Subject: I-D Action: draft-roca-ipsecme-ptb-pts-attack-00.txt

From: [email-masked]
Date: Mon, 06 Jul 2015 07:47:14 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.

        Title           : Too Big or Too Small? The PTB-PTS ICMP-based Attack against IPsec Gateways
        Authors         : Vincent Roca
                          Saikou Fall
	Filename        : draft-roca-ipsecme-ptb-pts-attack-00.txt
	Pages           : 16
	Date            : 2015-07-06

Abstract:
   This document introduces the "Packet Too Big"-"Packet Too Small"
   Internet Control Message Protocol (ICMP) based attack against IPsec
   gateways.  We explain how an attacker having eavesdropping and packet
   injection capabilities, from the unsecure network where he only sees
   encrypted packets, can force a gateway to reduce the Path Maximum
   Transmission Unit (PMTU) of an IPsec tunnel to the minimum, which can
   trigger severe issues for the hosts behind this gateway: with a Linux
   host, depending on the PMTU discovery algorithm in use (i.e., PMTUd
   versus PLPMTUd) and protocol (TCP versus UDP), the attack either
   creates a Denial of Service or major performance penalties.  This
   attack highlights two fundamental problems, namely: (1) the
   impossibility to distinguish legitimate from illegitimate ICMP
   packets coming from the untrusted network, and (2) the contradictions
   in the way Path MTU is managed by some end hosts when this Path MTU
   is below the minimum packet size any link should support because of
   the IPsec encapsulation.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-roca-ipsecme-ptb-pts-attack/

There's also a htmlized version available at:
https://tools.ietf.org/html/draft-roca-ipsecme-ptb-pts-attack-00

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