Friday, November 6, 2009

Zero-day flaw found in web encryption

A zero-day flaw in the TLS and SSL protocols, which are commonly used to encrypt web pages, has been made public.

Security researchers Marsh Ray and Steve Dispensa unveiled the TLS (Transport Layer Security) flaw on Wednesday, following the disclosure of separate, but similar, security findings. TLS and its predecessor, SSL (Secure Sockets Layer), are typically used by online retailers and banks to provide security for web transactions.

Ray, who along with Dispensa works for two-factor authentication company PhoneFactor, explained in a blog post on Thursday that he had initially discovered the flaw in August, and demonstrated a working exploit to Dispensa at the beginning of September.

The flaw in the TLS authentication process allows an outsider to hijack a legitimate user's browser session and successfully impersonate the user, the researchers said in a technical paper.

The fault lies in an "authentication gap" in TLS, Ray and Dispensa said. During the cryptographic authentication process, in which a series of electronic handshakes take place between the client and server, there is a loss of continuity in the authentication of the server to the client. This gives an attacker an opening to hijack the data stream, they said.

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Check also Major SSL Flaw Discovered

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