Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id AB45D80535 for ; Wed, 24 Oct 2007 08:08:52 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id CAAD91421FB for ; Wed, 24 Oct 2007 08:07:57 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -1.692 X-Spam-Level: X-Spam-Status: No, score=-1.692 tagged_above=-50 required=4 tests=[AWL=0.907, BAYES_00=-2.599] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GduI5A6gtdjd for ; Wed, 24 Oct 2007 08:07:49 -0700 (PDT) Received: from brmea-mail-1.sun.com (brmea-mail-1.Sun.COM [192.18.98.31]) by laweleka.osafoundation.org (Postfix) with ESMTP id 6E6B61421F9 for ; Wed, 24 Oct 2007 08:07:49 -0700 (PDT) Received: from dm-central-02.central.sun.com ([129.147.62.5]) by brmea-mail-1.sun.com (8.13.6+Sun/8.12.9) with ESMTP id l9OF7mCG002389 for ; Wed, 24 Oct 2007 15:07:48 GMT Received: from binky.Central.Sun.COM (binky.Central.Sun.COM [129.153.128.104]) by dm-central-02.central.sun.com (8.13.8+Sun/8.13.8/ENSMAIL, v2.2) with ESMTP id l9OF7mwJ062818 for ; Wed, 24 Oct 2007 09:07:48 -0600 (MDT) Received: from binky.Central.Sun.COM (localhost [127.0.0.1]) by binky.Central.Sun.COM (8.14.1+Sun/8.14.1) with ESMTP id l9OF7mLX007219; Wed, 24 Oct 2007 10:07:48 -0500 (CDT) Received: (from nw141292@localhost) by binky.Central.Sun.COM (8.14.1+Sun/8.14.1/Submit) id l9OF7lJ5007218; Wed, 24 Oct 2007 10:07:47 -0500 (CDT) X-Authentication-Warning: binky.Central.Sun.COM: nw141292 set sender to Nicolas.Williams@sun.com using -f Date: Wed, 24 Oct 2007 10:07:47 -0500 From: Nicolas Williams To: christopher@pobox.com Subject: Re: [Ietf-http-auth] Pondering some issues on the phishing draft Message-ID: <20071024150747.GP6776@Sun.COM> References: <79448815.20071024103641@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <79448815.20071024103641@pobox.com> User-Agent: Mutt/1.5.7i Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 15:08:52 -0000 On Wed, Oct 24, 2007 at 10:36:41AM +1000, christopher@pobox.com wrote: > I'd recommend something different; outside the box. If you're worried > about people using UI clues, and you need mutual auth, and you need > per-site security (like pwdhash), it might be best to build all these > in together in a way that users cannot ignore. eg: If PayPal assigned > me a yellow tennis shoe jpeg, and I've got to click that to log in, > that's an elegant small part of the solution that solves all these > problems (and, doesn't need everyone to have admin rights to install > crypto extensions on every PC they use) Phishers want your money. Your passwords are gravy. As long as phishers can mount an MITM attack your scheme fails. Phishing is essentially a MITM attack or built on MITM attacks. You need mutual authentication and end-to-end integrity and (if you want it) confidentiality protection, where the ends are the user agent and the relying party. Some folks are talking about pushing authentication down the stack (e.g., into TLS) to achieve this. Others are talking about pushing integrity and confidentiality protection up the stack (e.g., using S/MIME and to hell with TLS). Still others are talking about channel binding (leaving authentication above TLS and integ/conf protection at the TLS layer and binding the two to prevent MITMs). Any of these solutions could do. But there will be a big UI component -- that little lock icon doesn't cut it. Nico -- Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 7E674804C2 for ; Wed, 24 Oct 2007 07:56:04 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 9DA431421F9 for ; Wed, 24 Oct 2007 07:55:09 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -0.813 X-Spam-Level: X-Spam-Status: No, score=-0.813 tagged_above=-50 required=4 tests=[AWL=0.402, BAYES_00=-2.599, SPF_SOFTFAIL=1.384] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SDLMfZPqilAA for ; Wed, 24 Oct 2007 07:55:03 -0700 (PDT) Received: from carter-zimmerman.suchdamage.org (carter-zimmerman.suchdamage.org [69.25.196.178]) by