI.dll) and can be used to construct malicious requests to download files from the remote server, as shown in the following figure:



All versions up to and including 2011.2.915.35 are vulnerable. I've created a proof of concept that can be downloaded here . Please note that the target file will be deleted from the web server by the chart image handler after being downloaded from the server, as it considers the requested file as an expired cache entry.


Next time you are on an assessment, don't overlook the mundane and not-so-interesting parts of the application, as they can often provide you with an additional attack surface area.

Mon, 26 Nov 2012

Skype Passive IP Disclosure Vulnerability

When performing spear phishing attacks, the more information you have at your disposal, the better. One tactic we thought useful was this Skype security flaw disclosed in the early days of 2012 (discovered by one of the Skype engineers much earlier).

For those who haven't heard of it - this vulnerability allows an attacker to passively disclose victims external, as well as internal, IP addresses in a matter of seconds, by viewing the victims VCard through an 'Add Contact' form.

Why is this useful?

1. Verifying the identity and the location of the target contact. Great when performing geo-targeted phishing attacks.

2. Checking whether your Skype account has not been used elsewhere :)

3. Spear phishing enumeration while Pen Testing.

4. Just out of plain curiosity.

To get this working, following these basic steps:

1. Download and install the patched version of Skype 5.5 from here (the patch enables the Skype client to save the logs in non obfuscated form)

2. Save the lines below as a Skype_log_patch.reg reg file:

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Skype\Phone\UI\General]
"LastLanguage"="en"
"Logging"="SkypeDebug2003"
"Logging2"="on"
Once saved, run it to enable the Skype Debug Log File.

4. Start Skype.

5. Search for any Skype contact and click on the 'Add a Skype Contact' button, but do not send the request, rather click on the user to view their VCard.

4. Open the log file (it should appear in the same folder as Skype executable e.g. debug-20121003-0150)

5. Look for the PresenceManager line - you should see something similar to this - >

In the above image you can spot my Skype name, external as well as internal IP addresses.

The log will include similar credentilas for everyone listed as a "contact" under your Skype account, as well as many other fresh, genuine and useful information received directly from your local Skype tracker.

Mon, 10 Sep 2012

44Con: Vulnerability analysis of the .NET smart Card Operating System

Today's smart cards such as banking cards and smart corporate badges are capable of running multiple tiny applications which are often written in high level programming languages like Java or Microsoft .NET and compiled into small card resident binaries. It is a critical security requirement to isolate the execution context and data storage of these applications in order to protect them from unauthorized access by other malicious card applications. To satisfy this requirement, multi-application smart cards implement an “Application Firewall” concept in their operating system which creates an execution sandbox for card applications.

During the recent 44con conference in London, we presented the "HiveMod" reverse engineering tool for .NET smart cards and demonstrated the exploitation of a vulnerability to bypass the card's application firewall. The talk also highlighted threats and possible attack scenarios against smart corporate or military badges.

The presentation slides can be viewed below:

The following video shows exploitation of the "public key token spoofing" vulnerability on the .net smart card using the "HiveMod" tool:

Please contact SensePost research team for more information.