Re: [TLS] TLS 1.3 : small fragments attack

2017-12-30 Thread Yoav Nir
> On 30 Dec 2017, at 7:03, Peter Gutmann wrote: > > Jitendra Lulla writes: > >> The client can have a rogue TLS implementation with the following intentional >> changes: >> >> 0. Choose CBC with AES256-SHA56 or any other heavier (in terms of processing >> power requirements) and non parallel

Re: [TLS] TLS 1.3 : small fragments attack

2017-12-29 Thread Viktor Dukhovni
> On Dec 30, 2017, at 12:38 AM, Peter Gutmann wrote: > > I think your idea in general is a good one, standards should include sanity > limits on what you should and shouldn't accept (I've managed to cause crashes > and reboots and whatnot on different servers by sending valid but unexpected > d

Re: [TLS] TLS 1.3 : small fragments attack

2017-12-29 Thread Peter Gutmann
Jitendra Lulla writes: >But what if such records, from the same session, come in a quantity of 1 >or more per second which could be generated by uploading a 500 MB file by the >client? My comment was meant as a general observation on how hard anomaly-detection is. At what point do you decide

Re: [TLS] TLS 1.3 : small fragments attack

2017-12-29 Thread Jitendra Lulla
! On Sat, 12/30/17, Peter Gutmann wrote: Subject: Re: [TLS] TLS 1.3 : small fragments attack To: "tls@ietf.org" , "Jitendra Lulla" Date: Saturday, December 30, 2017, 5:03 AM Jitendra Lulla writes: >The client can have a rogue TLS implementa

Re: [TLS] TLS 1.3 : small fragments attack

2017-12-29 Thread Peter Gutmann
Jitendra Lulla writes: >The client can have a rogue TLS implementation with the following intentional >changes: > >0. Choose CBC with AES256-SHA56 or any other heavier (in terms of processing >power requirements) and non paralleliz'able cipher suite. > >1. After the handshake, always send all th