laweleka.osafoundation.org (Postfix) with ESMTP id 205391421FB for ; Wed, 24 Oct 2007 07:55:02 -0700 (PDT) Received: by carter-zimmerman.suchdamage.org (Postfix, from userid 8042) id BA6834A45; Wed, 24 Oct 2007 10:55:00 -0400 (EDT) From: Sam Hartman To: christopher@pobox.com Subject: Re: [Ietf-http-auth] Pondering some issues on the phishing draft References: <79448815.20071024103641@pobox.com> Date: Wed, 24 Oct 2007 10:55:00 -0400 In-Reply-To: <79448815.20071024103641@pobox.com> (christopher@pobox.com's message of "Wed, 24 Oct 2007 10:36:41 +1000") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ietf-http-auth@lists.osafoundation.org X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 14:56:04 -0000 >>>>> "christopher" == christopher writes: christopher> Hi Sam, I'd recommend something different; outside christopher> the box. If you're worried about people using UI christopher> clues, and you need mutual auth, and you need christopher> per-site security (like pwdhash), it might be best to christopher> build all these in together in a way that users christopher> cannot ignore. eg: If PayPal assigned me a yellow christopher> tennis shoe jpeg, and I've got to click that to log christopher> in, that's an elegant small part of the solution that christopher> solves all these problems (and, doesn't need everyone christopher> to have admin rights to install crypto extensions on christopher> every PC they use) Personally I'm more interested in decreasing the extent to which the document over-sells specific UI solutions rather than thinking more outside the box. I'd appreciate others comments. In particular, I think we can say that strong authentication allows us to provide confidential information to the authenticated user without unacceptable risk that it is being disclosed to the wrong party. So, for example, if you use strong authentication and are using something like sitekey to get mutual authentication, then you would not need to rely on cookies for the image if you sent the sitekey after login. The current document says that this confidential information will help. That's not clear because it's not clear that users will take advantage of the clues. Now, I think it would be appropriate to mention that interacting with confidential components is something to explore. I.E. if it turns out that rather than ignoring the problem, people will tend to call their bank and complain when they cannot find the right shoe to click after they login, then your shoes could abe a part of the answer. Personally I think this is rather unlikely to work. However it is different than sitekey in that you have to make some decision--you have to click something. With sitekey, you can more easily ignore the image. Of course I think the usability concerns of having an extra step in the login process might bother a lot of people. I don't think it would be appropriate to recommend this or really any of the specific UI items as anything other than something to explore. --Sam Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 9CA488058A for ; Wed, 24 Oct 2007 06:44:40 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id BCF251421F9 for ; Wed, 24 Oct 2007 06:43:45 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.448 X-Spam-Level: X-Spam-Status: No, score=-2.448 tagged_above=-50 required=4 tests=[AWL=0.016, BAYES_00=-2.599, FORGED_RCVD_HELO=0.135] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id D9+d7pX+lLZz for ; Wed, 24 Oct 2007 06:43:39 -0700 (PDT) Received: from delta.rtfm.com (unknown [74.95.2.169]) by laweleka.osafoundation.org (Postfix) with ESMTP id 6226E1421EC for ; Wed, 24 Oct 2007 06:43:39 -0700 (PDT) Received: from delta.rtfm.com (localhost.rtfm.com [127.0.0.1]) by delta.rtfm.com (Postfix) with ESMTP id 4F14033C28; Wed, 24 Oct 2007 06:39:14 -0700 (PDT) Date: Wed, 24 Oct 2007 06:39:13 -0700 From: Eric Rescorla To: Chris Drake Subject: Re: Re[6]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <1992079493.20071024230252@pobox.