--- 1/draft-ietf-bfd-secure-sequence-numbers-01.txt 2018-05-25 15:13:08.338984187 -0700 +++ 2/draft-ietf-bfd-secure-sequence-numbers-02.txt 2018-05-25 15:13:08.354984572 -0700 @@ -1,24 +1,24 @@ Network Working Group M. Jethanandani Internet-Draft S. Agarwal Intended status: Standards Track Cisco Systems, Inc -Expires: May 25, 2018 A. Mishra +Expires: November 26, 2018 A. Mishra O3b Networks A. Saxena Ciena Corporation A. Dekok Network RADIUS SARL - November 21, 2017 + May 25, 2018 Secure BFD Sequence Numbers - draft-ietf-bfd-secure-sequence-numbers-01 + draft-ietf-bfd-secure-sequence-numbers-02 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 @@ -32,47 +32,47 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on May 25, 2018. + This Internet-Draft will expire on November 26, 2018. Copyright Notice - Copyright (c) 2017 IETF Trust and the persons identified as the + Copyright (c) 2018 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 (https://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 . . . . . . . . . . . . . . . . . . . . . . . . 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 + 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 + 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 5 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 @@ -169,41 +169,63 @@ 4. IANA Considerations This document makes no request of IANA. Note to RFC Editor: this section may be removed on publication as an RFC. 5. Security Considerations + While the proposed mechanism improves overall security of BFD + mechanism, the security consderations are listed below: + + Because of the fast rate of BFD sesions and it is difficult to change + the keys (used for hashing the sequence number) during the operation + of a BFD session without affecting the stabiluty of the BFD session. + It is, therefore, recommended to admistratively disable the BFD + session before changing the keys. If the keys are not changed, an + attacker can use a replay attack. + + Using this method allows the BFD end-points to detect a malicious + packet (the decrypted sequence number will not be in sequence) the + behavior of the session when such a packet is detected is based on + the implementation. A flood of such malicious packets may cause a + session to report BFD session to be operationally down. + + The hashing algorithm and key size will determine the difficulty for + an attacker to decipher the key from the transmitted BFD frames. + Sequential nature of the payload (sequence numbers) simplifies the + decoding of the key. It is, therefore, recommended to use longer + keys or more secure hashing algorithms. + 6. Acknowledgements 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, . 7.2. Informative References [I-D.ietf-bfd-optimizing-authentication] Jethanandani, M., Mishra, A., Saxena, A., and M. Bhatia, "Optimizing BFD Authentication", draft-ietf-bfd- - optimizing-authentication-03 (work in progress), June + optimizing-authentication-04 (work in progress), November 2017. Authors' Addresses Mahesh Jethanandani Cisco Systems, Inc 170 West Tasman Drive San Jose, CA 95070 USA @@ -223,17 +244,18 @@ Email: mishra.ashesh@gmail.com Ankur Saxena Ciena Corporation 3939 North First Street San Jose, CA 95134 USA Email: ankurpsaxena@gmail.com + Alan DeKok Network RADIUS SARL 100 Centrepointe Drive #200 Ottowa, ON K2G 6B1 Canada - Email: aland@networkradious.com + Email: aland@freeradius.org