--- 1/draft-ietf-opsawg-sbom-access-03.txt 2022-01-05 06:13:11.810127203 -0800 +++ 2/draft-ietf-opsawg-sbom-access-04.txt 2022-01-05 06:13:11.854128297 -0800 @@ -1,20 +1,20 @@ Network Working Group E. Lear Internet-Draft Cisco Systems Intended status: Standards Track S. Rose -Expires: 27 April 2022 NIST - 24 October 2021 +Expires: 9 July 2022 NIST + 5 January 2022 Discovering and Retrieving Software Transparency and Vulnerability Information - draft-ietf-opsawg-sbom-access-03 + draft-ietf-opsawg-sbom-access-04 Abstract To improve cybersecurity posture, automation is necessary to locate what software is running on a device, whether that software has known vulnerabilities, and what, if any recommendations suppliers may have. This memo specifies a model to provide access to this information. It may optionally be discovered through manufacturer usage descriptions. @@ -26,74 +26,79 @@ 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 27 April 2022. + This Internet-Draft will expire on 9 July 2022. Copyright Notice - Copyright (c) 2021 IETF Trust and the persons identified as the + Copyright (c) 2022 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. + extracted from this document must include Revised BSD License text as + described in Section 4.e of the Trust Legal Provisions and are + provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1.1. Cases Not Addressed . . . . . . . . . . . . . . . . . . . 4 + 1.1. Cases Not Addressed . . . . . . . . . . . . . . . . . . . 5 1.2. How This Information Is Retrieved . . . . . . . . . . . . 5 1.3. Formats . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1.4. Discussion points . . . . . . . . . . . . . . . . . . . . 5 - 2. The .well-known/transparency endpoint set . . . . . . . . . . 6 + 1.4. Discussion points . . . . . . . . . . . . . . . . . . . . 6 + 2. The well-known transparency endpoint set . . . . . . . . . . 6 3. The mud-transparency extension model extension . . . . . . . 6 4. The mud-sbom augmentation to the MUD YANG model . . . . . . . 7 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Without ACLS . . . . . . . . . . . . . . . . . . . . . . 10 5.2. SBOM Located on the Device . . . . . . . . . . . . . . . 12 5.3. Further contact required. . . . . . . . . . . . . . . . . 13 5.4. With ACLS . . . . . . . . . . . . . . . . . . . . . . . . 14 6. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 7.1. MUD Extension . . . . . . . . . . . . . . . . . . . . . . 17 - 7.2. Well-Known Prefix . . . . . . . . . . . . . . . . . . . . 17 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 17 - 8.2. Informative References . . . . . . . . . . . . . . . . . 18 - Appendix A. Changes from Earlier Versions . . . . . . . . . . . 18 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 + 7.2. YANG Registration . . . . . . . . . . . . . . . . . . . . 17 + 7.3. Well-Known Prefix . . . . . . . . . . . . . . . . . . . . 17 + 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 + 9.1. Normative References . . . . . . . . . . . . . . . . . . 18 + 9.2. Informative References . . . . . . . . . . . . . . . . . 18 + Appendix A. Changes from Earlier Versions . . . . . . . . . . . 19 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 1. Introduction A number of activities have been working to improve visibility to what software is running on a system, and what vulnerabilities that - software may have. + software may have[EO2021]. Put simply, we seek to answer two classes of questions *at scale*: * Is this system vulnerable to a particular vulnerability? * Which devices in a particular environment contain vulnerabilities that require some action? + This memo doesn't specify the format of this information, but rather + only how to locate and retrieve these objects. + Software bills of materials (SBOMs) are descriptions of what software, including versioning and dependencies, a device contains. There are different SBOM formats such as Software Package Data Exchange [SPDX] or CycloneDX[CycloneDX12]. System vulnerabilities may similarly be described using several data formats, including the aforementioned CycloneDX, Common Vulnerability Reporting Framework [CVRF], the Common Security Advisory Format [CSAF]. This information is typically used to report to customers the state of a system. @@ -109,23 +114,25 @@ specified in this memo. One can provide only an SBOM, only vulnerability information, or both an SBOM and vulnerability information. Note that SBOM formats may also carry