rfc9319.original   rfc9319.txt 
Internet Engineering Task Force (IETF) Y. Gilad Internet Engineering Task Force (IETF) Y. Gilad
Internet-Draft Hebrew University of Jerusalem Request for Comments: 9319 Hebrew University of Jerusalem
Intended status: Best Current Practice S. Goldberg BCP: 185 S. Goldberg
Expires: 15 February 2023 Boston University Category: Best Current Practice Boston University
K. Sriram ISSN: 2070-1721 K. Sriram
USA NIST USA NIST
J. Snijders J. Snijders
Fastly Fastly
B. Maddison B. Maddison
Workonline Communications Workonline Communications
14 August 2022 October 2022
The Use of maxLength in the RPKI The Use of maxLength in the Resource Public Key Infrastructure (RPKI)
draft-ietf-sidrops-rpkimaxlen-15
Abstract Abstract
This document recommends ways to reduce the forged-origin hijack This document recommends ways to reduce the forged-origin hijack
attack surface by prudently limiting the set of IP prefixes that are attack surface by prudently limiting the set of IP prefixes that are
included in a Route Origin Authorization (ROA). One recommendation included in a Route Origin Authorization (ROA). One recommendation
is to avoid using the maxLength attribute in ROAs except in some is to avoid using the maxLength attribute in ROAs except in some
specific cases. The recommendations complement and extend those in specific cases. The recommendations complement and extend those in
RFC 7115. The document also discusses the creation of ROAs for RFC 7115. This document also discusses the creation of ROAs for
facilitating the use of Distributed Denial of Service (DDoS) facilitating the use of Distributed Denial of Service (DDoS)
mitigation services. Considerations related to ROAs and origin mitigation services. Considerations related to ROAs and RPKI-based
validation in the context of destination-based Remotely Triggered Route Origin Validation (RPKI-ROV) in the context of destination-
Discard Route (RTDR) (elsewhere referred to as "Remotely Triggered based Remotely Triggered Discard Route (RTDR) (elsewhere referred to
Black Hole") filtering are also highlighted. as "Remotely Triggered Black Hole") filtering are also highlighted.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This memo documents an Internet Best Current Practice.
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 This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
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BCPs is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 15 February 2023. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9319.
Copyright Notice Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Requirements
1.2. Documentation Prefixes . . . . . . . . . . . . . . . . . 4 1.2. Documentation Prefixes
2. Suggested Reading . . . . . . . . . . . . . . . . . . . . . . 4 2. Suggested Reading
3. Forged-Origin Sub-prefix Hijack . . . . . . . . . . . . . . . 4 3. Forged-Origin Sub-Prefix Hijack
4. Measurements of the RPKI . . . . . . . . . . . . . . . . . . 7 4. Measurements of the RPKI
5. Recommendations about Minimal ROAs and maxLength . . . . . . 7 5. Recommendations about Minimal ROAs and maxLength
5.1. Facilitating Ad Hoc Routing Changes and DDoS 5.1. Facilitating Ad Hoc Routing Changes and DDoS Mitigation
Mitigation . . . . . . . . . . . . . . . . . . . . . . . 8 5.2. Defensive De-aggregation in Response to Prefix Hijacks
5.2. Defensive De-aggregation In Response To Prefix Hijacks . 10 6. Considerations for RTDR Filtering Scenarios
6. Considerations for RTDR Filtering Scenarios . . . . . . . . . 11 7. User Interface Design Recommendations
7. User Interface Design Recommendations . . . . . . . . . . . . 11 8. Operational Considerations
8. Operational Considerations . . . . . . . . . . . . . . . . . 12 9. Security Considerations
9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 10. IANA Considerations
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 11. References
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 11.1. Normative References
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 11.2. Informative References
12.1. Normative References . . . . . . . . . . . . . . . . . . 13 Acknowledgments
12.2. Informative References . . . . . . . . . . . . . . . . . 14 Authors' Addresses
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
The RPKI [RFC6480] uses Route Origin Authorizations (ROAs) to create The Resource Public Key Infrastructure (RPKI) [RFC6480] uses Route
a cryptographically verifiable mapping from an IP prefix to a set of Origin Authorizations (ROAs) to create a cryptographically verifiable
autonomous systems (ASes) that are authorized to originate that mapping from an IP prefix to a set of Autonomous Systems (ASes) that
prefix. Each ROA contains a set of IP prefixes, and the AS number of are authorized to originate that prefix. Each ROA contains a set of
one of the ASes authorized to originate all the IP prefixes in the IP prefixes and the AS number of one of the ASes authorized to
set [RFC6482]. The ROA is cryptographically signed by the party that originate all the IP prefixes in the set [RFC6482]. The ROA is
holds a certificate for the set of IP prefixes. cryptographically signed by the party that holds a certificate for
the set of IP prefixes.
The ROA format also supports a maxLength attribute. According to The ROA format also supports a maxLength attribute. According to
[RFC6482], "When present, the maxLength specifies the maximum length [RFC6482], "When present, the maxLength specifies the maximum length
of the IP address prefix that the AS is authorized to advertise." of the IP address prefix that the AS is authorized to advertise."
