draft-ietf-lamps-ocsp-nonce-03.txt   draft-ietf-lamps-ocsp-nonce-04.txt 
LAMPS M. Sahni, Ed. LAMPS M. Sahni, Ed.
Internet-Draft Palo Alto Networks Internet-Draft Palo Alto Networks
Updates: 6960 (if approved) August 14, 2020 Updates: 6960 (if approved) September 2, 2020
Intended status: Standards Track Intended status: Standards Track
Expires: February 15, 2021 Expires: March 6, 2021
OCSP Nonce Extension OCSP Nonce Extension
draft-ietf-lamps-ocsp-nonce-03 draft-ietf-lamps-ocsp-nonce-04
Abstract Abstract
This document specifies the updated format of the Nonce extension in This document specifies the updated format of the Nonce extension in
Online Certificate Status Protocol (OCSP) request and response Online Certificate Status Protocol (OCSP) request and response
messages. OCSP is used to check the status of a certificate and the messages. OCSP is used to check the status of a certificate and the
Nonce extension is used in the OCSP request and response messages to Nonce extension is used in the OCSP request and response messages to
avoid replay attacks. This document updates the RFC 6960 avoid replay attacks. This document updates the RFC 6960.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 February 15, 2021. This Internet-Draft will expire on March 6, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 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
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. OCSP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3 2. OCSP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Nonce Extension . . . . . . . . . . . . . . . . . . . . . 3 2.1. Nonce Extension . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 4 3. Security Considerations . . . . . . . . . . . . . . . . . . . 4
3.1. Replay Attack . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Replay Attack . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Nonce Collision . . . . . . . . . . . . . . . . . . . . . 4 3.2. Nonce Collision . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Changes to Appendix B. of RFC 6960 . . . . . . . . . . . . . 4 5. Changes to Appendix B. of RFC 6960 . . . . . . . . . . . . . 5
5.1. Changes to Appendix B.1. OCSP in ASN.1 - 1998 Syntax . . 5 5.1. Changes to Appendix B.1. OCSP in ASN.1 - 1998 Syntax . . 5
5.2. Changes to Appendix B.2 OCSP in ASN.1 - 2008 Syntax . . . 5 5.2. Changes to Appendix B.2 OCSP in ASN.1 - 2008 Syntax . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6 6.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
This document updates the usage and format of the Nonce extension This document updates the usage and format of the Nonce extension
used in OCSP request and response messages. This extension was used in OCSP request and response messages. This extension was
previously defined in section 4.1.1 of [RFC6960]. The [RFC6960] does previously defined in section 4.4.1 of [RFC6960]. The [RFC6960] does
not mention any minimum and maximum length of the nonce extension. not mention any minimum and maximum length of the nonce extension.
Due to not having an upper or lower limit of the length of the Nonce Due to not having an upper or lower limit of the length of the Nonce
extension, the OCSP responders that follow [RFC6960] may be extension, the OCSP responders that follow [RFC6960] may be
vulnerable to various attacks like Denial of Service attacks vulnerable to various attacks like Denial of Service attacks
[RFC4732], chosen prefix attacks to get a desired signature from the [RFC4732], chosen prefix attacks to get a desired signature from the
OCSP responder and possible evasions that can use the Nonce extension OCSP responder and possible evasions that can use the Nonce extension
data for evasion. This document specifies a lower limit of 1 and an data for evasion. This document specifies a lower limit of 1 and an
upper limit of 32 to the length of the Nonce extension. This upper limit of 32 to the length of the Nonce extension. This
document updates the [RFC6960]. document updates the [RFC6960].
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. OCSP Extensions 2. OCSP Extensions
The message format for the OCSP request and response is defined in The message format for the OCSP request and response is defined in
the [RFC6960]. It also defines the standard extensions for OCSP the [RFC6960]. [RFC6960] also defines the standard extensions for
messages based on the extension model employed in X.509 version 3 OCSP messages based on the extension model employed in X.509 version
certificates (see [RFC5280]). The following is a list of standard 3 certificates (see [RFC5280]). The following is a list of standard
extensions that can be used in the OCSP messages by the OCSP extensions that can be used in the OCSP messages by the OCSP
responder and OCSP client. responder and OCSP client.
* Nonce * Nonce
* CRL References * CRL References
* Acceptable Response Types * Acceptable Response Types
* Archive Cutoff * Archive Cutoff
* CRL Entry Extensions * CRL Entry Extensions
* Service Locator * Service Locator
* Preferred Signature Algorithms * Preferred Signature Algorithms
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The nonce cryptographically binds a request and a response to prevent The nonce cryptographically binds a request and a response to prevent
replay attacks. The nonce is included as one of the replay attacks. The nonce is included as one of the
requestExtensions in requests, while in responses it would be requestExtensions in requests, while in responses it would be
included as one of the responseExtensions. In both the request and included as one of the responseExtensions. In both the request and
the response, the nonce will be identified by the object identifier the response, the nonce will be identified by the object identifier
id-pkix-ocsp-nonce, while the extnValue is the value of the nonce. id-pkix-ocsp-nonce, while the extnValue is the value of the nonce.
