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Researcher Ben Laurie has posted a note on his blog “Links — Ben Laurie blathering” alerting the world to a man-in-the-middle attack against Secure Socket Layer.

“In short, a man-in-the-middle can use SSL renegotiation to inject an arbitrary prefix into any SSL session, undetected by either end,” he wrote

Laurie said he and fellow researchers have a patch to SSL that bans renegotiation.

Blog post here.

Patch here.

Tom Kelchner


“It’s a protocol-level flaw,” Chris Paget, chief technology officer at H4rdw4r

Computer World story “Scramble on to fix flaw in SSL security protocol” here.

Update 2

It never rains but it pours. Transport Layer Security has the problem too:

“Transport Layer Security (TLS, RFC 5246 and previous, including SSL v3 and previous) is subject to a number of serious man-in-the-middle (MITM) attacks related to renegotiation. In general, these problems allow an MITM to inject an arbitrary amount of chosen plaintext into the beginning of the application protocol stream, leading to a variety of abuse possibilities.”

This was blogged by security researchers Marsh Ray and Steve Dispensa today. They work for PhoneFactor , a two-factor authentication company.

TLS and SSL are widely used by online retailers and banks for secure web transactions.

Ray and Dispensa findings here.