Re: [TLS] Rizzo claims implementation attach, should be interesting
Martin Rex <mrex@sap.com> Thu, 29 September 2011 14:40 UTC
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From: Martin Rex <mrex@sap.com>
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To: yngve@opera.com
Date: Thu, 29 Sep 2011 16:42:46 +0200
In-Reply-To: <op.v2kqrrnkkvaitl@lessa-ii.oslo.os> from "Yngve N. Pettersen" at Sep 29, 11 04:34:29 pm
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Cc: asteingruebl@paypal-inc.com, tls@ietf.org
Subject: Re: [TLS] Rizzo claims implementation attach, should be interesting
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Thank you for the detailed and very helpful information! I also believe that fragmenting application data is likely to break brittle application design that silently assumes application data boundaries (network read&writes, respectively SSL_read()&SSL_write()) will be preserved. So _not_ upsetting the peers TLS stack might not be a sufficient precondition to make a mitigation work. :-( -Martin Yngve N. Pettersen wrote: > > The test only used a split record for application data, and was only > performed if the server supported on of the CBC ciphersuites supported by > the prober, and a successful HTTP request for / without split record had > been sent earlier in the test. > > Determining failure required detecting two successive failures that either > did not return a response at all, or a 400+ error code that was not the > same as was received in the baseline request. (200/300 was considered a > success regardless ) > > Five different split policies were tested (0, 1, 2, blocksize-1, blocksize > -2 bytes), each with or without having the blocks in the same TCP record. > The above number was with the two records in the same TCP record (as that > had a significantly lower failure rate). > > The above numbers is the combined failure rate for servers that support > AES, or only support 3DES. (AES is presumed to be selected by these > servers). > > I have previously seen HTTPS servers mishandle two HTTP requests in the > same record (the second was ignored); my guess is that this is the same > thing: An assumption that a single SSL/TLS Application record contain just > a single, complete HTTPS request. My guess is that the responsible servers > are front-ends, firewalls or similar, not servers like Apache with modSSL > or IIS. > > At least one server return "ET is not a recognized HTTP method", > apparently having dropped the record with the "G" part of the request. > > BTW: 0.045% failed all 5 of the tests, so I consider it likely that there > is no split policy that will work for all servers.
- 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