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> <13784696.20071024145013@pobox.com> <20071024050544.A03C033C28@delta.rtfm.com> <444091193.20071024154801@pobox.com> <20071024120306.7099B33C28@delta.rtfm.com> <1992079493.20071024230252@pobox.com> User-Agent: Wanderlust/2.14.0 (Africa) Emacs/21.3 Mule/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Message-Id: <20071024133914.4F14033C28@delta.rtfm.com> Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 13:44:40 -0000 At Wed, 24 Oct 2007 23:02:52 +1000, Chris Drake wrote: > The "game" was a test to see if you're interested in solving the > problem, or have a hidden agenda (networkresonance.com I'd guess?). I have no idea what you're insinuating. It's not any secret what I do for a living, and it's not really related to this kind of sign-on or authentication problem at all. > Yes - there's an elegant solution. The Unix/DOS MD5's of it are > below. If you add constructive contributions (aka - play the game), > I'll send an answer. Sorry, that's not the way things work at IETF. If you have something to contribute, publish it in the open literature. If not, you're just wasting everyone's time. > Cookies do work. Everyone knows it; you - of all people - with CDT - > you know that. Actually, I don't know it. At least one site I deal with regularly seems to lose my cookie and forces me to do challenge questions. As I noted previously, that's a phishing target. Moreover, the available evidence [SDOF07] suggests that people don't in fact check for the presence of secret images, so even if one ignores the cookie loss issue, it's not clear that this technique works. > Adequate recovery is the same as any enrollment > problem, No, again, it's not. Because it happens frequently, it has to be lightweight and automated (challenge questions being the typical thing). -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 4AC33804CA for ; Wed, 24 Oct 2007 06:04:07 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 6A8B31421FC for ; Wed, 24 Oct 2007 06:03:12 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.395 X-Spam-Level: X-Spam-Status: No, score=-2.395 tagged_above=-50 required=4 tests=[AWL=0.205, BAYES_00=-2.599, SPF_HELO_PASS=-0.001] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RRU6pFtGx6l7 for ; Wed, 24 Oct 2007 06:03:00 -0700 (PDT) Received: from srve.com (srve.com [208.69.183.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by laweleka.osafoundation.org (Postfix) with ESMTP id D945A1421FB for ; Wed, 24 Oct 2007 06:02:58 -0700 (PDT) Received: from localhost (www.hunneypocketed.emsvr.com [203.206.137.129] (may be forged)) (authenticated bits=0) by srve.com (8.13.8/8.13.8/CWT/DCE) with ESMTP id l9OD2rQd001695 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO); Wed, 24 Oct 2007 13:02:56 GMT Date: Wed, 24 Oct 2007 23:02:52 +1000 From: Chris Drake X-Priority: 3 (Normal) Message-ID: <1992079493.20071024230252@pobox.com> To: Eric Rescorla Subject: Re[6]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <20071024120306.7099B33C28@delta.rtfm.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> <13784696.20071024145013@pobox.com> <20071024050544.A03C033C28@delta.rtfm.com> <444091193.20071024154801@pobox.com> <20071024120306.7099B33C28@delta.rtfm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 13:04:07 -0000 Hi Eric, The "game" was a test to see if you're interested in solving the problem, or have a hidden agenda (networkresonance.com I'd guess?). Yes - there's an elegant solution. The Unix/DOS MD5's of it are below. If you add constructive contributions (aka - play the game), I'll send an answer. Meanwhile, others are invited to ask off-list for the solution, if they like. Cookies do work. Everyone knows it; you - of all people - with CDT - you know that. Adequate recovery is the same as any enrollment problem, not that it's relevant 99.9% of the time (I already said cookies aren't the answer btw.). Kind