other information, the most common being any licensing terms. Because this specification is neutral regarding content, it is left for format developers such as the Linux Foundation, OASIS, and ISO to decide what attributes they will support. - This specification does not allow for vulnerability information to be + This memo does not specify how vulnerability information may be retrieved directly from the endpoint. That's because vulnerability information changes occur at different rates to software updates. + However, some SBOM formats may also contain vulnerability + information. SBOMs and vulnerability information are advertised and retrieved through the use of a YANG augmentation of the Manufacturer User Description (MUD) model [RFC8520]. Note that the schema creates a grouping that can also be used independently of MUD. Moreover, other MUD features, such as access controls, needn't be present. The mechanisms specified in this document are meant to satisfy several use cases: @@ -148,21 +155,21 @@ * through some form of out-of-band contact with the supplier. In the first case, devices will have interfaces that permit direct retrieval. Examples of these interfaces might be an HTTP, COAP or [OpenC2] endpoint for retrieval. There may also be private interfaces as well. In the second case, when a device does not have an appropriate retrieval interface, but one is directly available from the - manufacturer, a URI to that information must be discovered. + manufacturer, a URI to that information MUST be discovered. In the third case, a supplier may wish to make an SBOM or vulnerability information available under certain circumstances, and may need to individually evaluate requests. The result of that evaluation might be the SBOM or vulnerability itself or a restricted URL or no access. To enable application-layer discovery, this memo defines a well-known URI [RFC8615]. Management or orchestration tools can query this well-known URI to retrieve a system's SBOM or vulnerability @@ -223,29 +230,30 @@ information is available from the same location, both sbom and vuln nodes MUST indicate that. Network management systems retrieving this information MUST take note that the identical resource is being retrieved rather than retrieving it twice. 1.4. Discussion points The following is discussion to be removed at time of RFC publication. * Is the model structured correctly? + * Are there other retrieval mechanisms that need to be specified? * Do we need to be more specific in how to authenticate and retrieve SBOMs? * What are the implications if the MUD URL is an extension in a certificate (e.g. an IDevID cert)? -2. The .well-known/transparency endpoint set +2. The well-known transparency endpoint set Two well known endpoints are defined: * "/.well-known/sbom" retrieves an SBOM. * "/.well-known/openc2" is the HTTPS binding to OpenC2. As discussed previously, the precise format of a response is based on the Content-type provided. @@ -280,42 +288,42 @@ +--:(vuln-contact-info) +--rw contact-uri inet:uri 4. The mud-sbom augmentation to the MUD YANG model file "ietf-mud-transparency@2021-10-22.yang" module ietf-mud-transparency { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-mud-transparency"; - prefix mud-transparency; + prefix mudtx; import ietf-inet-types { prefix inet; reference "RFC 6991"; } import ietf-mud { prefix mud; reference "RFC 8520"; } organization "IETF OPSAWG (Ops Area) Working Group"; contact "WG Web: http://tools.ietf.org/wg/opsawg/ WG List: opsawg@ietf.org Editor: Eliot Lear lear@cisco.com Editor: Scott Rose scott.rose@nist.gov"; description "This YANG module augments the ietf-mud model to provide for - reporting of SBOMs. + reporting of SBOMs and vulnerability information. Copyright (c) 2020 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). @@ -327,21 +335,22 @@ 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here. "; revision 2021-07-06 { description "Initial proposed standard."; reference - "RFC XXXX: Extension for software transparency"; + "RFC XXXX: Discovering and Retrieving Software Transparency + and Vulnerability Information"; } grouping transparency-extension { description "Transparency extension grouping"; container transparency { description "container of methods to get an SBOM."; choice sbom-retrieval-method { description @@ -446,99 +455,96 @@ 5.1. Without ACLS This first MUD file demonstrates how to get SBOM and vulnerability information without ACLs. { "ietf-mud:mud": { "mud-version": 