[openssl-users] Question on necessity of SSL_CTX_set_client_CA_list

Kyle Hamilton aerowolf at gmail.com
Fri Dec 7 22:00:53 UTC 2018

CAs *do* verify the attributes they certify.  That they're not presented as
such is not the fault of the CAs, but rather of the browsers who insist on
not changing or improving their UI.

The thing is, if I run a website with a forum that I don't ask for money on
and don't want any transactions happening on, why should I have to pay for
the same level of certainty of my identity that a company like Amazon needs?

(Why does Amazon need that much certainty? Well, I could set up wireless
access points around coffee shops in December, point the DNS provided at
those WAPs to my own server and run a fake amazon.com site to capture
account credentials and credit cards. Without EV, that's a plausible
attack. Especially with SSL being not-by-default, someone could type
amazon.com and it can be intercepted without showing any certificate
warning -- which then allows a redirect to a lookalike amazon.com name that
could get certified by something like LetsEncrypt.)

Plus, clouds have had a protocol available for doing queries to certs and
keys held by other parties for several years. Cloudflare developed this
protocol for banks, for whom loss of control of the certificate key is a
reportable event, but who also often need DDoS protection. There's no
reason it can't be extended to other clouds and sites -- unless Cloudflare
patented it and wants royalties, in which case their rent-seeking is
destroying the security of the web by convincing cloud salesmen to say that
EV is too much trouble to deal with and thus should be killed off in the

Demanding that EV be perfect and dropping support for it if it has any
found vulnerability falls into a class of human behavior known as "letting
the perfect be the enemy of the good", which is also known as "cutting off
the nose to spite the face".  It still cuts down on a huge number of
potential attacks, and doing away with it allows those attacks to flourish
again. (Which, by the way, is what organized crime would prefer to permit.)

-Kyle H

On Thu, Dec 6, 2018, 14:07 Blumenthal, Uri - 0553 - MITLL <uri at ll.mit.edu

> >    > Quoting from Peter Gutmann's "Engineering Security",
> >    > section "EV Certificates: PKI-me-Harder"
> >    >
> >    >      Indeed, cynics would say that this was exactly the problem that
> >    >      certificates and CAs were supposed to solve in the first
> place, and
> >    >      that “high-assurance” certificates are just a way of charging a
> >    >      second time for an existing service.
> >
> >    Peter Gutman, for all his talents, dislikes PKI with a vengeance.
> >     EV is a standard for OV certificates done right.  Which involves more
> >    thorough identity checks, stricter rules for the CAs to follow etc.
> >
> >     The real point of EV certificates is to separate CAs that do a good
> >    job from those that do a more sloppy job, without completely
> distrusting
> >    the mediocre CA operations.
> So, a CA that's supposed to validate its customer before issuing a
> certificate, may do a "more sloppy job" if he doesn't cough up some extra
> money.
> I think Peter is exactly right here. CA either do their job, or they
> don't. If they agree to certify a set of attributes, they ought to verify
> each one of them.
> --
> openssl-users mailing list
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