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Tools released at Defcon can crack widely used PPTP encryption in under a day
CSO ^ | July 29, 2012 | Lucian Constantin

Posted on 07/29/2012 12:52:30 PM PDT by LibWhacker

New tool and service can decrypt any PPTP and WPA2 wireless sessions using MS-CHAPv2 authentication

Security researchers released two tools at the Defcon security conference that can be used to crack the encryption of any PPTP (Point-to-Point Tunneling Protocol) and WPA2-Enterprise (Wireless Protected Access) sessions that use MS-CHAPv2 for authentication.

MS-CHAPv2 is an authentication protocol created by Microsoft and introduced in Windows NT 4.0 SP4. Despite its age, it is still used as the primary authentication mechanism by most PPTP virtual private network (VPN) clients.

MS-CHAPv2 has been known to be vulnerable to dictionary-based brute force attacks since 1999, when a cryptanalysis of the protocol was published by cryptographer Bruce Schneier and other researchers.

However, the common belief on the Internet is that if you have a strong password then it's ok, said Moxie Marlinspike, the security researcher who developed ChapCrack, one of the tools released at Defcon. "What we demonstrated is that it doesn't matter. There's nothing you can do."

ChapCrack can take captured network traffic that contains a MS-CHAPv2 network handshake (PPTP VPN or WPA2 Enterprise handshake) and reduce the handshake's security to a single DES (Data Encryption Standard) key.

This DES key can then be submitted to CloudCracker.com -- a commercial online password cracking service that runs on a special FPGA cracking box developed by David Hulton of Pico Computing -- where it will be decrypted in under a day.

The CloudCracker output can then be used with ChapCrack to decrypt an entire session captured with WireShark or other similar network sniffing tools.

PPTP is commonly used by small and medium-size businesses -- large corporations use other VPN technologies like those provided by Cisco -- and it's also widely used by personal VPN service providers, Marlinspike said.

The researcher gave the example of IPredator, a VPN service from the creators of The Pirate Bay, which is marketed as a solution to evade ISP tracking, but only supports PPTP.

Marlinspike's advice to businesses and VPN providers was to stop using PPTP and switch to other technologies like IPsec or OpenVPN. Companies with wireless network deployments that use WPA2 Enterprise security with MS-CHAPv2 authentication should also switch to an alternative.


TOPICS: Business/Economy; News/Current Events
KEYWORDS: conference; crack; defcon; encryption; pptp; released; security; tools
Don't know a lot about it but heads up if you're still using PPTP at work.
1 posted on 07/29/2012 12:52:44 PM PDT by LibWhacker
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To: LibWhacker

I never assume any form of electronic communication is secure.


2 posted on 07/29/2012 12:57:33 PM PDT by null and void (Day 1286 of our ObamaVacation from reality - Heroes aren't made Frank, they're cornered...)
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To: null and void

For most of us, I think it’s a matter of how much ability someone has and how much effort they’re willing to put into it. With the release of this tool, the effort part of the equation for crackers was just removed.


3 posted on 07/29/2012 1:10:43 PM PDT by LibWhacker
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To: LibWhacker

Since all my servers are Windows 2008 R2, and my clients are running Windows 7, I’ve set SSTP as my standard VPN protocol.

My campus uses Cisco Anywhere Connect, which is OpenSSL, almost the same thing.


4 posted on 07/29/2012 1:13:17 PM PDT by Alas Babylon!
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To: Alas Babylon!

Er, make that Cisco AnyConnect. It is pretty much anywhere!


5 posted on 07/29/2012 1:16:13 PM PDT by Alas Babylon!
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To: LibWhacker
I would assume that anyone who routinely expresses any political thought that doesn't exactly track the party line is regarded by the party as being worthy of extra attention.

How much of the essentially infinite run time of the government computers you get depends on how much you stick up from the herd.

6 posted on 07/29/2012 1:27:07 PM PDT by null and void (Day 1286 of our ObamaVacation from reality - Heroes aren't made Frank, they're cornered...)
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To: LibWhacker

WPA has been hackable for quite a while with free tools. Wireless is not secure.


