[telecom] Attack against Microsoft scheme puts hundreds of crypto apps at risk

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Attack against Microsoft scheme puts hundreds of crypto apps at risk Cloud-based service requires an average of 12 hours to decrypt VPN traffic.

by Dan Goodin July 31 2012 Ars Technica

Researchers have devised an attack against a Microsoft-developed authentication scheme that makes it trivial to break the encryption used by hundreds of anonymity and security services, including the iPredator virtual private network offered to users of The Pirate Bay.

The attack, unveiled by Moxie Marlinspike and David Hulton, takes on average just 12 hours to recover the secret key that iPredator and more than 100 other VPN and wireless products use to encrypt sensitive data. The technique, which has been folded into Marlinspike's CloudCracker service, exploits weaknesses in version 2 of a Microsoft technology known as MS-CHAP, short for Microsoft challenge-handshake authentication protocol. It's widely used to log users into VPN and WPA2 networks and is built into a variety of operating systems, including Windows and Ubuntu.

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