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Port randomization (draft-ietf-tsvwg-port-randomization)

Port randomization (draft-ietf-tsvwg-port-randomization). Michael Larsen & Fernando Gont. 73rd IETF Meeting, November 16-21, 2008 Minneapolis, MN, USA. Overview. This document describes how to defend transport protocols against blind attacks through ephemeral port obfuscation

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Port randomization (draft-ietf-tsvwg-port-randomization)

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  1. Port randomization(draft-ietf-tsvwg-port-randomization) Michael Larsen & Fernando Gont 73rd IETF Meeting, November 16-21, 2008 Minneapolis, MN, USA

  2. Overview • This document describes how to defend transport protocols against blind attacks through ephemeral port obfuscation • It provides an overview of the characteristics of a good ephemeral port selection algorithm • It describes a number of approaches for obfuscating ephemeral port numbers • It includes a survey of what popular implementations are doing with respect to ephemeral port selection

  3. Document history • This document was born in 2004 to address the problem of blind attacks against transport protocols. • It was adopted in 2007 as a wg item of the TSVWG. • It has been pretty stable during the last few revisions • We have received very thorough feedback from Mark Allman on the last revision (-02) • There has been some discussion on-list that will lead to a number of changes

  4. Changes to be incorporated in the next revision • The document title will be changed • “Port randomization” -> “Defending against blind attacks through ephemeral port obfuscation” • The comparision of the different algorithms will be backed-up by the results of ongoing work by Mark Allman. • Some text will be included pointing out that collisions might be avoided by maintaining the TIME-WAIT state also on the client-side. • RFC 1337 and [Faber et al, 1999] (“The TIME-WAIT state and its effect…”) will be referenced for a discussion of the TIME-WAIT issues. • A small comment will be included about the TCP SEQ numbers and the TCP timestamps heuristics performed by a number of implementations when processing incoming connection requests • A number of clarifications will be incorporated • Overall, all this feedback will require small changes to the document

  5. Moving the document forward • Our plan is to publish a revision (-03) of this document in the next few weeks that incorporates the aforementioned changes • We think that a WGLC should be started when that version is published

  6. Any comments or questions?

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