> SSL/TLS plus good authentication methods is immune to MITM attacks.[1]
>
> [1] Depending on everyone you trust being trustworthy. What if I'm
> a verisign employee and can manage to generate a verisign-signed
> cert for www.microsoft.com? I can MITM, and no alerts will occur
> until/unless they figure out what happened and revoke my
> certificate, which requires that CRL checking is available in
> the client application you're using.
You can score a technical victory over this MITM attack just by saying that
if you choose to trust a Verisign cert, Verisign is an intended recipient of
the communication. A MITM is not permitted access to anything known only to
intended recipients, and that would include Verisign's private key.
However, most people don't like to think of Verisign as the intended
recipient to all of their HTTPS communication. But technically, if you
choose to trust Verisign certificates, you must either consider Verisign an
intended recipient or you're technically vulnerable to a MITM attack where
the MITM obtains a certificate with the intended server's name in it.
How practical this attack is -- that's another story. Presumably, the
reason you trust Verisign is because such an attack is highly impractical.
DS
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