--- 1/draft-ietf-lamps-ocsp-nonce-03.txt 2020-09-02 19:13:10.090344866 -0700 +++ 2/draft-ietf-lamps-ocsp-nonce-04.txt 2020-09-02 19:13:10.106345273 -0700 @@ -1,44 +1,44 @@ LAMPS M. Sahni, Ed. Internet-Draft Palo Alto Networks -Updates: 6960 (if approved) August 14, 2020 +Updates: 6960 (if approved) September 2, 2020 Intended status: Standards Track -Expires: February 15, 2021 +Expires: March 6, 2021 OCSP Nonce Extension - draft-ietf-lamps-ocsp-nonce-03 + draft-ietf-lamps-ocsp-nonce-04 Abstract This document specifies the updated format of the Nonce extension in Online Certificate Status Protocol (OCSP) request and response 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 - avoid replay attacks. This document updates the RFC 6960 + avoid replay attacks. This document updates the RFC 6960. 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 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 February 15, 2021. + This Internet-Draft will expire on March 6, 2021. Copyright Notice Copyright (c) 2020 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 @@ -51,33 +51,33 @@ Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 2. OCSP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Nonce Extension . . . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 4 3.1. Replay Attack . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Nonce Collision . . . . . . . . . . . . . . . . . . . . . 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 5.2. Changes to Appendix B.2 OCSP in ASN.1 - 2008 Syntax . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction This document updates the usage and format of the Nonce extension 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. Due to not having an upper or lower limit of the length of the Nonce extension, the OCSP responders that follow [RFC6960] may be vulnerable to various attacks like Denial of Service attacks [RFC4732], chosen prefix attacks to get a desired signature from the OCSP responder and possible evasions that can use the Nonce extension 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 document updates the [RFC6960]. @@ -85,23 +85,23 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. OCSP Extensions The message format for the OCSP request and response is defined in - the [RFC6960]. It also defines the standard extensions for OCSP - messages based on the extension model employed in X.509 version 3 - certificates (see [RFC5280]). The following is a list of standard + the [RFC6960]. [RFC6960] also defines the standard extensions for + OCSP messages based on the extension model employed in X.509 version + 3 certificates (see [RFC5280]). The following is a list of standard extensions that can be used in the OCSP messages by the OCSP responder and OCSP client. * Nonce * CRL References * Acceptable Response Types * Archive Cutoff * CRL Entry Extensions * Service Locator * Preferred Signature Algorithms @@ -119,31 +119,32 @@ The nonce cryptographically binds a request and a response to prevent replay attacks. The nonce is included as one of the requestExtensions in requests, while in responses it would be included as one of the responseExtensions. In both the request and the response, the nonce will be identified by the object identifier 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 least 1 octet and can be up to 32 octets. A server MUST reject any OCSP request having a Nonce extension with - length of more than 32 octets with the malformedRequest - OCSPResponseStatus as described in section 4.2.1 of [RFC6960] + length of 0 octets or more than 32 octets with the malformedRequest + OCSPResponseStatus as described in section 4.2.1 of [RFC6960]. The value of the nonce MUST be generated using a cryptographically - strong pseudorandom number generator. The OCSP clients SHOULD use a - length of 32 octets for the Nonce extension. The minimum nonce - length of 1 octet is defined to provide the backward compatibility - with older clients following [RFC6960] however, the newer OCSP - clients MUST use a length of at least 16 octets for Nonce extension. - The OCSP responder MAY choose to ignore Nonce extension for the - requests where length of the Nonce extension is less than 16 octets. + strong pseudorandom number generator (see [RFC4086]). The OCSP + clients SHOULD use a length of 32 octets for the Nonce extension. + The minimum nonce length of 1 octet is defined to provide the + backward compatibility with older clients following [RFC6960] + however, the newer OCSP clients MUST use a length of at least 16 + octets for Nonce extension. The OCSP responder MAY choose to ignore + 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-nonce OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 } Nonce ::= OCTET STRING(SIZE(1..32)) 3. Security Considerations The security considerations of OCSP, in general, are described in the [RFC6960]. The Nonce extension is used to avoid replay attacks @@ -230,20 +231,25 @@ . [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams, "X.509 Internet Public Key Infrastructure Online Certificate Status Protocol - OCSP", RFC 6960, DOI 10.17487/RFC6960, June 2013, . 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, + . + [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet Denial-of-Service Considerations", RFC 4732, DOI 10.17487/RFC4732, December 2006, . [RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online Certificate Status Protocol (OCSP) Profile for High-Volume Environments", RFC 5019, DOI 10.17487/RFC5019, September 2007, .