Re: [TLS] Rizzo claims implementation attach, should be interesting
Martin Rex <mrex@sap.com> Wed, 21 September 2011 01:40 UTC
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From: Martin Rex <mrex@sap.com>
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To: mrex@sap.com
Date: Wed, 21 Sep 2011 03:42:22 +0200
In-Reply-To: <201109202314.p8KNERej029946@fs4113.wdf.sap.corp> from "Martin Rex" at Sep 21, 11 01:14:27 am
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Cc: asteingruebl@paypal-inc.com, geoffk@geoffk.org, tls@ietf.org
Subject: Re: [TLS] Rizzo claims implementation attach, should be interesting
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Martin Rex wrote: > > Geoffrey Keating wrote: > > > > Martin Rex <mrex@sap.com> writes: > > > > > SSL was NEVER designed with a promise that you could multiplex > > > data from an evil attack with data from a victim over the very same > > > SSL connection and be secure against adaptive chose plaintext > > > attacks trying to recover data from the victim. > > > > This would imply that you should not use SSL for downloading e-mail > > using POP or IMAP, because that's multiplexing evil data (mail sent to > > you by the attacker) with trusted data (credentials and non-evil > > mail). > > You are quite correct in recognizing that you might be helping > the attacker in a known-plaintext or chosen-plaintext attack (and when > you have an automatically polling IMAP client, maybe even an adaptive > chosen-plaintext attack). So it would be sensible to limit the number > of guesses for the attacker, and to not re-use the same crypto keys > on subsequent accesses to the same IMAP server (TLS does the latter for > you when you create a new TLS connection state for each subsequent access, > i.e. TLS session resume or full handshake, both will do). Ooops -- what I forgot: Your IMAP cleartext logon password travels Client->Server and the attackers EMail on download travels Server->Client. Since TLS uses distinct traffic encryption and mac keys for both directions, there is no chosen plaintext or adaptive chosen plaintext attack for the particular situation of IMAP Email download, I believe. But that would also suggest that BEAST is not attacking the Cookie from the Server response, but instead the cookie from a client request. (If the browser automatically inserts the cookie into arbitrary requests issued by the attackers malware, then this would mean that a serious Cross-Site-Request-Forgery problem in the browser is a prerequisite for the BEAST attack to succeed. -Martin
- Re: [TLS] Rizzo claims implementation attach, sho… David Wagner
- [TLS] Rizzo claims implementation attach, should … Tim Dierks
- Re: [TLS] Rizzo claims implementation attach, sho… Peter Gutmann
- Re: [TLS] Rizzo claims implementation attach, sho… =JeffH
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Steingruebl, Andy
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Marsh Ray
- Re: [TLS] Rizzo claims implementation attach, sho… Eric Rescorla
- Re: [TLS] Rizzo claims implementation attach, sho… Eric Rescorla
- Re: [TLS] Rizzo claims implementation attach, sho… Yoav Nir
- Re: [TLS] Rizzo claims implementation attach, sho… Marsh Ray
- Re: [TLS] Rizzo claims implementation attach, sho… Yoav Nir
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Marsh Ray
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Eric Rescorla
- Re: [TLS] Rizzo claims implementation attach, sho… Phillip Hallam-Baker
- Re: [TLS] Rizzo claims implementation attach, sho… Nico Williams
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Marsh Ray
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Geoffrey Keating
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… =JeffH
- Re: [TLS] Rizzo claims implementation attach, sho… Nico Williams
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Nico Williams
- Re: [TLS] Rizzo claims implementation attach, sho… Marsh Ray
- Re: [TLS] Rizzo claims implementation attach, sho… Nico Williams
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Eric Rescorla
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Yngve N. Pettersen
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Yngve N. Pettersen
- Re: [TLS] Rizzo claims implementation attach, sho… Martin Rex
- Re: [TLS] Rizzo claims implementation attach, sho… Yoav Nir