Thus, rather than requiring the ROA to list each prefix that the AS Thus, rather than requiring the ROA to list each prefix that the AS
is authorized to originate, the maxLength attribute provides a is authorized to originate, the maxLength attribute provides a
shorthand that authorizes an AS to originate a set of IP prefixes. shorthand that authorizes an AS to originate a set of IP prefixes.
However, measurements of RPKI deployments have found that the use of However, measurements of RPKI deployments have found that the use of
the maxLength in ROAs tends to lead to security problems. In the maxLength attribute in ROAs tends to lead to security problems.
particular, measurements taken in June 2017 showed that of the In particular, measurements taken in June 2017 showed that of the
prefixes specified in ROAs that use the maxLength attribute, 84% were prefixes specified in ROAs that use the maxLength attribute, 84% were
vulnerable to a forged-origin sub-prefix hijack [HARMFUL]. The vulnerable to a forged-origin sub-prefix hijack [GSG17]. The forged-
forged-origin prefix or sub-prefix hijack involves inserting the origin prefix or sub-prefix hijack involves inserting the legitimate
legitimate AS as specified in the ROA as the origin AS in the AS as specified in the ROA as the origin AS in the AS_PATH; the
AS_PATH, and can be launched against any IP prefix/sub-prefix that hijack can be launched against any IP prefix/sub-prefix that has a
has a ROA. Consider a prefix/sub-prefix that has a ROA but is ROA. Consider a prefix/sub-prefix that has a ROA that is unused
unused, i.e., not announced in BGP by a legitimate AS. A forged (i.e., not announced in BGP by a legitimate AS). A forged-origin
origin hijack involving such a prefix/sub-prefix can propagate widely hijack involving such a prefix/sub-prefix can propagate widely
throughout the Internet. On the other hand, if the prefix/sub-prefix throughout the Internet. On the other hand, if the prefix/sub-prefix
were announced by the legitimate AS, then the propagation of the were announced by the legitimate AS, then the propagation of the
forged-origin hijack is somewhat limited because of its increased forged-origin hijack is somewhat limited because of its increased
AS_PATH length relative to the legitimate announcement. Of course, AS_PATH length relative to the legitimate announcement. Of course,
forged-origin hijacks are harmful in both cases but the extent of forged-origin hijacks are harmful in both cases, but the extent of
harm is greater for unannounced prefixes. See Section 3 for detailed harm is greater for unannounced prefixes. See Section 3 for detailed
discussion. discussion.
For this reason, this document recommends that, whenever possible, For this reason, this document recommends that, whenever possible,
operators SHOULD use "minimal ROAs" that authorize only those IP operators SHOULD use "minimal ROAs" that authorize only those IP
prefixes that are actually originated in BGP, and no other prefixes. prefixes that are actually originated in BGP, and no other prefixes.
Further, it recommends ways to reduce the forged-origin attack Further, it recommends ways to reduce the forged-origin attack
surface by prudently limiting the address space that is included in surface by prudently limiting the address space that is included in
Route Origin Authorizations (ROAs). One recommendation is to avoid ROAs. One recommendation is to avoid using the maxLength attribute
using the maxLength attribute in ROAs except in some specific cases. in ROAs except in some specific cases. The recommendations
The recommendations complement and extend those in [RFC7115]. The complement and extend those in [RFC7115]. The document also
document also discusses the creation of ROAs for facilitating the use discusses the creation of ROAs for facilitating the use of DDoS
of Distributed Denial of Service (DDoS) mitigation services. mitigation services. Considerations related to ROAs and RPKI-ROV in
Considerations related to ROAs and origin validation in the context the context of destination-based Remotely Triggered Discard Route
of destination-based Remotely Triggered Discard Route (RTDR) (RTDR) (elsewhere referred to as "Remotely Triggered Black Hole")
(elsewhere referred to as "Remotely Triggered Black Hole") filtering filtering are also highlighted.
are also highlighted.
One ideal place to implement the ROA related recommendations is in Please note that the term "RPKI-based Route Origin Validation" and
the corresponding acronym "RPKI-ROV" that are used in this document
mean the same as the term "Prefix Origin Validation" used in
[RFC6811].
One ideal place to implement the ROA-related recommendations is in
the user interfaces for configuring ROAs. Recommendations for the user interfaces for configuring ROAs. Recommendations for
implementors of such user interfaces are provided in Section 7 implementors of such user interfaces are provided in Section 7.
Best current practices described in this document require no changes
to the RPKI specification and will not increase the number of signed The practices described in this document require no changes to the
ROAs in the RPKI because ROAs already support lists of IP prefixes RPKI specifications and will not increase the number of signed ROAs
in the RPKI because ROAs already support lists of IP prefixes
[RFC6482]. [RFC6482].
1.1. Requirements 1.1. Requirements
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
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
1.2. Documentation Prefixes 1.2. Documentation Prefixes
The documentation prefixes recommended in [RFC5737] are insufficient The documentation prefixes recommended in [RFC5737] are insufficient
for use as example prefixes in this document. Therefore, this for use as example prefixes in this document. Therefore, this
document uses [RFC1918] address space for constructing example document uses the address space defined in [RFC1918] for constructing
prefixes. example prefixes.
Note that although the examples in this document are presented using Note that although the examples in this document are presented using
IPv4 prefixes, all the analysis thereof and the recommendations made IPv4 prefixes, all the analysis thereof and the recommendations made
are equally valid for the equivalent IPv6 cases. are equally valid for the equivalent IPv6 cases.
2. Suggested Reading 2. Suggested Reading
It is assumed that the reader understands BGP [RFC4271], RPKI It is assumed that the reader understands BGP [RFC4271], RPKI
[RFC6480], Route Origin Authorizations (ROAs) [RFC6482], RPKI-based [RFC6480], ROAs [RFC6482], RPKI-ROV [RFC6811], and BGPsec [RFC8205].
Prefix Validation [RFC6811], and BGPsec [RFC8205].
3. Forged-Origin Sub-prefix Hijack 3. Forged-Origin Sub-Prefix Hijack
A detailed description and discussion of forged-origin sub-prefix A detailed description and discussion of forged-origin sub-prefix
hijacks are presented here, especially considering the case when the hijacks are presented here, especially considering the case when the
sub-prefix is not announced in BGP. The forged-origin sub-prefix sub-prefix is not announced in BGP. The forged-origin sub-prefix
hijack is relevant to a scenario in which: hijack is relevant to a scenario in which:
(1) the RPKI [RFC6480] is deployed, and (1) the RPKI [RFC6480] is deployed, and
(2) routers use RPKI origin validation to drop invalid routes (2) routers use RPKI-ROV to drop invalid routes [RFC6811], but
[RFC6811], but
(3) BGPsec [RFC8205] (or any similar method to validate the (3) BGPsec [RFC8205] (or any similar method to validate the
truthfulness of the BGP AS_PATH attribute) is not deployed. truthfulness of the BGP AS_PATH attribute) is not deployed.
Note that this set of assumptions accurately describes a substantial Note that this set of assumptions accurately describes a substantial
and growing number of large Internet networks at the time of writing. and growing number of large Internet networks at the time of writing.
The forged-origin sub-prefix hijack [RFC7115] [GCHSS] is described The forged-origin sub-prefix hijack [RFC7115] [GCHSS] is described
here using a running example. here using a running example.
Consider the IP prefix 192.168.0.0/16 which is allocated to an Consider the IP prefix 192.168.0.0/16, which is allocated to an
organization that also operates AS 64496. In BGP, AS 64496 organization that also operates AS 64496. In BGP, AS 64496
originates the IP prefix 192.168.0.0/16 as well as its sub-prefix originates the IP prefix 192.168.0.0/16 as well as its sub-prefix
192.168.225.0/24. Therefore, the RPKI should contain a ROA 192.168.225.0/24. Therefore, the RPKI should contain a ROA
authorizing AS 64496 to originate these two IP prefixes. authorizing AS 64496 to originate these two IP prefixes.
Suppose, however, the organization issues and publishes a ROA Suppose, however, the organization issues and publishes a ROA
including a maxLength value of 24: including a maxLength value of 24:
ROA:(192.168.0.0/16-24, AS 64496) ROA:(192.168.0.0/16-24, AS 64496)
We refer to the above as a "loose ROA" since it authorizes AS 64496 We refer to the above as a "loose ROA" since it authorizes AS 64496
to originate any sub-prefix of 192.168.0.0/16 up to and including to originate any sub-prefix of 192.168.0.0/16 up to and including
length /24, rather than only those prefixes that are intended to be length /24, rather than only those prefixes that are intended to be
announced in BGP. announced in BGP.
Because AS 64496 only originates two prefixes in BGP: 192.168.0.0/16 Because AS 64496 only originates two prefixes in BGP (192.168.0.0/16
and 192.168.225.0/24, all other prefixes authorized by the "loose and 192.168.225.0/24), all other prefixes authorized by the loose ROA
ROA" (for instance, 192.168.0.0/24), are vulnerable to the following (for instance, 192.168.0.0/24) are vulnerable to the following
forged-origin sub-prefix hijack [RFC7115] [GCHSS]: forged-origin sub-prefix hijack [RFC7115] [GCHSS]:
The hijacker AS 64511 sends a BGP announcement "192.168.0.0/24: AS The hijacker AS 64511 sends a BGP announcement "192.168.0.0/24: AS
64511, AS 64496", falsely claiming that AS 64511 is a neighbor of 64511, AS 64496", falsely claiming that AS 64511 is a neighbor of
AS 64496 and falsely claiming that AS 64496 originates the IP AS 64496 and that AS 64496 originates the IP prefix
prefix 192.168.0.0/24. In fact, the IP prefix 192.168.0.0/24 is 192.168.0.0/24. In fact, the IP prefix 192.168.0.0/24 is not
not originated by AS 64496. originated by AS 64496.
The hijacker's BGP announcement is valid according to the RPKI The hijacker's BGP announcement is valid according to the RPKI
since the ROA (192.168.0.0/16-24, AS 64496) authorizes AS 64496 to since the ROA (192.168.0.0/16-24, AS 64496) authorizes AS 64496 to
originate BGP routes for 192.168.0.0/24. originate BGP routes for 192.168.0.0/24.
Because AS 64496 does not actually originate a route for Because AS 64496 does not actually originate a route for
192.168.0.0/24, the hijacker's route is the only route for 192.168.0.0/24, the hijacker's route is the only route for
192.168.0.0/24. Longest-prefix-match routing ensures that the 192.168.0.0/24. Longest-prefix-match routing ensures that the
hijacker's route to the sub-prefix 192.168.0.0/24 is always hijacker's route to the sub-prefix 192.168.0.0/24 is always
preferred over the legitimate route to 192.168.0.0/16 originated preferred over the legitimate route to 192.168.0.0/16 originated
by AS 64496. by AS 64496.
Thus, the hijacker's route propagates through the Internet, and Thus, the hijacker's route propagates through the Internet, and
traffic destined for IP addresses in 192.168.0.0/24 will be delivered traffic destined for IP addresses in 192.168.0.0/24 will be delivered
to the hijacker. to the hijacker.
The forged-origin sub-prefix hijack would have failed if a "minimal The forged-origin sub-prefix hijack would have failed if a minimal
ROA" described below was used instead of the "loose ROA". In this ROA as described in Section 5 was used instead of the loose ROA. In
example, a "minimal ROA" would be: this example, a minimal ROA would be:
ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496) ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496)
This ROA is "minimal" because it includes only those IP prefixes that This ROA is "minimal" because it includes only those IP prefixes that
AS 64496 originates in BGP, but no other IP prefixes [RFC6907]. AS 64496 originates in BGP, but no other IP prefixes [RFC6907].
The "minimal ROA" renders AS 64511's BGP announcement invalid The minimal ROA renders AS 64511's BGP announcement invalid because:
because:
(1) this ROA "covers" the attacker's announcement (since (1) this ROA "covers" the attacker's announcement (since
192.168.0.0/24 is a sub-prefix of 192.168.0.0/16), and 192.168.0.0/24 is a sub-prefix of 192.168.0.0/16), and
(2) there is no ROA "matching" the attacker's announcement (there (2) there is no ROA "matching" the attacker's announcement (there is
is no ROA for AS 64511 and IP prefix 192.168.0.0/24) [RFC6811]. no ROA for AS 64511 and IP prefix 192.168.0.0/24) [RFC6811].
If routers ignore invalid BGP announcements, the minimal ROA above If routers ignore invalid BGP announcements, the minimal ROA above
ensures that the sub-prefix hijack will fail. ensures that the sub-prefix hijack will fail.
Thus, if a "minimal ROA" had been used, the attacker would be forced Thus, if a minimal ROA had been used, the attacker would be forced to
to launch a forged-origin prefix hijack in order to attract traffic, launch a forged-origin prefix hijack in order to attract traffic as
as follows: follows:
The hijacker AS 64511 sends a BGP announcement "192.168.0.0/16: AS The hijacker AS 64511 sends a BGP announcement "192.168.0.0/16: AS
64511, AS 64496", falsely claiming that AS 64511 is a neighbor of 64511, AS 64496", falsely claiming that AS 64511 is a neighbor of
AS 64496. AS 64496.
This forged-origin prefix hijack is significantly less damaging than This forged-origin prefix hijack is significantly less damaging than
the forged-origin sub-prefix hijack: the forged-origin sub-prefix hijack:
AS 64496 legitimately originates 192.168.0.0/16 in BGP, so the AS 64496 legitimately originates 192.168.0.0/16 in BGP, so the
hijacker AS 64511 is not presenting the only route to hijacker AS 64511 is not presenting the only route to
192.168.0.0/16. 192.168.0.0/16.
Moreover, the path originated by AS 64511 is one hop longer than Moreover, the path originated by AS 64511 is one hop longer than
the path originated by the legitimate origin AS 64496. the path originated by the legitimate origin AS 64496.
As discussed in [LSG16], this means that the hijacker will attract As discussed in [LSG16], this means that the hijacker will attract
less traffic than it would have in the forged-origin sub-prefix less traffic than it would have in the forged-origin sub-prefix
hijack, where the hijacker presents the only route to the hijacked hijack where the hijacker presents the only route to the hijacked
sub-prefix. sub-prefix.
In summary, a forged-origin sub-prefix hijack has the same impact as In summary, a forged-origin sub-prefix hijack has the same impact as
a regular sub-prefix hijack, despite the increased AS_PATH length of a regular sub-prefix hijack, despite the increased AS_PATH length of
the illegitimate route. A forged-origin sub-prefix hijack is also the illegitimate route. A forged-origin sub-prefix hijack is also
more damaging than the forged-origin prefix hijack. more damaging than the forged-origin prefix hijack.
4. Measurements of the RPKI 4. Measurements of the RPKI
Network measurements taken in June 2017 showed that 12% of the IP Network measurements taken in June 2017 showed that 12% of the IP
prefixes authorized in ROAs have a maxLength longer than their prefix prefixes authorized in ROAs have a maxLength value longer than their
length. Of these, the vast majority (84%) were non-minimal, as they prefix length. Of these, the vast majority (84%) were non-minimal,
included sub-prefixes that are not announced in BGP by the legitimate as they included sub-prefixes that are not announced in BGP by the
AS, and were thus vulnerable to forged-origin sub-prefix hijacks. legitimate AS and were thus vulnerable to forged-origin sub-prefix
See [GSG17] for details. hijacks. See [GSG17] for details.
These measurements suggest that operators commonly misconfigure the These measurements suggest that operators commonly misconfigure the
maxLength attribute, and unwittingly open themselves up to forged- maxLength attribute and unwittingly open themselves up to forged-
origin sub-prefix hijacks. That is, they are exposing a much larger origin sub-prefix hijacks. That is, they are exposing a much larger
attack surface for forged-origin hijacks than necessary. attack surface for forged-origin hijacks than necessary.
5. Recommendations about Minimal ROAs and maxLength 5. Recommendations about Minimal ROAs and maxLength
Operators SHOULD use "minimal ROAs" whenever possible. A minimal ROA Operators SHOULD use minimal ROAs whenever possible. A minimal ROA
contains only those IP prefixes that are actually originated by an AS contains only those IP prefixes that are actually originated by an AS
in BGP and no other IP prefixes. (See Section 3 for an example.) in BGP and no other IP prefixes. See Section 3 for an example.
In general, operators SHOULD avoid using the maxLength attribute in In general, operators SHOULD avoid using the maxLength attribute in
their ROAs, since its inclusion will usually make the ROA non- their ROAs, since its inclusion will usually make the ROA non-
minimal. minimal.
One such exception may be when all more specific prefixes permitted One such exception may be when all more specific prefixes permitted
by the maxLength are actually announced by the AS in the ROA. by the maxLength value are actually announced by the AS in the ROA.
Another exception is where: (a) the maxLength is substantially larger Another exception is where: (a) the maxLength value is substantially
compared to the specified prefix length in the ROA, and (b) a large larger compared to the specified prefix length in the ROA, and (b) a
number of more specific prefixes in that range are announced by the large number of more specific prefixes in that range are announced by
AS in the ROA. In practice, this case should occur rarely (if at the AS in the ROA. In practice, this case should occur rarely (if at
all). Operator discretion is necessary in this case. all). Operator discretion is necessary in this case.
This practice requires no changes to the RPKI specification and need This practice requires no changes to the RPKI specifications and need
not increase the number of signed ROAs in the RPKI because ROAs not increase the number of signed ROAs in the RPKI because ROAs
already support lists of IP prefixes [RFC6482]. See also [GSG17] for already support lists of IP prefixes [RFC6482]. See [GSG17] for
further discussion of why this practice will have minimal impact on further discussion of why this practice will have minimal impact on
the performance of the RPKI ecosystem. the performance of the RPKI ecosystem.
Operators implementing these recommendations and that have existing Operators that implement these recommendations and have existing ROAs
ROAs published in the RPKI system MUST perform a review of such published in the RPKI system MUST perform a review of such objects,
objects, especially where they make use of the maxLength attribute, especially where they make use of the maxLength attribute, to ensure
to ensure that the set of included prefixes is "minimal" with respect that the set of included prefixes is "minimal" with respect to the
to the current BGP origination and routing policies. Published ROAs current BGP origination and routing policies. Published ROAs MUST be
MUST be replaced as necessary. Such an exercise MUST be repeated replaced as necessary. Such an exercise MUST be repeated whenever
whenever the operator makes changes to either policy. the operator makes changes to either policy.
5.1. Facilitating Ad Hoc Routing Changes and DDoS Mitigation 5.1. Facilitating Ad Hoc Routing Changes and DDoS Mitigation
Operational requirements may require that a route for an IP prefix be Operational requirements may require that a route for an IP prefix be
originated on an ad hoc basis, with little or no prior warning. An originated on an ad hoc basis, with little or no prior warning. An
example of such a situation arises when an operator wishes to make example of such a situation arises when an operator wishes to make
use of DDoS mitigation services that use BGP to redirect traffic via use of DDoS mitigation services that use BGP to redirect traffic via
a "scrubbing center". a "scrubbing center".
In order to ensure that such ad hoc routing changes are effective, a In order to ensure that such ad hoc routing changes are effective, a
ROA validating the new route should exist. However a difficulty ROA validating the new route should exist. However, a difficulty
arises due to the fact that newly created objects in the RPKI are arises due to the fact that newly created objects in the RPKI are
made visible to relying parties considerably more slowly than routing made visible to relying parties considerably more slowly than routing
updates in BGP. updates in BGP.
Ideally, it would not be necessary to pre-create the ROA which Ideally, it would not be necessary to pre-create the ROA, which
validates the ad hoc route, and instead create it "on-the-fly" as validates the ad hoc route, and instead create it "on the fly" as
required. However, this is practical only if the latency imposed by required. However, this is practical only if the latency imposed by
the propagation of RPKI data is guaranteed to be within acceptable the propagation of RPKI data is guaranteed to be within acceptable
limits in the circumstances. For time-critical interventions such as limits in the circumstances. For time-critical interventions such as
responding to a DDoS attack, this is unlikely to be the case. responding to a DDoS attack, this is unlikely to be the case.
Thus, the ROA in question will usually need to be created well in Thus, the ROA in question will usually need to be created well in
advance of the routing intervention, but such a ROA will be non- advance of the routing intervention, but such a ROA will be non-
minimal, since it includes an IP prefix that is sometimes (but not minimal, since it includes an IP prefix that is sometimes (but not
always) originated in BGP. always) originated in BGP.
In this case, the ROA SHOULD include only: In this case, the ROA SHOULD only include:
(1) the set of IP prefixes that are always originated in BGP, and (1) the set of IP prefixes that are always originated in BGP, and
(2) the set of IP prefixes that are sometimes, but not always, (2) the set of IP prefixes that are sometimes, but not always,
originated in BGP. originated in BGP.
The ROA SHOULD NOT include any IP prefixes that the operator knows The ROA SHOULD NOT include any IP prefixes that the operator knows
will not be originated in BGP. In general, the ROA SHOULD NOT make will not be originated in BGP. In general, the ROA SHOULD NOT make
use of the maxLength attribute unless doing so has no impact on the use of the maxLength attribute unless doing so has no impact on the
set of included prefixes. set of included prefixes.
The running example is now extended to illustrate one situation where The running example is now extended to illustrate one situation where
it is not possible to issue a minimal ROA. it is not possible to issue a minimal ROA.
Consider the following scenario prior to the deployment of RPKI. Consider the following scenario prior to the deployment of RPKI.
Suppose AS 64496 announced 192.168.0.0/16 and has a contract with a Suppose AS 64496 announced 192.168.0.0/16 and has a contract with a
Distributed Denial of Service (DDoS) mitigation service provider that DDoS mitigation service provider that holds AS 64500. Further,
holds AS 64500. Further, assume that the DDoS mitigation service assume that the DDoS mitigation service contract applies to all IP
contract applies to all IP addresses covered by 192.168.0.0/22. When addresses covered by 192.168.0.0/22. When a DDoS attack is detected
a DDoS attack is detected and reported by AS 64496, AS 64500 and reported by AS 64496, AS 64500 immediately originates
immediately originates 192.168.0.0/22, thus attracting all the DDoS 192.168.0.0/22, thus attracting all the DDoS traffic to itself. The
traffic to itself. The traffic is scrubbed at AS 64500 and then sent traffic is scrubbed at AS 64500 and then sent back to AS 64496 over a
back to AS 64496 over a backhaul link. Notice that, during a DDoS backhaul link. Notice that, during a DDoS attack, the DDoS
attack, the DDoS mitigation service provider AS 64500 originates a mitigation service provider AS 64500 originates a /22 prefix that is
/22 prefix that is longer than AS 64496's /16 prefix, and so all the longer than AS 64496's /16 prefix, so all the traffic (destined to
traffic (destined to addresses in 192.168.0.0/22) that normally goes addresses in 192.168.0.0/22) that normally goes to AS 64496 goes to
to AS 64496 goes to AS 64500 instead. In some deployments, the AS 64500 instead. In some deployments, the origination of the /22
origination of the /22 route is performed by AS 64496 and announced route is performed by AS 64496 and announced only to AS 64500, which
only to AS 64500, which then announces transit for that prefix. This then announces transit for that prefix. This variation does not
variation does not change the properties considered here. change the properties considered here.
First, suppose the RPKI only had the minimal ROA for AS 64496, as First, suppose the RPKI only had the minimal ROA for AS 64496, as
described in Section 3. But if there is no ROA authorizing AS 64500 described in Section 3. However, if there is no ROA authorizing AS
to announce the /22 prefix, then the DDoS mitigation (and traffic 64500 to announce the /22 prefix, then the DDoS mitigation (and
scrubbing) scheme would not work. That is, if AS 64500 originates traffic scrubbing) scheme would not work. That is, if AS 64500
the /22 prefix in BGP during DDoS attacks, the announcement would be originates the /22 prefix in BGP during DDoS attacks, the
invalid [RFC6811]. announcement would be invalid [RFC6811].
Therefore, the RPKI should have two ROAs: one for AS 64496 and one Therefore, the RPKI should have two ROAs: one for AS 64496 and one
for AS 64500. for AS 64500.
ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496) ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496)
ROA:(192.168.0.0/22, AS 64500) ROA:(192.168.0.0/22, AS 64500)
Neither ROA uses the maxLength attribute. But the second ROA is not Neither ROA uses the maxLength attribute, but the second ROA is not
"minimal" because it contains a /22 prefix that is not originated by "minimal" because it contains a /22 prefix that is not originated by
anyone in BGP during normal operations. The /22 prefix is only anyone in BGP during normal operations. The /22 prefix is only
originated by AS 64500 as part of its DDoS mitigation service during originated by AS 64500 as part of its DDoS mitigation service during
a DDoS attack. a DDoS attack.
Notice, however, that this scheme does not come without risks. Notice, however, that this scheme does not come without risks.
Namely, all IP addresses in 192.168.0.0/22 are vulnerable to a Namely, all IP addresses in 192.168.0.0/22 are vulnerable to a
forged-origin sub-prefix hijack during normal operations, when the forged-origin sub-prefix hijack during normal operations when the /22
/22 prefix is not originated. (The hijacker AS 64511 would send the prefix is not originated. (The hijacker AS 64511 would send the BGP
BGP announcement "192.168.0.0/22: AS 64511, AS 64500", falsely announcement "192.168.0.0/22: AS 64511, AS 64500", falsely claiming
claiming that AS 64511 is a neighbor of AS 64500 and falsely claiming that AS 64511 is a neighbor of AS 64500 and falsely claiming that AS
that AS 64500 originates 192.168.0.0/22.) 64500 originates 192.168.0.0/22.)
In some situations, the DDoS mitigation service at AS 64500 might In some situations, the DDoS mitigation service at AS 64500 might
want to limit the amount of DDoS traffic that it attracts and scrubs. want to limit the amount of DDoS traffic that it attracts and scrubs.
Suppose that a DDoS attack only targets IP addresses in Suppose that a DDoS attack only targets IP addresses in
192.168.0.0/24. Then, the DDoS mitigation service at AS 64500 only 192.168.0.0/24. Then, the DDoS mitigation service at AS 64500 only
wants to attract the traffic designated for the /24 prefix that is wants to attract the traffic designated for the /24 prefix that is
under attack, but not the entire /22 prefix. To allow for this, the under attack, but not the entire /22 prefix. To allow for this, the
RPKI should have two ROAs: one for AS 64496 and one for AS 64500. RPKI should have two ROAs: one for AS 64496 and one for AS 64500.
ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496) ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496)
skipping to change at page 10, line 4 skipping to change at line 421
In some situations, the DDoS mitigation service at AS 64500 might In some situations, the DDoS mitigation service at AS 64500 might
want to limit the amount of DDoS traffic that it attracts and scrubs. want to limit the amount of DDoS traffic that it attracts and scrubs.
Suppose that a DDoS attack only targets IP addresses in Suppose that a DDoS attack only targets IP addresses in
192.168.0.0/24. Then, the DDoS mitigation service at AS 64500 only 192.168.0.0/24. Then, the DDoS mitigation service at AS 64500 only
wants to attract the traffic designated for the /24 prefix that is wants to attract the traffic designated for the /24 prefix that is
under attack, but not the entire /22 prefix. To allow for this, the under attack, but not the entire /22 prefix. To allow for this, the
RPKI should have two ROAs: one for AS 64496 and one for AS 64500. RPKI should have two ROAs: one for AS 64496 and one for AS 64500.
ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496) ROA:(192.168.0.0/16, 192.168.225.0/24, AS 64496)
ROA:(192.168.0.0/22-24, AS 64500) ROA:(192.168.0.0/22-24, AS 64500)
The second ROA uses the maxLength attribute because it is designed to The second ROA uses the maxLength attribute because it is designed to
explicitly enable AS 64500 to originate any /24 sub-prefix of explicitly enable AS 64500 to originate any /24 sub-prefix of
192.168.0.0/22. 192.168.0.0/22.
As before, the second ROA is not "minimal" because it contains As before, the second ROA is not "minimal" because it contains
prefixes that are not originated by anyone in BGP during normal prefixes that are not originated by anyone in BGP during normal
operations. As before, all IP addresses in 192.168.0.0/22 are operations. Also, all IP addresses in 192.168.0.0/22 are vulnerable
vulnerable to a forged-origin sub-prefix hijack during normal to a forged-origin sub-prefix hijack during normal operations when
operations, when the /22 prefix is not originated. the /22 prefix is not originated.
The use of maxLength in this second ROA also comes with additional The use of the maxLength attribute in this second ROA also comes with
risk. While it permits the DDoS mitigation service at AS 64500 to additional risk. While it permits the DDoS mitigation service at AS
originate prefix 192.168.0.0/24 during a DDoS attack in that space, 64500 to originate prefix 192.168.0.0/24 during a DDoS attack in that
it also makes the other /24 prefixes covered by the /22 prefix (i.e., space, it also makes the other /24 prefixes covered by the /22 prefix
192.168.1.0/24, 192.168.2.0/24, 192.168.3.0/24) vulnerable to forged- (i.e., 192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24) vulnerable
origin sub-prefix attacks. to forged-origin sub-prefix attacks.
5.2. Defensive De-aggregation In Response To Prefix Hijacks 5.2. Defensive De-aggregation in Response to Prefix Hijacks
In responding to certain classes of prefix hijack, in particular, the When responding to certain classes of prefix hijack (in particular,
forged-origin sub-prefix hijack described above, it may be desirable the forged-origin sub-prefix hijack described above), it may be
for the victim to perform "defensive de-aggregation", i.e. to begin desirable for the victim to perform "defensive de-aggregation", i.e.,
originating more-specific prefixes in order to compete with the to begin originating more-specific prefixes in order to compete with
hijack routes for selection as the best path in networks that are not the hijack routes for selection as the best path in networks that are
performing RPKI-based route origin validation (ROV) [RFC6811]. not performing RPKI-ROV [RFC6811].
