Microsoft yesterday warned Windows users of possible "man-in-the-middle" attacks able to steal passwords for some wireless networks and VPNs, or virtual private networks.
It won't issue a security update for the problem, however.
The
security advisory was Microsoft's reaction to a
disclosure several weeks ago by security researcher Moxie Marlinspike at the Defcon conference.
In a
blog post written shortly after his Defcon talk, Marlinspike explained his interest in MS-CHAP v2 (Microsoft Challenge Handshake Authentication Protocol version 2). "Even as an aging protocol with some prevalent criticism, it's still used quite pervasively," Marlinspike said. "It shows up most notably in PPTP VPNs, and is also used quite heavily in WPA2 Enterprise environments."
At the same time, Marlinspike published "Chapcrack," a tool that parses data for passwords encrypted with MS-CHAP v2, then decodes them using the
CloudCracker password cracking service.
