Re: [saag] SHA-1 to SHA-n transition

[Stephen Kent <[e-mail]>]

At
>...
>>  Another vulnerability, and matching MITM attack, is enabled by the
>>  issuance of certs that contain wildcard DNS names. This is not, a
>>  violation of P3, because PKIX caved to pressure from the TLS WG, to
>>  accommodate web site operators who wanted to purchase one cert from a
>>  TTP that could be used to verify the EE certs for multiple web sites.
>>  I argued against this, but lost. The phrase "I told you so" comes to
>>  mind :-).
>
>Can you briefly describe how this leads to MITM attacks? This is something
>I haven't heard before.

Look at the latter half of these slides for his description of the 
role that wildcard DNS names on certs play in one class of attacks.

<https://www.blackhat.com/presentations/bh-dc-09/Marlinspike/BlackHat-DC-09-Marlinspike-Defeating-SSL.pdf>


Steve