If Nonce extension is present then the length of nonce MUST be at If Nonce extension is present then the length of nonce MUST be at
least 1 octet and can be up to 32 octets. least 1 octet and can be up to 32 octets.
A server MUST reject any OCSP request having a Nonce extension with A server MUST reject any OCSP request having a Nonce extension with
length of more than 32 octets with the malformedRequest length of 0 octets or more than 32 octets with the malformedRequest
OCSPResponseStatus as described in section 4.2.1 of [RFC6960] OCSPResponseStatus as described in section 4.2.1 of [RFC6960].
The value of the nonce MUST be generated using a cryptographically The value of the nonce MUST be generated using a cryptographically
strong pseudorandom number generator. The OCSP clients SHOULD use a strong pseudorandom number generator (see [RFC4086]). The OCSP
length of 32 octets for the Nonce extension. The minimum nonce clients SHOULD use a length of 32 octets for the Nonce extension.
length of 1 octet is defined to provide the backward compatibility The minimum nonce length of 1 octet is defined to provide the
with older clients following [RFC6960] however, the newer OCSP backward compatibility with older clients following [RFC6960]
clients MUST use a length of at least 16 octets for Nonce extension. however, the newer OCSP clients MUST use a length of at least 16
The OCSP responder MAY choose to ignore Nonce extension for the octets for Nonce extension. The OCSP responder MAY choose to ignore
requests where length of the Nonce extension is less than 16 octets. Nonce extension for the requests where length of the Nonce extension
is less than 16 octets.
id-pkix-ocsp OBJECT IDENTIFIER ::= { id-ad-ocsp } id-pkix-ocsp OBJECT IDENTIFIER ::= { id-ad-ocsp }
id-pkix-ocsp-nonce OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 } id-pkix-ocsp-nonce OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 }
Nonce ::= OCTET STRING(SIZE(1..32)) Nonce ::= OCTET STRING(SIZE(1..32))
3. Security Considerations 3. Security Considerations
The security considerations of OCSP, in general, are described in the The security considerations of OCSP, in general, are described in the
[RFC6960]. The Nonce extension is used to avoid replay attacks [RFC6960]. The Nonce extension is used to avoid replay attacks
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predicted nonce and can replay them, thus defeating the purpose of predicted nonce and can replay them, thus defeating the purpose of
using nonce. Therefore the value of Nonce extension in the OCSP using nonce. Therefore the value of Nonce extension in the OCSP
request MUST contain cryptographically strong randomness and MUST be request MUST contain cryptographically strong randomness and MUST be
freshly generated at the time of creating the OCSP request. Also if freshly generated at the time of creating the OCSP request. Also if
the length of the nonce extension is too small e.g. 1 octet then an the length of the nonce extension is too small e.g. 1 octet then an
on-path attacker can prefetch responses with all the possible values on-path attacker can prefetch responses with all the possible values
of the nonce and replay a matching nonce. of the nonce and replay a matching nonce.
4. IANA Considerations 4. IANA Considerations
This document does not call for any IANA actions. This document does not call for any IANA actions.
5. Changes to Appendix B. of RFC 6960 5. Changes to Appendix B. of RFC 6960
This section updates the ASN.1 definitions of the OCSP Nonce This section updates the ASN.1 definitions of the OCSP Nonce
extension in the Appendix B.1 and Appendix B.2 of the [RFC6960] The extension in the Appendix B.1 and Appendix B.2 of the [RFC6960] The
Appendix B.1 defines OCSP using ASN.1 - 1998 Syntax and Appendix B.2 Appendix B.1 defines OCSP using ASN.1 - 1998 Syntax and Appendix B.2
defines OCSP using ASN.1 - 2008 Syntax defines OCSP using ASN.1 - 2008 Syntax
5.1. Changes to Appendix B.1. OCSP in ASN.1 - 1998 Syntax 5.1. Changes to Appendix B.1. OCSP in ASN.1 - 1998 Syntax
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<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
Galperin, S., and C. Adams, "X.509 Internet Public Key Galperin, S., and C. Adams, "X.509 Internet Public Key
Infrastructure Online Certificate Status Protocol - OCSP", Infrastructure Online Certificate Status Protocol - OCSP",
RFC 6960, DOI 10.17487/RFC6960, June 2013, RFC 6960, DOI 10.17487/RFC6960, June 2013,
<https://www.rfc-editor.org/info/rfc6960>. <https://www.rfc-editor.org/info/rfc6960>.
6.2. Informative References 6.2. Informative References
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<https://www.rfc-editor.org/info/rfc4086>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732, Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006, DOI 10.17487/RFC4732, December 2006,
<https://www.rfc-editor.org/info/rfc4732>. <https://www.rfc-editor.org/info/rfc4732>.
[RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online [RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online
Certificate Status Protocol (OCSP) Profile for High-Volume Certificate Status Protocol (OCSP) Profile for High-Volume
Environments", RFC 5019, DOI 10.17487/RFC5019, September Environments", RFC 5019, DOI 10.17487/RFC5019, September
2007, <https://www.rfc-editor.org/info/rfc5019>. 2007, <https://www.rfc-editor.org/info/rfc5019>.
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