[tcpm] I-D ACTION:draft-ietf-tcpm-tcp-antispoof-03.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the TCP Maintenance and Minor Extensions Working Group of the IETF.

	Title		: Defending TCP Against Spoofing Attacks
	Author(s)	: J. Touch
	Filename	: draft-ietf-tcpm-tcp-antispoof-03.txt
	Pages		: 27
	Date		: 2006-2-22

Recent analysis of potential attacks on core Internet infrastructure 
indicates an increased vulnerability of TCP connections to spurious 
resets (RSTs), sent with forged IP source addresses (spoofing).  TCP 
has always been susceptible to such RST spoofing attacks, which were 
indirectly protected by checking that the RST sequence number was 
inside the current receive window, as well as via the obfuscation of 
TCP endpoint and port numbers.  For pairs of well-known endpoints 
often over predictable port pairs, such as BGP or between web servers 
and well-known large-scale caches, increases in the path bandwidth-
delay product of a connection have sufficiently increased the receive 
window space that off-path third parties can guess a viable RST 
sequence number.  The susceptibility to attack increases as the 
square of the bandwidth, thus presents a significant vulnerability 
for recent high-speed networks.  This document addresses this 
vulnerability, discussing proposed solutions at the transport level 
and their inherent challenges, as well as existing network level 
solutions and the feasibility of their deployment.  This document 
focuses on vulnerabilities due to spoofed TCP segments, and includes 
a discussion of related ICMP spoofing attacks on TCP connections.

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