W3C home > Mailing lists > Public > public-iri@w3.org > November 2009

Re: phishing in IRIs

From: Mark Davis ☕ <mark@macchiato.com>
Date: Wed, 25 Nov 2009 07:55:12 -0800
Message-ID: <30b660a20911250755ic0990c5x86219df673c615f2@mail.gmail.com>
To: Martin J. Dürst <duerst@it.aoyama.ac.jp>
Cc: Shawn Steele <Shawn.Steele@microsoft.com>, Larry Masinter <masinter@adobe.com>, "PUBLIC-IRI@W3.ORG" <PUBLIC-IRI@w3.org>, Pete Resnick <presnick@qualcomm.com>, Ted Hardie <ted.ietf@gmail.com>, Stephane Bortzmeyer <bortzmeyer@nic.fr>
> What I am saying is that spoofing of IRIs with the domain name part is a
much greater problem than spoofing with IRIs in the rest of the IRI.

Agreed, but even that statement doesn't really convey the relative frequency
of problems. In terms of spoofs:

   1. In the vast majority of the cases, people just don't look at IRIs at
   2. In the vast majority of the remainder, average people don't understand
   the syntax enough to find problems -- *and can't be expected to*. (
   http://safe-wellsfargo.com, or http://secure.ru/amazon.com, or the other
   examples Shawn gave, or the papers found on Stephane's posting)
   3. In a relatively small number of cases there are problems with visually
   confusables... and a smaller number yet of those with IDNs: spoofs with "rn"
   vs "m" are much more common than those with Cyrillic 'a', and those are much
   more common than esoteric symbols.


On Wed, Nov 25, 2009 at 02:25, "Martin J. Dürst" <duerst@it.aoyama.ac.jp>wrote:

> Hello Shawn,
> On 2009/11/25 4:44, Shawn Steele wrote:
>> We're getting WAY off topic.
> I agree.
>  Is there a BCP for IRI security?
> No. The IETF has a tradition of putting security considerations in the main
> document, not as a separate document.
>  So trying to spoof the path is indeed another technique, but in most
>>> cases, it doesn't work because there is a single authority in control of
>>> all the paths on the same domain. So that's why I'm saying that the main
>>> place where spoofing can happen in IRIs is the IDN part.
>> But that only works for you because you know how paths work!
> Yes. I don't think we actually disagree.
> What you are saying is that spoofing because people don't look at IRIs/URIs
> at all is a much greater problem than spoofing with lookalikes and the like.
> I fully agree.
> What I am saying is that spoofing of IRIs with the domain name part is a
> much greater problem than spoofing with IRIs in the rest of the IRI.
> Overall, it's like you saying that one kilometer is bigger than one meter,
> and me saying that one millimeter is greater than one micrometer.
> (sorry I don't have a non-metric equivalent for these examples)
> Regards,    Martin.
>  It's been pretty well demonstrated that the average user doesn't know
>> those things, and, indeed, LEGITIMATE businesses even (mis?)use the system
>> for their convenience or to outsource ads or mail lists or whatnot.
>> Those of us with kids in this country are likely to know about a place
>> called "Check E Cheese's".  And it's a lot cheaper with a coupon.  If I
>> visit http://www.chuckecheese.com/, then I'll have the opportunity to
>> subscribe to an email list and get spammed with coupons periodically.  Those
>> coupons are sent from "Chuck E. Cheese's [
>> cecmail@replies.cecentertainment.com]".  There's absolutely no way to
>> verify that these are connected.  Ruby's is worse.  Rubys.com sends mail
>> from rubys.fbmta.com with links to the same (rubys.fbmta.com).
>>  Toysrus.com gets you to toyrus.shoplocal.com.   I've also seen them in
>> the form client.adfirm.com or adfirm.com/client, no clue if the
>> client/adfirm relationship is legitimate.  Lots of online stores use a 3rd
>> party for checkout.  At least I can recognize yahoo or paypal, but for
>> others I'd have to make a leap of faith.
>> Heck, I got an internal survey about Microsoft which some team had
>> contracted out to an external vendor.  No clue if it was a legitimate
>> internal survey or someone phishing for intelligence about Microsoft.  The
>> mail didn't even come from an internal address.  (Yea, I contacted the group
>> to find out if it was legit, but they were surprised I even bothered).
>> Do you ever follow those links?  I often do.  Of course if it's a bank or
>> its going to end up asking for payment or other info I usually end up
>> retyping the original URL (toysrus.com instead of toysrus.shoplocal.com)
>> and follow links from there, but would the average person bother?
>> When users are trained that any sort of weird variation in the URL is OK,
>> so long as it says my vendor in their somewhere, then there's not much we
>> can do about it, and IDN is completely irrelevant so far as changing
>> security goes.
>> I used to try to contact marketing departments when I noticed that they
>> sent customers to URLs that weren't obviously in their control, but they
>> don't seem to care.  Until that's fixed IDN homographs don't even come close
>> to being interesting.  I don't even think we can fix it because clearly they
>> don't seem to care enough to follow a BCP for IRIs even if one existed.  If
>> I can't even get Microsoft security to be interested in this problem, how do
>> we expect every retailer to bother?
>> Note that in every one of these cases the domain could've been fixed.
>>  Instead of toysrus.shoplocal.com, there's no reason they couldn't have
>> pointed shoplocal.toysus.com to their vendor's server and used that
>> instead.  Similarly the mail could be from vendor.client.com.  My
>> internal survey could've redirected from a trusted internal server to the
>> external one.
>> -Shawn
> --
> #-# Martin J. Dürst, Professor, Aoyama Gakuin University
> #-# http://www.sw.it.aoyama.ac.jp   mailto:duerst@it.aoyama.ac.jp
Received on Wednesday, 25 November 2009 15:55:53 UTC

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