1, "extensions": [ + "ol", "transparency" ], - "ietf-mud-transparency:transparency": { - "sboms": [ - { - "version-info": "ExOS1.1", - "sbom-url": "https://iot.example.com/info/modelX/sbom.json" - } + "ol": { + "owners": [ + "Copyright (c) Example, Inc. 2022. All Rights Reserved" ], + "spdx-tag": "0BSD" + }, + "mudtx:transparency": { + "sbom-local-well-known": "https", "vuln-url": "https://iot.example.com/info/modelX/csaf.json" }, "mud-url": "https://iot.example.com/modelX.json", "mud-signature": "https://iot.example.com/modelX.p7s", - "last-update": "2021-07-09T05:57:58+00:00", + "last-update": "2022-01-05T13:29:12+00:00", "cache-validity": 48, "is-supported": true, "systeminfo": "retrieving vuln and SBOM info via a cloud service", "mfg-name": "Example, Inc.", "documentation": "https://iot.example.com/doc/modelX", "model-name": "modelX" } } The second example demonstrates that just SBOM information is included. { "ietf-mud:mud": { "mud-version": 1, "extensions": [ + "ol", "transparency" ], - "ietf-mud-transparency:transparency": { - "sboms": [ - { - "version-info": "ExOS1.1", - "sbom-url": "https://iot.example.com/info/modelX/sbom.json" - } - ] + "ol": { + "owners": [ + "Copyright (c) Example, Inc. 2022. All Rights Reserved" + ], + "spdx-tag": "0BSD" + }, + "mudtx:transparency": { + "sbom-local-well-known": "https" }, "mud-url": "https://iot.example.com/modelX.json", "mud-signature": "https://iot.example.com/modelX.p7s", - "last-update": "2021-07-09T06:03:21+00:00", + "last-update": "2022-01-05T13:29:47+00:00", "cache-validity": 48, "is-supported": true, "systeminfo": "retrieving vuln and SBOM info via a cloud service", "mfg-name": "Example, Inc.", "documentation": "https://iot.example.com/doc/modelX", "model-name": "modelX" } } 5.2. SBOM Located on the Device In this example, the SBOM is retrieved from the device, while vulnerability information is available from the cloud. This is likely a common case, because vendors may learn of vulnerability information more frequently than they update software. { "ietf-mud:mud": { "mud-version": 1, "extensions": [ - "ol", "transparency" ], - "ol": { - "owners": [ - "Copyright (c) Example, Inc. 2021. All Rights Reserved" - ], - "spdx-tag": "0BSD" - }, - "ietf-mud-transparency:transparency": { + "mudtx:transparency": { "sbom-local-well-known": "https", "vuln-url": "https://iot-device.example.com/info/modelX/csaf.json" }, "mud-url": "https://iot-device.example.com/modelX.json", "mud-signature": "https://iot-device.example.com/modelX.p7s", - "last-update": "2021-07-09T06:06:13+00:00", + "last-update": "2022-01-05T13:25:14+00:00", "cache-validity": 48, "is-supported": true, "systeminfo": "retrieving vuln and SBOM info via a cloud service", "mfg-name": "Example, Inc.", "documentation": "https://iot-device.example.com/doc/modelX", "model-name": "modelX" } } 5.3. Further contact required. @@ -571,90 +577,92 @@ 5.4. With ACLS Finally, here is a complete example where the device provides SBOM and vulnerability information, as well as access-control information. { "ietf-mud:mud": { "mud-version": 1, "extensions": [ + "ol", "transparency" ], - "ietf-mud-transparency:transparency": { - "sboms": [ - { - "version-info": "ExOS1.1", - "sbom-url": "https://iot.example.com/info/modelX/sbom.json" - } + "ol": { + "owners": [ + "Copyright (c) Example, Inc. 2022. All Rights Reserved" ], + "spdx-tag": "0BSD" + }, + "mudtx:transparency": { + "sbom-local-well-known": "https", "vuln-url": "https://iot.example.com/info/modelX/csaf.json" }, "mud-url": "https://iot.example.com/modelX.json", "mud-signature": "https://iot.example.com/modelX.p7s", - "last-update": "2021-07-09T06:19:39+00:00", + "last-update": "2022-01-05T13:30:31+00:00", "cache-validity": 48, "is-supported": true, "systeminfo": "retrieving vuln and SBOM info via a cloud service", "mfg-name": "Example, Inc.", "documentation": "https://iot.example.com/doc/modelX", "model-name": "modelX", "from-device-policy": { "access-lists": { "access-list": [ { - "name": "mud-15060-v4fr" + "name": "mud-65443-v4fr" } ] } }, "to-device-policy": { "access-lists": { "access-list": [ { - "name": "mud-15060-v4to" + "name": "mud-65443-v4to" } ] } } }, "ietf-access-control-list:acls": { "acl": [ { - "name": "mud-15060-v4to", + "name": "mud-65443-v4to", "type": "ipv4-acl-type", "aces": { "ace": [ { "name": "cl0-todev", "matches": { "ipv4": { - "ietf-acldns:src-dnsname": "cloud.example.com" + "ietf-acldns:src-dnsname": "iotserver.example.com" } }, "actions": { "forwarding": "accept" } } ] } }, { - "name": "mud-15060-v4fr", + "name": "mud-65443-v4fr", "type": "ipv4-acl-type", "aces": { "ace": [ { "name": "cl0-frdev", "matches": { "ipv4": { - "ietf-acldns:dst-dnsname": "cloud.example.com" + "ietf-acldns:dst-dnsname": "iotserver.example.com" } }, "actions": { "forwarding": "accept" } } ] } } ] @@ -662,37 +670,37 @@ } At this point, the management system can attempt to retrieve the SBOM, and determine which format is in use through the content-type header on the response to a GET request, independently repeat the process for vulnerability information, and apply ACLs, as appropriate. 