Secure BFD Sequence Numbers
draft-sonal-bfd-secure-sequence-numbers-00

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Last updated 2017-02-22
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Network Working Group                                    M. Jethanandani
Internet-Draft                                                S. Agarwal
Intended status: Standards Track                      Cisco Systems, Inc
Expires: August 26, 2017                                       A. Mishra
                                                               A. Saxena
                                                       Ciena Corporation
                                                                A. Dekok
                                                     Network RADIUS SARL
                                                       February 22, 2017

                      Secure BFD Sequence Numbers
               draft-sonal-bfd-secure-sequence-numbers-00

Abstract

   This document describes a security enhancements for the BFD packet's
   sequence number.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 26, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Jethanandani, et al.     Expires August 26, 2017                [Page 1]
Internet-Draft        Securing next sequence number        February 2017

   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
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Theory of operations  . . . . . . . . . . . . . . . . . . . .   2
   3.  Impact of using a hash  . . . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   BFD [RFC5880] section 6.7 describes the use of monotonically
   incrementing 32-bit sequence numbers for use in authentication of BFD
   packets.  While this method protects against simple replay attacks,
   the monotonically incrementing sequence numbers are predictable and
   vulnerable to more complex attack vectors.  This document proposes
   the use of non-monotonically-incrementing sequence numbers in BFD
   authentication TLVs to enhance the security of BFD sessions.
   Specifically, the document presents a method to generate pseudo-
   random sequence numbers on the frame by algorithmically hashing
   monotonically increasing sequence numbers.  Further security may be
   introduced by resetting un-encrypted sequence to a random value when
   the 32-bit sequence number rolls-over.

2.  Theory of operations

   Instead of monotonically increasing the sequence number or even
   occasionally monotonically increasing the sequence number, the next
   sequence number is generated by computing a hash on what would have
   been the next sequence number using a shared key.  That computed hash
   is then inserted into the sequence number field of the packet.  In
   case of BFD Authentication [I-D.ietf-bfd-optimizing-authentication],
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