Heuristics for Detecting ESP-NULL Packets
RFC 5879
Document | Type | RFC - Informational (May 2010; No errata) | |
---|---|---|---|
Authors | Daniel McDonald , Tero Kivinen | ||
Last updated | 2015-10-14 | ||
Replaces | draft-kivinen-ipsecme-esp-null-heuristics | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5879 (Informational) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Pasi Eronen | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) T. Kivinen Request for Comments: 5879 AuthenTec, Inc. Category: Informational D. McDonald ISSN: 2070-1721 Oracle Corporation May 2010 Heuristics for Detecting ESP-NULL Packets Abstract This document describes a set of heuristics for distinguishing IPsec ESP-NULL (Encapsulating Security Payload without encryption) packets from encrypted ESP packets. These heuristics can be used on intermediate devices, like traffic analyzers, and deep-inspection engines, to quickly decide whether or not a given packet flow is encrypted, i.e., whether or not it can be inspected. Use of these heuristics does not require any changes made on existing IPsec hosts that are compliant with RFC 4303. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc5879. Kivinen & McDonald Informational [Page 1] RFC 5879 Heuristics for Detecting ESP-NULL May 2010 Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction ....................................................3 1.1. Applicability: Heuristic Traffic Inspection and Wrapped ESP ................................................4 1.2. Terminology ................................................4 2. Other Options ...................................................5 2.1. AH .........................................................5 2.2. Mandating by Policy ........................................6 2.3. Modifying ESP ..............................................6 3. Description of Heuristics .......................................6 4. IPsec Flows .....................................................7 5. Deep-Inspection Engine ..........................................9 6. Special and Error Cases .........................................9 7. UDP Encapsulation ..............................................10 8. Heuristic Checks ...............................................10 8.1. ESP-NULL Format ...........................................11 8.2. Self Describing Padding Check .............................12 8.3. Protocol Checks ...........................................14 8.3.1. TCP Checks .........................................15 8.3.2. UDP Checks .........................................16 8.3.3. ICMP Checks ........................................16 8.3.4. SCTP Checks ........................................17 8.3.5. IPv4 and IPv6 Tunnel Checks ........................17 9. Security Considerations ........................................17 10. References ....................................................18 10.1. Normative References .....................................18 10.2. Informative References ...................................18 Appendix A. Example Pseudocode ...................................20 A.1. Fastpath ..................................................20 A.2. Slowpath ..................................................23 Kivinen & McDonald Informational [Page 2] RFC 5879 Heuristics for Detecting ESP-NULL May 2010 1. Introduction The ESP (Encapsulating Security Payload [RFC4303]) protocol can be used with NULL encryption [RFC2410] to provide authentication, integrity protection, and optionally replay detection, but withoutShow full document text