6. Security Considerations - SBOMs provide an inventory of software. If firmware is available to + SBOMs provide an inventory of software. If software is available to an attacker, the attacker may well already be able to derive this very same software inventory. Manufacturers MAY restrict access to SBOM information using appropriate authorization semantics within HTTP. In particular, if a system attempts to retrieve an SBOM via HTTP and the client is not authorized, the server MUST produce an appropriate error, with instructions on how to register a particular client. One example may be to issue a certificate to the client for this purpose after a registration process has taken place. Another example would involve the use of OAUTH in combination with a federations of SBOM servers. Another risk is a skew in the SBOM listing and the actual software inventory of a device/container. For example, a manufacturer may update the SBOM on its server, but an individual device has not been upgraded yet. This may result in an incorrect policy being applied - to a device. A unique mapping of a device's firmware version and its + to a device. A unique mapping of a device's software version and its SBOM can minimize this risk. To further mitigate attacks against a device, manufacturers SHOULD recommend access controls through the normal MUD mechanism. Vulnerability information is generally made available to such databases as NIST's National Vulnerability Database. It is possible that vendor may wish to release information early to some customers. We do not discuss here whether that is a good idea, but if it is employed, then appropriate access controls and authorization would be @@ -701,38 +709,54 @@ 7. IANA Considerations 7.1. MUD Extension The IANA is requested to add "transparency" to the MUD extensions registry as follows: Extension Name: transparency Standard reference: This document -7.2. Well-Known Prefix +7.2. YANG Registration + + The following YANG module should be registered in the "YANG Module + Names" registry: + + Name: ietf-mud + URN: urn:ietf:params:xml:ns:yang:ietf-mud-transparency + Prefix: mudtx + Registrant contact: The IESG + Reference: This memo + +7.3. Well-Known Prefix The following well known URIs are requested in accordance with [RFC8615]: URI suffix: "sbom" Change controller: "IETF" Specification document: This memo Related information: See ISO/IEC 19970-2 and SPDX.org URI suffix: "openc2" Change controller: "IETF" Specification document: This memo Related information: OpenC2 Project -8. References +8. Acknowledgments -8.1. Normative References + Thanks to Russ Housley, Dick Brooks, Tom Petch, Nicolas Comstedt, who + provided revew comments. + +9. References + +9.1. 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, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . @@ -742,41 +766,46 @@ [RFC8520] Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage Description Specification", RFC 8520, DOI 10.17487/RFC8520, March 2019, . [RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers (URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019, . -8.2. Informative References +9.2. Informative References [CSAF] OASIS, "Common Security Advisory Format", July 2021, . [CVRF] Santos, O., Ed., "Common Vulnerability Reporting Framework - (CVRF) Version 1.2", September 2017, . [CycloneDX12] cylonedx.org, "CycloneDX XML Reference v1.2", May 2020. + [EO2021] Biden, J., "Executive Order 14028, Improving the Nations + Cybersecurity", May 2021. + [OpenC2] Lemire, D., Ed., "Specification for Transfer of OpenC2 Messages via HTTPS Version 1.0", July 2019, . [SPDX] The Linux Foundation, "SPDX Specification 2.1", 2016. Appendix A. Changes from Earlier Versions + Draft -04: * Address review comments + Draft -02: * include vulnerability information Draft -01: * some modest changes Draft -00: