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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 6480 == Outdated reference: A later version (-07) exists of draft-ietf-sidrops-rpki-rsc-06 Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group R. Bush 3 Internet-Draft Arrcus & Internet Initiative Japan 4 Intended status: Standards Track R. Housley 5 Expires: 4 September 2022 Vigil Security 6 3 March 2022 8 The I in RPKI does not stand for Identity 9 draft-ietf-sidrops-rpki-has-no-identity-04 11 Abstract 13 There is a false notion that Internet Number Resources (INRs) in the 14 RPKI can be associated with the real-world identity of the 'owner' of 15 an INR. This document attempts to put that notion to rest. 17 Requirements Language 19 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 20 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 21 "OPTIONAL" in this document are to be interpreted as described in BCP 22 14 [RFC2119] [RFC8174] when, and only when, they appear in all 23 capitals, as shown here. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on 4 September 2022. 42 Copyright Notice 44 Copyright (c) 2022 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 49 license-info) in effect on the date of publication of this document. 50 Please review these documents carefully, as they describe your rights 51 and restrictions with respect to this document. Code Components 52 extracted from this document must include Revised BSD License text as 53 described in Section 4.e of the Trust Legal Provisions and are 54 provided without warranty as described in the Revised BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. The Bottom Line . . . . . . . . . . . . . . . . . . . . . . . 3 60 3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 62 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 63 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 64 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 65 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 66 7.2. Informative References . . . . . . . . . . . . . . . . . 6 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 69 1. Introduction 71 The Resource Public Key Infrastructure (RPKI), see [RFC6480], 72 "Represents the allocation hierarchy of IP address space and 73 Autonomous System (AS) numbers," which are collectively known as 74 Internet Number Resources (INRs). Since initial deployment, the RPKI 75 has grown to include other similar resource and routing data, e.g. 76 Router Keying for BGPsec, [RFC8635]. 78 In security terms, the phrase "Public Key" implies there is also a 79 corresponding private key [RFC5280]. The RPKI's strong authority 80 over ownership of INRs has misled some people toward a desire to use 81 RPKI private keys to sign arbitrary documents attesting that the INR 82 'owner' of those resources has attested to the authenticity of the 83 document content. But in reality, the RPKI certificate is only an 84 authorization to speak for the explicitly identified INRs; it is 85 explicitly not intended for authentication of the 'owners' of the 86 INRs. This situation is emphasized in Section 2.1 of [RFC6480]. 88 It has been suggested that one could authenticate real-world business 89 transactions with the signatures of INR holders. E.g. Bill's Bait 90 and Sushi could use their AS in the RPKI to sign a Letter of 91 Authorization (LOA) for some other party to rack and stack hardware 92 owned by BB&S. Unfortunately, this is not formally feasible. 94 The I in RPKI actually stands for "Infrastructure," as in Resource 95 Public Key Infrastructure, not for "Identity". In fact, the RPKI 96 does not provide any association between INRs and the real world 97 holder(s) of those INRs. The RPKI provides authorization to speak 98 for the named IP address blocks and AS numbers. 100 In short, avoid the desire to use RPKI certificates for any purpose 101 other than the verification of authorizations associated with the 102 delegation of INRs or attestations related to INRs. Instead, 103 recognize that these authorizations and attestations take place 104 irrespective of the identity of a RPKI private key holder. 106 2. The Bottom Line 108 The RPKI was designed and specified to sign certificates for use 109 within the RPKI itself and to generate Route Origin Authorizations 110 (ROAs), [RFC6480], for use in routing. Its design intentionally 111 precluded use for attesting to real-world identity as, among other 112 issues, it would expose the Certification Authority (CA) to 113 liability. 115 That the RPKI does not authenticate real-world identity is a feature, 116 not a bug. If it tried to do so, aside from the liability, it would 117 end in a world of complexity with no proof of termination, as X.400 118 learned. 120 Registries such as the Regional Internet Registries (RIRs) provide 121 INR to real-world identity mapping through whois and similar 122 services. They claim to be authoritative, at least for the INRs 123 which they allocate. 125 RPKI-based credentials of INRs MUST NOT be used to authenticate real- 126 world documents or transactions without some formal external 127 authentication of the INR and the authority for the actually 128 anonymous INR holder to authenticate the particular document or 129 transaction. 131 Given sufficient external, i.e. non-RPKI, verification of authority, 132 the use of RPKI-based credentials seems superfluous. 134 3. Discussion 136 The RPKI base document, [RFC6480], Section 2.1 says explicitly "An 137 important property of this PKI is that certificates do not attest to 138 the identity of the subject." 139 The Template for a Certification Practice Statement (CPS) for the 140 Resource PKI (RPKI) [RFC7382] Section 3.1, Naming, makes very clear 141 that "The Subject name in each certificate SHOULD NOT be meaningful;" 142 and goes on to do so at some length. 144 Normally, the INR holder does not hold the private key attesting to 145 their resources; the Certification Authority (CA) does. The INR 146 holder has a real-world business relationship with the CA for which 147 they have likely signed real-world documents. 149 As the INR owner does not have the keying material, they rely on the 150 CA, to which they presumably present credentials, to manipulate their 151 INRs. These credentials may be userid/password (with two factor 152 authentication one hopes), a hardware token, client browser 153 certificates, etc. 155 Hence schemes such as [I-D.ietf-sidrops-rpki-rta] and 156 [I-D.ietf-sidrops-rpki-rsc] must go to great lengths to extract the 157 supposedly relevant keys from the CA. 159 For some particular INR, say Bill's Bait and Sushi's Autonomous 160 System (AS) number, someone out on the net probably has the 161 credentials to the CA account in which BB&S's INRs are registered. 162 That could be the owner of BB&S, Roberto's Taco Stand, an IT vendor, 163 or the Government of Elbonia. One simply can not know. 165 In large organizations, INR management is often compartmentalized 166 with no authority over anything beyond dealing with INR registration. 167 The INR manager for Bill's Bait and Sushi is unlikely to be 168 authorized to conduct bank transactions for BB&S, or even to 169 authorize access to BB&S's servers in some colocation facility. 171 Then there is the temporal issue. The owner of that AS may be BB&S 172 today when some document was signed, and could be the Government of 173 Elbonia tomorrow. Or the resource could have been administratively 174 moved from one CA to another, likely requiring a change of keys. If 175 so, how does one determine if the signature on the real-world 176 document is still valid? 178 While Ghostbuster Records [RFC6493] may seem to identify real-world 179 entities, their semantic content is completely arbitrary, and does 180 not attest to INR ownership. They are merely clues for operational 181 support contact in case of technical RPKI problems. 183 Usually, before registering INRs, CAs require proof of INR ownership 184 via external documentation and authorities. It is somewhat droll 185 that the CPS Template, [RFC7382], does not mention any diligence the 186 CA must, or even might, conduct to assure the INRs are in fact owned 187 by a registrant. 189 That someone can provide 'proof of possession' of the private key 190 signing over a particular INR should not be taken to imply that they 191 are a valid legal representative of the organization in possession of 192 that INR. They could be just an INR administrative person. 194 Autonomous System Numbers do not identify real-world entities. They 195 are identifiers some network operators 'own' and are only used for 196 loop detection in routing. They have no inherent semantics other 197 than uniqueness. 199 4. Security Considerations 201 Attempts to use RPKI data to authenticate real-world documents or 202 other artifacts requiring identity are invalid and misleading. 204 When a document is signed with the private key associated with an 205 RPKI certificate, the signer is speaking for the INRs, the IP address 206 space and Autonomous System (AS) numbers, in the certificate. This 207 is not an identity; this is an authorization. In schemes such as 208 [I-D.ietf-sidrops-rpki-rta] and [I-D.ietf-sidrops-rpki-rsc] the 209 signed message further narrows this scope of INRs. The INRs in the 210 message are a subset of the INRs in the certificate. If the 211 signature is valid, the message content comes from a party that is 212 authorized to speak for that subset of INRs. 214 Control of INRs for an entity could be used to falsely authorize 215 transactions or documents for which the INR manager has no authority. 217 RPKI-based credentials of INRs MUST NOT be used to authenticate real- 218 world documents or transactions without some formal external 219 authentication of the INR and the authority for the actually 220 anonymous INR holder to authenticate the particular document or 221 transaction. 223 5. IANA Considerations 225 This document has no IANA Considerations. 227 6. Acknowledgments 229 The authors thank George Michaelson and Job Snijders for lively 230 discussion, Geoff Huston for some more formal text, Ties de Kock for 231 useful suggestions, and last but not least, Biff for the loan of 232 Bill's Bait and Sushi. 234 7. References 236 7.1. Normative References 238 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 239 Requirement Levels", BCP 14, RFC 2119, 240 DOI 10.17487/RFC2119, March 1997, 241 . 243 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 244 Housley, R., and W. Polk, "Internet X.509 Public Key 245 Infrastructure Certificate and Certificate Revocation List 246 (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, 247 . 249 [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support 250 Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, 251 February 2012, . 253 [RFC7382] Kent, S., Kong, D., and K. Seo, "Template for a 254 Certification Practice Statement (CPS) for the Resource 255 PKI (RPKI)", BCP 173, RFC 7382, DOI 10.17487/RFC7382, 256 April 2015, . 258 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 259 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 260 May 2017, . 262 [RFC8635] Bush, R., Turner, S., and K. Patel, "Router Keying for 263 BGPsec", RFC 8635, DOI 10.17487/RFC8635, August 2019, 264 . 266 7.2. Informative References 268 [I-D.ietf-sidrops-rpki-rsc] 269 Snijders, J., Harrison, T., and B. Maddison, "Resource 270 Public Key Infrastructure (RPKI) object profile for Signed 271 Checklist (RSC)", Work in Progress, Internet-Draft, draft- 272 ietf-sidrops-rpki-rsc-06, 12 February 2022, 273 . 276 [I-D.ietf-sidrops-rpki-rta] 277 Michaelson, G. G., Huston, G., Harrison, T., Bruijnzeels, 278 T., and M. Hoffmann, "A profile for Resource Tagged 279 Attestations (RTAs)", Work in Progress, Internet-Draft, 280 draft-ietf-sidrops-rpki-rta-00, 21 January 2021, 281 . 284 [RFC6493] Bush, R., "The Resource Public Key Infrastructure (RPKI) 285 Ghostbusters Record", RFC 6493, DOI 10.17487/RFC6493, 286 February 2012, . 288 Authors' Addresses 290 Randy Bush 291 Arrcus & Internet Initiative Japan 292 5147 Crystal Springs 293 Bainbridge Island, WA 98110 294 United States of America 295 Email: randy@psg.com 297 Russ Housley 298 Vigil Security, LLC 299 516 Dranesville Road 300 Herndon, VA, 20170 301 United States of America 302 Email: housley@vigilsec.com