Regards, Chris Drake Wednesday, October 24, 2007, 10:03:06 PM, you wrote: ER> At Wed, 24 Oct 2007 15:48:01 +1000, ER> christopher@pobox.com wrote: >> >> Hi Eric, >> >> Cookies work, yes ER> No, cookies don't work. ER> The problem, as I said, is that any mechanism which relies on cookies ER> needs a recovery mechanism in case the cookie gets lost. That recovery ER> mechanism generally entails a bunch of challenge questions. But ER> now those challenge questions themselves become a phishing target. >> - so you answered your own question for 99.9% of use >> cases (the remaining 0.1% being folks who regularly use machines they >> can't store their cookies on). You also highlighted the drawbacks of >> pwdhash - how does a user do anything on the theoretical "new device", >> especially one like a phone or work PC that has no plugin or admin >> rights? >> Anyhow - while cookies work - that's still boringly "inside the box" >> and assuming far too much. Here's the MD5s of my next reply to you: >> 1134102756cd5c895709aeb9d821b4da 82b4f03e38fc086ade8d35a4a743c7b9 >> >> Have a go at lateral-thinking, jump outside the box, and let me know >> what better ideas you can come up with besides cookies. Hint: >> challenge *all* your assumptions :-) ER> How about instead we skip the game playing and you describe what ER> you have in mind? ER> -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id D0C9F8056C for ; Wed, 24 Oct 2007 05:08:32 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id F09DF142209 for ; Wed, 24 Oct 2007 05:07:37 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.447 X-Spam-Level: X-Spam-Status: No, score=-2.447 tagged_above=-50 required=4 tests=[AWL=0.017, BAYES_00=-2.599, FORGED_RCVD_HELO=0.135] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8ugL1k7TyekM for ; Wed, 24 Oct 2007 05:07:31 -0700 (PDT) Received: from delta.rtfm.com (unknown [74.95.2.169]) by laweleka.osafoundation.org (Postfix) with ESMTP id BE4141421FF for ; Wed, 24 Oct 2007 05:07:31 -0700 (PDT) Received: from delta.rtfm.com (localhost.rtfm.com [127.0.0.1]) by delta.rtfm.com (Postfix) with ESMTP id 7099B33C28; Wed, 24 Oct 2007 05:03:06 -0700 (PDT) Date: Wed, 24 Oct 2007 05:03:06 -0700 From: Eric Rescorla To: christopher@pobox.com Subject: Re: Re[4]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <444091193.20071024154801@pobox.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> <13784696.20071024145013@pobox.com> <20071024050544.A03C033C28@delta.rtfm.com> <444091193.20071024154801@pobox.com> User-Agent: Wanderlust/2.14.0 (Africa) Emacs/21.3 Mule/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Message-Id: <20071024120306.7099B33C28@delta.rtfm.com> Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 12:08:32 -0000 At Wed, 24 Oct 2007 15:48:01 +1000, christopher@pobox.com wrote: > > Hi Eric, > > Cookies work, yes No, cookies don't work. The problem, as I said, is that any mechanism which relies on cookies needs a recovery mechanism in case the cookie gets lost. That recovery mechanism generally entails a bunch of challenge questions. But now those challenge questions themselves become a phishing target. > - so you answered your own question for 99.9% of use > cases (the remaining 0.1% being folks who regularly use machines they > can't store their cookies on). You also highlighted the drawbacks of > pwdhash - how does a user do anything on the theoretical "new device", > especially one like a phone or work PC that has no plugin or admin > rights? > Anyhow - while cookies work - that's still boringly "inside the box" > and assuming far too much. Here's the MD5s of my next reply to you: > 1134102756cd5c895709aeb9d821b4da 82b4f03e38fc086ade8d35a4a743c7b9 > > Have a go at lateral-thinking, jump outside the box, and let me know > what better ideas you can come up with besides cookies. Hint: > challenge *all* your assumptions :-) How about instead we skip the game playing and you describe what you have in mind? -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 98BAE8058A for ; Tue, 23 Oct 2007 22:49:14 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id BC7311421FB for ; Tue, 23 Oct 2007 22:48:19 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -1.95 X-Spam-Level: X-Spam-Status: No, score=-1.95 tagged_above=-50 required=4 tests=[AWL=-0.310, BAYES_00=-2.599, NO_REAL_NAME=0.961, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Xq83yy13cB24 for ; Tue, 23 Oct 2007 22:48:09 -0700 (PDT) Received: from srve.com (srve.com [208.69.183.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by laweleka.osafoundation.org (Postfix) with ESMTP id E96EC1421FD for ; Tue, 23 Oct 2007 22:48:07 -0700 (PDT) Received: from localhost (www.hunneypocketed.emsvr.com [203.206.137.129] (may be forged)) (authenticated bits=0) by srve.com (8.13.8/8.13.8/CWT/DCE) with ESMTP id l9O5m1rB028923 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO); Wed, 24 Oct 2007 05:48:05 GMT Date: Wed, 24 Oct 2007 15:48:01 +1000 From: christopher@pobox.com X-Priority: 3 (Normal) Message-ID: <444091193.20071024154801@pobox.com> To: Eric Rescorla Subject: Re[4]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <20071024050544.A03C033C28@delta.rtfm.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> <13784696.20071024145013@pobox.com> <20071024050544.A03C033C28@delta.rtfm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 05:49:14 -0000 Hi Eric, Cookies work, yes - so you answered your own question for 99.9% of use cases (the remaining 0.1% being folks who regularly use machines they can't store their cookies on). You also highlighted the drawbacks of pwdhash - how does a user do anything on the theoretical "new device", especially one like a phone or work PC that has no plugin or admin rights? Anyhow - while cookies work - that's still boringly "inside the box" and assuming far too much. Here's the MD5s of my next reply to you: 1134102756cd5c895709aeb9d821b4da 82b4f03e38fc086ade8d35a4a743c7b9 Have a go at lateral-thinking, jump outside the box, and let me know what better ideas you can come up with besides cookies. Hint: challenge *all* your assumptions :-) Chris Wednesday, October 24, 2007, 3:05:43 PM, you wrote: ER> At Wed, 24 Oct 2007 14:50:13 +1000, ER> christopher@pobox.com wrote: >> >> Hi Eric, >> >> The shoe's the mutual auth - if it's wrong or missing, you're being >> phished. When present, you've subtly compelled users to use the >> "clue", which was Sam's other big worry. ER> And what stops the attacker from entering your userid and seeing the ER> same picture? In the past, when I've seen systems like this, the ER> client stores some cookie which tells the server which picture to ER> show. But when the user uses a new device, or the client forgets the ER> cookie, they get prompted with some extended authentication ER> dialog---which is a good candidate for phishing. And since due to ER> various glitches this happens somewhat frequently... ER> -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 07C7980A30 for ; Tue, 23 Oct 2007 22:11:11 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 2BCC2142201 for ; Tue, 23 Oct 2007 22:10:16 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.447 X-Spam-Level: X-Spam-Status: No, score=-2.447 tagged_above=-50 required=4 tests=[AWL=0.017, BAYES_00=-2.599, FORGED_RCVD_HELO=0.135] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pH6IsUwgTx0f for ; Tue, 23 Oct 2007 22:10:10 -0700 (PDT) Received: from delta.rtfm.com (unknown [74.95.2.169]) by laweleka.osafoundation.org (Postfix) with ESMTP id 1782B1421FC for ; Tue, 23 Oct 2007 22:10:09 -0700 (PDT) Received: from delta.rtfm.com (localhost.rtfm.com [127.0.0.1]) by delta.rtfm.com (Postfix) with ESMTP id A03C033C28; Tue, 23 Oct 2007 22:05:44 -0700 (PDT) Date: Tue, 23 Oct 2007 22:05:43 -0700 From: Eric Rescorla To: christopher@pobox.com Subject: Re: Re[2]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <13784696.20071024145013@pobox.