Subject: Re: Software for PKI

From: "Bob Jueneman" <[email-masked]>
Date: Wed, 07 Nov 2001 19:12:22 -0700

That happens to be a particularly interesting point, because it illustrates a fundamental flaw in how SSL is most often used (which is off the topic of PKI, but perhaps relevant).

You went to www.united.com or www.ual.com using an unauthenticated http session (https doesn't work -- they didn't make that page available.)  Therefore you don't really know whether you are connected to United Air Lines or to Untied Air Taliban.  Then if you select say the Request Upgrade option, this untrusted site refers you off to some other site that you never heard of, with a DNS name (https://www.ua2go.com/ci/Login.jsp?return_to=eug_req) that has little if any obvious connection with United Air Lines except for the "ua" prefix (if you bothered to check the certificate).  and that site then asks you to log in, and presumably will get around to asking for your credit card number sooner or later.

And you are supposed to get all warm and fuzzy inside, knowing that your credit card number was encrypted over your gigabit LAN interface that no one could intercept as a practical matter anyway.  Meanwhile, your sacred credit card information is sitting at a site that you never heard of, protected by God knows what form of computer security if any at all, after you were sent there by a site that you had no technically sound reason to trust in the first place!

And oh by the way, I didn't mention the fact that IE didn't allow you to control what algorithms or keys sizes were selected, so you might very well be trusting your data to an outmoded 40-bit algorithm, or (even more insanely) to a Null crypto algorithm!  (You did remember to click on the properties button each time, to see what crypto strength was used, and what the certificate path said?  Sure you did -- every time, too.)

So ubiquitous, almost.  But secure, I'm not so sure. The PKI works, but the result is just window dressing.

But fortunately that's a different IETF group, so we can blame them.

Bob

>>> Peter Gutmann <[email-masked]> 11/07/01 05:08PM >>>

Eric Rescorla <[email-masked]> writes:
[email-masked] (Peter Gutmann) writes:
>>My favourite example: Go to www.united.com and have a look at the cert you
>>get.
>I can't seem to connect to www.united.com:443 

You have to go there with HTTP and then select one of the HTTPS links.

>I assume your point here is that it www.united.com redirects you to
>www.ual.com? If so, I don't see the problem with this. 

You end up (once you're using SSL) talking to a site which is completely
unrelated to United (itn.net) although there's no indication from the browser
that you've ended up talking to who knows what (that is, no warning unless
you've got the appropriate warning option enabled in your browser, if you do
enable it you get so many false alarms you tend to turn it off again fairly
quickly.  Also, the URL is so long you can't see the server name).  As a result
unless you go out of your way to check, it looks like you're talking SSL to
United when it's actually to itn.net.

(The same is true for any virtual hosting and whatnot system, I'm just using
United as an example).

Peter.

---

From: Aram Perez <[email-masked]>
Date: Wed, 07 Nov 2001 23:39:47 -0800

On Wednesday, November 7, 2001, at 06:12  PM, Bob Jueneman wrote:

[snip]
> And you are supposed to get all warm and fuzzy inside, knowing that 
> your credit card number was encrypted over your gigabit LAN interface 
> that no one could intercept as a practical matter anyway.  Meanwhile, 
> your sacred credit card information is sitting at a site that you never 
> heard of, protected by God knows what form of computer security if any 
> at all, after you were sent there by a site that you had no technically 
> sound reason to trust in the first place!
>
Is this any different from handing over my credit card to a total 
stranger at a restaurant?

A basic problem with PKIX is that people equate trust with cryptography. 
Humans do not establish trust based on some mathematic equation.

My dos centavos,
Aram

---

From: Michael Ströder <[email-masked]>
Date: Thu, 08 Nov 2001 11:24:00 +0100

> sound reason to trust in the first place!

You're right. E.g. the biggest european web hoster Strato offers a
pre-configured CGI-BIN which takes a credit card number, validates
it and ....guess what... sends it via unencrypted e-mail to the
owner of the web shop. (sigh!)

Ciao, Michael.