Secunia

Massimiliano Montoro has reported a security issue in Microsoft Windows, which can be exploited by malicious people to conduct MitM (Man-in-the-Middle) attacks.

The problem is that the private key used for signing a terminal server's public key is hard-coded into the mstlsapi.dll library. This can be exploited to calculate a valid signature, which can be used for performing MitM attacks.

Successful exploitation requires that a malicious person is able to intercept traffic between the terminal client and terminal server.

NOTE: Functionality for exploiting this has reportedly been included in Cain & Abel 2.7.

Solution
Connect only to terminal services over trusted networks.

Provided and/or discovered by
Massimiliano Montoro

Original Advisory
Massimiliano Montoro:
http://www.oxid.it/downloads/rdp-gbu.pdf

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