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> <13784696.20071024145013@pobox.com> User-Agent: Wanderlust/2.14.0 (Africa) Emacs/21.3 Mule/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Message-Id: <20071024050544.A03C033C28@delta.rtfm.com> Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 05:11:11 -0000 At Wed, 24 Oct 2007 14:50:13 +1000, christopher@pobox.com wrote: > > Hi Eric, > > The shoe's the mutual auth - if it's wrong or missing, you're being > phished. When present, you've subtly compelled users to use the > "clue", which was Sam's other big worry. And what stops the attacker from entering your userid and seeing the same picture? In the past, when I've seen systems like this, the client stores some cookie which tells the server which picture to show. But when the user uses a new device, or the client forgets the cookie, they get prompted with some extended authentication dialog---which is a good candidate for phishing. And since due to various glitches this happens somewhat frequently... -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 7CC45808BE for ; Tue, 23 Oct 2007 21:51:28 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 9524D1421FB for ; Tue, 23 Oct 2007 21:50:33 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -1.994 X-Spam-Level: X-Spam-Status: No, score=-1.994 tagged_above=-50 required=4 tests=[AWL=-0.355, BAYES_00=-2.599, NO_REAL_NAME=0.961, SPF_HELO_PASS=-0.001] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GCs0oGFheMS9 for ; Tue, 23 Oct 2007 21:50:22 -0700 (PDT) Received: from srve.com (srve.com [208.69.183.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by laweleka.osafoundation.org (Postfix) with ESMTP id 97CF71421F9 for ; Tue, 23 Oct 2007 21:50:22 -0700 (PDT) Received: from localhost (www.hunneypocketed.emsvr.com [203.206.137.129] (may be forged)) (authenticated bits=0) by srve.com (8.13.8/8.13.8/CWT/DCE) with ESMTP id l9O4oFT1028394 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO); Wed, 24 Oct 2007 04:50:19 GMT Date: Wed, 24 Oct 2007 14:50:13 +1000 From: christopher@pobox.com X-Priority: 3 (Normal) Message-ID: <13784696.20071024145013@pobox.com> To: Eric Rescorla Subject: Re[2]: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <20071024041033.7338533C28@delta.rtfm.com> References: <79448815.20071024103641@pobox.com> <20071024041033.7338533C28@delta.rtfm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 04:51:30 -0000 Hi Eric, The shoe's the mutual auth - if it's wrong or missing, you're being phished. When present, you've subtly compelled users to use the "clue", which was Sam's other big worry. This is just the phishing resistant and mutual authentication parts: an implementation has more stuff before (eg: enrollment, SSL), after (eg: DoS avoidance, failure reporting,...), and "in the middle" (eg: optional tokens, biometrics, audio alternatives for the blind,...) Chris Wednesday, October 24, 2007, 2:10:32 PM, you wrote: ER> At Wed, 24 Oct 2007 10:36:41 +1000, ER> christopher@pobox.com wrote: >> I'd recommend something different; outside the box. If you're worried >> about people using UI clues, and you need mutual auth, and you need >> per-site security (like pwdhash), it might be best to build all these >> in together in a way that users cannot ignore. eg: If PayPal assigned >> me a yellow tennis shoe jpeg, and I've got to click that to log in, >> that's an elegant small part of the solution that solves all these >> problems (and, doesn't need everyone to have admin rights to install >> crypto extensions on every PC they use) ER> Hmm... ER> Could you explain in more detail how this works and why it's ER> phishing resistant? ER> -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 8D07380A30 for ; Tue, 23 Oct 2007 21:16:02 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 315EF142209 for ; Tue, 23 Oct 2007 21:15:05 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.447 X-Spam-Level: X-Spam-Status: No, score=-2.447 tagged_above=-50 required=4 tests=[AWL=0.017, BAYES_00=-2.599, FORGED_RCVD_HELO=0.135] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kVWjTBsITWwc for ; Tue, 23 Oct 2007 21:14:59 -0700 (PDT) Received: from delta.rtfm.com (unknown [74.95.2.169]) by laweleka.osafoundation.org (Postfix) with ESMTP id 0F86E142207 for ; Tue, 23 Oct 2007 21:14:59 -0700 (PDT) Received: from delta.rtfm.com (localhost.rtfm.com [127.0.0.1]) by delta.rtfm.com (Postfix) with ESMTP id 7338533C28; Tue, 23 Oct 2007 21:10:33 -0700 (PDT) Date: Tue, 23 Oct 2007 21:10:32 -0700 From: Eric Rescorla To: christopher@pobox.com Subject: Re: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: <79448815.20071024103641@pobox.com> References: <79448815.20071024103641@pobox.com> User-Agent: Wanderlust/2.14.0 (Africa) Emacs/21.3 Mule/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Message-Id: <20071024041033.7338533C28@delta.rtfm.com> Cc: ietf-http-auth@lists.osafoundation.org, Sam Hartman X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 04:16:02 -0000 At Wed, 24 Oct 2007 10:36:41 +1000, christopher@pobox.com wrote: > I'd recommend something different; outside the box. If you're worried > about people using UI clues, and you need mutual auth, and you need > per-site security (like pwdhash), it might be best to build all these > in together in a way that users cannot ignore. eg: If PayPal assigned > me a yellow tennis shoe jpeg, and I've got to click that to log in, > that's an elegant small part of the solution that solves all these > problems (and, doesn't need everyone to have admin rights to install > crypto extensions on every PC they use) Hmm... Could you explain in more detail how this works and why it's phishing resistant? -Ekr Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 44CA280AD8 for ; Tue, 23 Oct 2007 17:37:42 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 3EE9214220A for ; Tue, 23 Oct 2007 17:36:47 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -2.053 X-Spam-Level: X-Spam-Status: No, score=-2.053 tagged_above=-50 required=4 tests=[AWL=-0.413, BAYES_00=-2.599, NO_REAL_NAME=0.961, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WA+4t4OPT97v for ; Tue, 23 Oct 2007 17:36:37 -0700 (PDT) Received: from srve.com (srve.com [208.69.183.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by laweleka.osafoundation.org (Postfix) with ESMTP id 2BE5E142201 for ; Tue, 23 Oct 2007 17:36:34 -0700 (PDT) Received: from localhost (www.hunneypocketed.emsvr.com [203.206.137.129] (may be forged)) (authenticated bits=0) by srve.com (8.13.8/8.13.8/CWT/DCE) with ESMTP id l9O0aUm7025016 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO); Wed, 24 Oct 2007 00:36:33 GMT Date: Wed, 24 Oct 2007 10:36:41 +1000 From: christopher@pobox.com X-Priority: 3 (Normal) Message-ID: <79448815.20071024103641@pobox.com> To: Sam Hartman Subject: Re: [Ietf-http-auth] Pondering some issues on the phishing draft In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ietf-http-auth@lists.osafoundation.org X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 00:37:42 -0000 Hi Sam, I'd recommend something different; outside the box. If you're worried about people using UI clues, and you need mutual auth, and you need per-site security (like pwdhash), it might be best to build all these in together in a way that users cannot ignore. eg: If PayPal assigned me a yellow tennis shoe jpeg, and I've got to click that to log in, that's an elegant small part of the solution that solves all these problems (and, doesn't need everyone to have admin rights to install crypto extensions on every PC they use) Chris Wednesday, October 24, 2007, 5:43:30 AM, you wrote: SH> Hi, folks. SH> I wanted to let you know where I am and to solicit some comments. SH> I've been pondering two big issues that came up in ekr's review. SH> The first is pwdhash. Eric correctly points out that the requirements SH> for mutual authentication rule