In response to a new threat of attack caused by a flaw in the Secure Socket Layer (SSL) 3.0 and Transport Layer Security (TLS) 1.0, Microsoft has issued Security Advisory 2588513, which contains a description and workarounds.

The flaw, discovered and demonstrated by two security researchers last week, allows for a potential attacker to pull off a man-in-the-middle exploit by gaining access to a user's machine through an active HTTPS session.

Isn't RC4 a weak algorithm??