Pages

Thursday, December 8, 2016

Dirty Cow



A potential game changer in forensics


All blog posts to date


About two and a half years ago, I wrote a post on live imaging an Android device.  Based on the view stats I see on this blog, it seems like this post has a lot of popularity.

Fast forward some time and several operating system revisions, and the post is now quite obsolete.  The post relied upon TowelRoot, which is an exploit that has been patched for over two years.

Now what is not obsolete is the general method.  Data connection between the forensic computer and the device, exploit, imaging command.  These concepts are still the same.  The problem is, I don't have an exploit for new Android devices.

Dirty Cow
Enter cve-2016-5195, or "Dirty Cow".  The link in the previous sentence is to the official documented exploit.  In short, it is a Linux exploit that is also in the Android kernel.  It could potentially be used as a root vulnerability.




Several developers have released open source versions of Dirty Cow for Android, but all as proof-of-concepts.  To the best of my knowledge, nobody has released a version of Dirty Cow specifically for rooting devices.  I have tried several techniques on my personal phone and still no root shell.  The source is open in C and can be compiled using the Android NDK.  Now I personally have C experience, but the last time C was my primary language, the top selling phone worldwide was the Motorola Razr and Barack Obama was a little known senator from Illinois.  And the world still hated Tom Brady and the Patriots, so I guess some things never change.  Didn't I mention in my previous post that I'm officially a dinosaur?

Implications
If anybody gets Dirty Cow working on Android like Towel Root, meaning a do-all root program, then suddenly we as forensic examiners can use the live imaging guide to image any current Android device, or at least until Dirty Cow is patched and the patch is wide spread.

As I am using a Galaxy S6 running 6.0, I have not rooted my phone.  That may come as a shock to many.  The reason is I do not have a way to root my phone without tripping the Knox warranty bit.  I would like to keep that intact but still gain a root shell.

And of course, where there are forensic implications, there are also security implications.  If I can image anyone's phone, then so can anyone else.  And anyone can access and take privileged information from a device.

Community Work
So here comes the point of this post.  Who out there is working on Dirty Cow or other new exploits?  If anyone reading this is interested in Android forensics and is working on gaining root shells, I'd sure like to hear about it, whether you are using Dirty Cow or something else entirely.  If you are able to, please share.  I am happy to collaborate or point you in the direction of someone who can collaborate as well.

And, have you had any success with Dirty Cow or any other current exploit?  If so, how did you do it, what device, any troubles, etc?

I personally would be very interested in getting an exploit for newer Android phones up and running..  The purpose here is for forensic research so I can share with the digital forensics community community continuing results.

Summary

  • TowelRoot is obsolete.
  • Dirty Cow is a a possible way to gain an equivalent root shell on newer devices.
  • Collaboration?
Questions, comments?  Any research you wish to share?  Leave a comment below, or send me an email.