7 posted on 07/29/2012 1:46:04 PM PDT by driftdiver (I could eat it raw, but why do that when I have a fire.)
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To: driftdiver

802.X with EAP/TLS. Adjust WAP and client signal strength to controlled physical space as much as possible. Limit unauthorized physical access. Classify data into security categories and never use wireless or Internet access on machines handling the more sensitive categories.

Security is an ongoing game.

Assume that all these methods will be broken eventually. Keep evolving!


8 posted on 07/29/2012 2:06:21 PM PDT by Alas Babylon!
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To: null and void
I would assume that anyone who routinely expresses any political thought that doesn't exactly track the party line is regarded by the party as being worthy of extra attention. How much of the essentially infinite run time of the government computers you get depends on how much you stick up from the herd.

Post on Free Republic, and you get on the NSA's rolling smartphone crypto-twitter feed, alongside chemical analysis of your nose hairs.


9 posted on 07/29/2012 2:33:23 PM PDT by Talisker (One who commands, must obey.)
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To: LibWhacker

I keep saying I am going to wire for ethernet and give up my tablet, but it’s like a crack addict trying to stop crack for me, evidently.

I just love being able to surf on my ipod & tablet. Dang it.

I wish infrared had made it big... I could install local infrared access points in each room, and be reasonably secure (there is still the issue of light leakage through windows and such, but it would take professional equipment to access that reliably, and a position which I could easily detect a hacker in).

I think the sum total is this: wireless encryption needs to get A LOT BETTER.

Maybe I will setup a VPN which my wireless devices have to access to get to the internet.


10 posted on 07/29/2012 2:46:32 PM PDT by Aqua225 (Realist)
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To: LibWhacker

I recently implemented an IPSEC host to host capability for a customer. It uses IKE and AES crypto. Both AH and ESP elements. The only down side was network performance is cut in half. Using signed certs for the authentication gives you the ability to lockout unauthorized use bia a CRL.


11 posted on 07/29/2012 3:50:41 PM PDT by Myrddin
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To: Alas Babylon!

We were doing a wireless security scan for a client a few weeks ago. Came across a network labeled ‘USDOJ Surveillance Team’.


12 posted on 07/29/2012 3:51:02 PM PDT by driftdiver (I could eat it raw, but why do that when I have a fire.)
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To: Aqua225

all you have to do is mac-lock your wireless security and it won’t really matter. For home use, it’s really not that much of a pain


13 posted on 07/29/2012 6:36:17 PM PDT by FunkyZero (... I've got a Grand Piano to prop up my mortal remains)
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To: FunkyZero

MAC addresses are really easy to spoof. At least on my OS X box, I can spoof it’s MAC address with a single command on the command line.


14 posted on 07/30/2012 8:01:49 AM PDT by Monitor ("The urge to save humanity is almost always a false-front for the urge to rule it." - H. L. Mencken)
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To: Alas Babylon!

This is what I’ve built for my Network. Working fine so far.


15 posted on 07/30/2012 8:08:08 AM PDT by Dead Corpse (I will not comply.)
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To: Dead Corpse

I live out in the country on multi-acres. Controlling my physical space is easy. Anyone caught trespassing finds themselves in “fields of fire”! Still, I secure my home wireless.

Now I hear on Drudge that Homeland Security will be using drones in the USA. Will that be government sponsored “war-flying”?

Maybe I’ll be skeet shooting on that day.... Oops! Sorry about your model plane, Mister! Honest!

Unless some of you devise a good hack to make them crash... Maybe something on your wireless networks they’re snooping for. Call it a drone takedown honeypot.


16 posted on 07/30/2012 9:50:03 AM PDT by Alas Babylon!
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To: Monitor

I’m aware the MAC is easy to spoof, but you have to know what specific address to spoof in order to do it. That’s a very difficult challenge, near impossible.


17 posted on 07/30/2012 10:18:03 PM PDT by FunkyZero (... I've got a Grand Piano to prop up my mortal remains)
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