Protecting Internet Key Exchange Protocol Version 2 (IKEv2) Implementations from Distributed Denial-of-Service Attacks
RFC 8019

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01
• 02
• 03
• 04
• 05
• 06
• 07
• 08
• 09
• 10

Internet Engineering Task Force (IETF)                            Y. Nir
Request for Comments: 8019                                   Check Point
Category: Standards Track                                     V. Smyslov
ISSN: 2070-1721                                               ELVIS-PLUS
                                                           November 2016

      Protecting Internet Key Exchange Protocol Version 2 (IKEv2)
       Implementations from Distributed Denial-of-Service Attacks

Abstract

   This document recommends implementation and configuration best
   practices for Internet Key Exchange Protocol version 2 (IKEv2)
   Responders, to allow them to resist Denial-of-Service and Distributed
   Denial-of-Service attacks.  Additionally, the document introduces a
   new mechanism called "Client Puzzles" that helps accomplish this
   task.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   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/rfc8019.

Copyright Notice

   Copyright (c) 2016 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.

Nir & Smyslov                Standards Track                    [Page 1]
RFC 8019                DDoS Protection for IKEv2          November 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  The Vulnerability . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Defense Measures While the IKE SA Is Being Created  . . . . .   6
     4.1.  Retention Periods for Half-Open SAs . . . . . . . . . . .   6
     4.2.  Rate Limiting . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  The Stateless Cookie  . . . . . . . . . . . . . . . . . .   8
     4.4.  Puzzles . . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.5.  Session Resumption  . . . . . . . . . . . . . . . . . . .  11
     4.6.  Keeping Computed Shared Keys  . . . . . . . . . . . . . .  11
     4.7.  Preventing "Hash and URL" Certificate Encoding Attacks  .  11
     4.8.  IKE Fragmentation . . . . . . . . . . . . . . . . . . . .  12
   5.  Defense Measures after an IKE SA Is Created . . . . . . . . .  12
   6.  Plan for Defending a Responder  . . . . . . . . . . . . . . .  14
   7.  Using Puzzles in the Protocol . . . . . . . . . . . . . . . .  16
     7.1.  Puzzles in IKE_SA_INIT Exchange . . . . . . . . . . . . .  16
       7.1.1.  Presenting a Puzzle . . . . . . . . . . . . . . . . .  17
       7.1.2.  Solving a Puzzle and Returning the Solution . . . . .  19
       7.1.3.  Computing a Puzzle  . . . . . . . . . . . . . . . . .  20
       7.1.4.  Analyzing Repeated Request  . . . . . . . . . . . . .  21
       7.1.5.  Deciding Whether to Serve the Request . . . . . . . .  22
     7.2.  Puzzles in an IKE_AUTH Exchange . . . . . . . . . . . . .  23
       7.2.1.  Presenting the Puzzle . . . . . . . . . . . . . . . .  24
       7.2.2.  Solving the Puzzle and Returning the Solution . . . .  24
       7.2.3.  Computing the Puzzle  . . . . . . . . . . . . . . . .  25
       7.2.4.  Receiving the Puzzle Solution . . . . . . . . . . . .  25
   8.  Payload Formats . . . . . . . . . . . . . . . . . . . . . . .  26
     8.1.  PUZZLE Notification . . . . . . . . . . . . . . . . . . .  26
     8.2.  Puzzle Solution Payload . . . . . . . . . . . . . . . . .  27
   9.  Operational Considerations  . . . . . . . . . . . . . . . . .  28
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  28
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  30
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  30
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  30
     12.2.  Informative References . . . . . . . . . . . . . . . . .  31
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  31
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32