Moxie MS-CHAPv2 and David Too!
Probably the biggest news at Defcon 20 was Moxie Marlinspike and David Hulton's insight into reliably breaking MS-CHAPv2 100% of the time.
The vulnerability which they leveraged, which was based upon the earlier work of Bruce Schneirer and Mudge in 1999!
So here's the deal. While Bruce, Mudge, Moxie and David are all really, really bright, the SCARY truth is that they aren't the only smart guys on the Internet.
The situation reminds me of when the DES vulnerability was finally confimed to be vulnerable and easily crackable by the guys in the Puzzle Palace, though it had been speculated at for quite some time.
The ramifications and implications are earth-shattering.
Every encrypted PPTP session that has been recorded (in the off chance that Moxie, David or some other bright person on the inntertubez would find out how to break Ms-CHAPv2) can now be read with impunity.
An even SCARIER possibility is that this technique has been known for awhile and those conversations have been read, since ... say 1999!
Major props to Moxie and David for their brilliant work.
To the rest of you, who rely upon PPTP or MS-CHAPv2 in some other aspect of your network security (which is most of us) good luck ;)
As a service to out readers, here is a link to Moxie's discussion of the technique: https://www.cloudcracker.com/blog/2012/07/29/cracking-ms-chap-v2/
Here is a link to Moxie's chapcrack tool https://github.com/moxie0/chapcrack
And here is the link to Cloudcraker to send your tokens to https://www.cloudcracker.com/
Last Updated on Tuesday, 07 August 2012 00:36 Written by DC 406 Webmaster Tuesday, 07 August 2012 00:17