A new Request for Comments is now available in online RFC libraries. RFC 5961 Title: Improving TCP's Robustness to Blind In-Window Attacks Author: A. Ramaiah, R. Stewart, M. Dalal Status: Standards Track Stream: IETF Date: August 2010 Mailbox: ananth@cisco.com, rstewart@huawei.com, mdalal@cisco.com Pages: 19 Characters: 44717 Updates/Obsoletes/SeeAlso: None I-D Tag: draft-ietf-tcpm-tcpsecure-13.txt URL: http://www.rfc-editor.org/rfc/rfc5961.txt TCP has historically been considered to be protected against spoofed off-path packet injection attacks by relying on the fact that it is difficult to guess the 4-tuple (the source and destination IP addresses and the source and destination ports) in combination with the 32-bit sequence number(s). A combination of increasing window sizes and applications using longer-term connections (e.g., H-323 or Border Gateway Protocol (BGP) [RFC4271]) have left modern TCP implementations more vulnerable to these types of spoofed packet injection attacks. Many of these long-term TCP applications tend to have predictable IP addresses and ports that makes it far easier for the 4-tuple (4-tuple is the same as the socket pair mentioned in RFC 793) to be guessed. Having guessed the 4-tuple correctly, an attacker can inject a TCP segment with the RST bit set, the SYN bit set or data into a TCP connection by systematically guessing the sequence number of the spoofed segment to be in the current receive window. This can cause the connection to abort or cause data corruption. This document specifies small modifications to the way TCP handles inbound segments that can reduce the chances of a successful attack. [STANDARDS TRACK] This document is a product of the TCP Maintenance and Minor Extensions Working Group of the IETF. This is now a Proposed Standard Protocol. STANDARDS TRACK: This document specifies an Internet standards track protocol for the Internet community,and requests discussion and suggestions for improvements. Please refer to the current edition of the Internet Official Protocol Standards (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. This announcement is sent to the IETF-Announce and rfc-dist lists. To subscribe or unsubscribe, see http://www.ietf.org/mailman/listinfo/ietf-announce http://mailman.rfc-editor.org/mailman/listinfo/rfc-dist For searching the RFC series, see http://www.rfc-editor.org/rfcsearch.html. For downloading RFCs, see http://www.rfc-editor.org/rfc.html. Requests for special distribution should be addressed to either the author of the RFC in question, or to rfc-editor@rfc-editor.org. Unless specifically noted otherwise on the RFC itself, all RFCs are for unlimited distribution. The RFC Editor Team Association Management Solutions, LLC _______________________________________________ IETF-Announce mailing list IETF-Announce@ietf.org https://www.ietf.org/mailman/listinfo/ietf-announce