draft-ietf-bfd-secure-sequence-numbers-01.txt   draft-ietf-bfd-secure-sequence-numbers-02.txt 
Network Working Group M. Jethanandani Network Working Group M. Jethanandani
Internet-Draft S. Agarwal Internet-Draft S. Agarwal
Intended status: Standards Track Cisco Systems, Inc Intended status: Standards Track Cisco Systems, Inc
Expires: May 25, 2018 A. Mishra Expires: November 26, 2018 A. Mishra
O3b Networks O3b Networks
A. Saxena A. Saxena
Ciena Corporation Ciena Corporation
A. Dekok A. Dekok
Network RADIUS SARL Network RADIUS SARL
November 21, 2017 May 25, 2018
Secure BFD Sequence Numbers Secure BFD Sequence Numbers
draft-ietf-bfd-secure-sequence-numbers-01 draft-ietf-bfd-secure-sequence-numbers-02
Abstract Abstract
This document describes a security enhancements for the BFD packet's This document describes a security enhancements for the BFD packet's
sequence number. sequence number.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." 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 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. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Theory of operations . . . . . . . . . . . . . . . . . . . . 2 2. Theory of operations . . . . . . . . . . . . . . . . . . . . 2
3. Impact of using a hash . . . . . . . . . . . . . . . . . . . 4 3. Impact of using a hash . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
BFD [RFC5880] section 6.7 describes the use of monotonically BFD [RFC5880] section 6.7 describes the use of monotonically
incrementing 32-bit sequence numbers for use in authentication of BFD incrementing 32-bit sequence numbers for use in authentication of BFD
packets. While this method protects against simple replay attacks, packets. While this method protects against simple replay attacks,
the monotonically incrementing sequence numbers are predictable and the monotonically incrementing sequence numbers are predictable and
vulnerable to more complex attack vectors. This document proposes vulnerable to more complex attack vectors. This document proposes
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4. IANA Considerations 4. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an Note to RFC Editor: this section may be removed on publication as an
RFC. RFC.
5. Security Considerations 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 6. Acknowledgements
7. References 7. References
7.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>. <https://www.rfc-editor.org/info/rfc5880>.
7.2. Informative References 7.2. Informative References
[I-D.ietf-bfd-optimizing-authentication] [I-D.ietf-bfd-optimizing-authentication]
Jethanandani, M., Mishra, A., Saxena, A., and M. Bhatia, Jethanandani, M., Mishra, A., Saxena, A., and M. Bhatia,
"Optimizing BFD Authentication", draft-ietf-bfd- "Optimizing BFD Authentication", draft-ietf-bfd-
optimizing-authentication-03 (work in progress), June optimizing-authentication-04 (work in progress), November
2017. 2017.
Authors' Addresses Authors' Addresses
Mahesh Jethanandani Mahesh Jethanandani
Cisco Systems, Inc Cisco Systems, Inc
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95070 San Jose, CA 95070
USA USA
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Email: mishra.ashesh@gmail.com Email: mishra.ashesh@gmail.com
Ankur Saxena Ankur Saxena
Ciena Corporation Ciena Corporation
3939 North First Street 3939 North First Street
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: ankurpsaxena@gmail.com Email: ankurpsaxena@gmail.com
Alan DeKok Alan DeKok
Network RADIUS SARL Network RADIUS SARL
100 Centrepointe Drive #200 100 Centrepointe Drive #200
Ottowa, ON K2G 6B1 Ottowa, ON K2G 6B1
Canada Canada
Email: aland@networkradious.com Email: aland@freeradius.org
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