I think he is. In order to pull off your attack, you need to convince a CA that you have their identity, so you can bind an arbitrary public key to it, then publish it.
But if you can attach an arbitrary public key to someone else's identity, you're going to use that for MITM and not the DoS you described. Which is far worse. -Tim > -----Original Message----- > From: TLS <[email protected]> On Behalf Of Blumenthal, Uri - 0553 - > MITLL > Sent: Friday, October 7, 2022 3:04 PM > To: [email protected] > Subject: Re: [TLS] [lamps] [EXTERNAL] Re: Q: Creating CSR for encryption- > only cert? > > Victor, actually, I take it back - you may be right in that last point. Need > to > think. > > Regards, > Uri > > > On Oct 7, 2022, at 14:59, Blumenthal, Uri - 0553 - MITLL <[email protected]> > wrote: > > > > > >>> On Oct 7, 2022, at 14:42, Viktor Dukhovni <[email protected]> > wrote: > >>> > >>> On Fri, Oct 07, 2022 at 06:19:15PM +0000, Blumenthal, Uri - 0553 - MITLL > wrote: > >>> > >>> Then publish the certificate. Then the victim is unable to read > >>> email encrypted to her. A DoS that costs the attacker very little, > >>> practically nothing. > >> > >> What victim is that? > > > > Person or organization, whose credentials and email address were in the > bogus/modified CSR. > > > >> All the PoP does is make it harder to convince your CA to attest that > >> someone else's key is yours. It plays no role in the most critical > >> role of your CA, which is to not attest that your key is someone else's. > > > > Concur with both points above. > > > >> The scenario you suggest seems to me to require the latter. > > > > I don’t think so. > > > > > > > >> Viktor. > >> > >> _______________________________________________ > >> TLS mailing list > >> [email protected] > >> https://www.ietf.org/mailman/listinfo/tls > > _______________________________________________ > > TLS mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/tls _______________________________________________ TLS mailing list [email protected] https://www.ietf.org/mailman/listinfo/tls