out pwdhash. I don't justify this; SH> Eric says that's a problem and he's right. SH> It's a bit complicated. I'm quite sure that pwdhash is an improvement SH> over what we have today. However I'm also quite sure that it is SH> worthwhile to actually go as far as mutual authentication. So, I SH> don't want to discourage people from deploying something like pwdhash SH> instead of keeping with the status quo. But I also think it is SH> valuable to actually get as far as mutual authentication. I think we SH> should recommend developing authentication systems that meet that SH> goal. However I don't have a coherent justification to propose for SH> your review. I need to come up with that. I've been working on that. SH> I also need to work on text to make it clear that schemes SH> like pwdhash are an improvement. SH> The second issue is response to whether people will actually take SH> advantage of UI clues. I'm also pondering what to say here. SH> _______________________________________________ SH> Ietf-http-auth mailing list SH> Ietf-http-auth@osafoundation.org SH> http://lists.osafoundation.org/cgi-bin/mailman/listinfo/ietf-http-auth Return-Path: X-Original-To: ietf-http-auth@lists.osafoundation.org Delivered-To: ietf-http-auth@lists.osafoundation.org Received: from laweleka.osafoundation.org (laweleka.osafoundation.org [204.152.186.98]) by leilani.osafoundation.org (Postfix) with ESMTP id 013A5809AD for ; Tue, 23 Oct 2007 12:44:38 -0700 (PDT) Received: from localhost (laweleka.osafoundation.org [127.0.0.1]) by laweleka.osafoundation.org (Postfix) with ESMTP id 3B3C31421F9 for ; Tue, 23 Oct 2007 12:43:43 -0700 (PDT) X-Virus-Scanned: by amavisd-new and clamav at osafoundation.org X-Spam-Score: -0.997 X-Spam-Level: X-Spam-Status: No, score=-0.997 tagged_above=-50 required=4 tests=[AWL=0.083, BAYES_00=-2.599, FORGED_RCVD_HELO=0.135, SPF_SOFTFAIL=1.384] Received: from laweleka.osafoundation.org ([127.0.0.1]) by localhost (laweleka.osafoundation.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Vx7GGDXEkiOv for ; Tue, 23 Oct 2007 12:43:37 -0700 (PDT) Received: from carter-zimmerman.suchdamage.org (STRATTON-TWO-SIXTY-SIX.MIT.EDU [18.187.6.11]) by laweleka.osafoundation.org (Postfix) with ESMTP id E9CDA1421F1 for ; Tue, 23 Oct 2007 12:43:36 -0700 (PDT) Received: by carter-zimmerman.suchdamage.org (Postfix, from userid 8042) id BFF124A45; Tue, 23 Oct 2007 15:43:30 -0400 (EDT) From: Sam Hartman To: ietf-http-auth@lists.osafoundation.org Date: Tue, 23 Oct 2007 15:43:30 -0400 Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: [Ietf-http-auth] Pondering some issues on the phishing draft X-BeenThere: ietf-http-auth@osafoundation.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ietf-http-auth.osafoundation.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 Oct 2007 19:44:38 -0000 Hi, folks. I wanted to let you know where I am and to solicit some comments. I've been pondering two big issues that came up in ekr's review. The first is pwdhash. Eric correctly points out that the requirements for mutual authentication rule out pwdhash. I don't justify this; Eric says that's a problem and he's right. It's a bit complicated. I'm quite sure that pwdhash is an improvement over what we have today. However I'm also quite sure that it is worthwhile to actually go as far as mutual authentication. So, I don't want to discourage people from deploying something like pwdhash instead of keeping with the status quo. But I also think it is valuable to actually get as far as mutual authentication. I think we should recommend developing authentication systems that meet that goal. However I don't have a coherent justification to propose for your review. I need to come up with that. I've been working on that. I also need to work on text to make it clear that schemes like pwdhash are an improvement. The second issue is response to whether people will actually take advantage of UI clues. I'm also pondering what to say here.