In some topologies, where at least one AS on every path between the In topologies where at least one AS on every path between the victim
victim and hijacker filters ROV invalid prefixes, it may be the case and hijacker filters RPKI-ROV invalid prefixes, it may be the case
that the existence of a minimal ROA issued by the victim prevents the that the existence of a minimal ROA issued by the victim prevents the
defensive more-specific prefixes from being propagated to the defensive more-specific prefixes from being propagated to the
networks topologically close to the attacker, thus hampering the networks topologically close to the attacker, thus hampering the
effectiveness of this response. effectiveness of this response.
Nevertheless, this document recommends that where possible, network Nevertheless, this document recommends that, where possible, network
operators publish minimal ROAs even in the face of this risk. This operators publish minimal ROAs even in the face of this risk. This
is because: is because:
* Minimal ROAs offer the best possible protection against the * Minimal ROAs offer the best possible protection against the
immediate impact of such an attack, rendering the need for such a immediate impact of such an attack, rendering the need for such a
response less likely; response less likely;
* Increasing ROV adoption by network operators will, over time, * Increasing RPKI-ROV adoption by network operators will, over time,
decrease the size of the neighborhoods in which this risk exists; decrease the size of the neighborhoods in which this risk exists;
and and
* Other methods for reducing the size of such neighborhoods are * Other methods for reducing the size of such neighborhoods are
available to potential victims, such as establishing direct EBGP available to potential victims, such as establishing direct
adjacencies with networks from whom the defensive routes would External BGP (EBGP) adjacencies with networks from whom the
otherwise be hidden. defensive routes would otherwise be hidden.
6. Considerations for RTDR Filtering Scenarios 6. Considerations for RTDR Filtering Scenarios
Considerations related to ROAs and origin validation [RFC6811] for Considerations related to ROAs and RPKI-ROV [RFC6811] for the case of
the case of destination-based Remotely Triggered Discard Route (RTDR) destination-based RTDR (elsewhere referred to as "Remotely Triggered
(elsewhere referred to as "Remotely Triggered Black Hole") filtering Black Hole") filtering are addressed here. In RTDR filtering, highly
are addressed here. In RTDR filtering, highly specific prefixes specific prefixes (greater than /24 in IPv4 and greater than /48 in
(greater than /24 in IPv4 and greater than /48 in IPv6; possibly even IPv6, or possibly even /32 in IPv4 and /128 in IPv6) are announced in
/32 (IPv4) and /128 (IPv6)) are announced in BGP. These BGP. These announcements are tagged with the well-known BGP
announcements are tagged with the Well-known BGP Community defined by community defined by [RFC7999]. For the reasons set out above, it is
[RFC7999]. It is obviously not desirable to use a large maxLength or obviously not desirable to use a large maxLength value or include any
include any such highly specific prefixes in the ROAs to accommodate such highly specific prefixes in the ROAs to accommodate destination-
destination-based RTDR filtering, for the reasons set out above. based RTDR filtering.
As a result, RPKI-based route origin validation [RFC6811] is a poor As a result, RPKI-ROV [RFC6811] is a poor fit for the validation of
fit for the validation of RTDR routes. Specification of new RTDR routes. Specification of new procedures to address this use
procedures to address this use case through the use of the RPKI is case through the use of the RPKI is outside the scope of this
outside the scope of this document. document.
Therefore: Therefore:
* Operators SHOULD NOT create non-minimal ROAs (either by creating * Operators SHOULD NOT create non-minimal ROAs (by either creating
additional ROAs, or through the use of maxLength) for the purpose additional ROAs or using the maxLength attribute) for the purpose
of advertising RTDR routes; and of advertising RTDR routes; and
* Operators providing a means for operators of neighboring * Operators providing a means for operators of neighboring
autonomous systems to advertise RTDR routes via BGP MUST NOT make autonomous systems to advertise RTDR routes via BGP MUST NOT make
the creation of non-minimal ROAs a pre-requisite for its use. the creation of non-minimal ROAs a pre-requisite for its use.
7. User Interface Design Recommendations 7. User Interface Design Recommendations
Most operator interaction with the RPKI system when creating or Most operator interaction with the RPKI system when creating or
modifying ROAs will occur via a user interface that abstracts the modifying ROAs will occur via a user interface that abstracts the
underlying encoding, signing and publishing operations. underlying encoding, signing, and publishing operations.
This document recommends that designers and/or providers of such user This document recommends that designers and/or providers of such user
interfaces SHOULD provide warnings to draw the user's attention to interfaces SHOULD provide warnings to draw the user's attention to
the risks of creating non-minimal ROAs in general, and use of the the risks of creating non-minimal ROAs in general and using the
maxLength attribute in particular. maxLength attribute in particular.
Warnings provided by such a system may vary in nature from generic Warnings provided by such a system may vary in nature from generic
warnings based purely on the inclusion of the maxLength attribute, to warnings based purely on the inclusion of the maxLength attribute to
customised guidance based on the observable BGP routing policy of the customised guidance based on the observable BGP routing policy of the
operator in question. The choices made in this respect are expected operator in question. The choices made in this respect are expected
to be dependent on the target user audience of the implementation. to be dependent on the target user audience of the implementation.
8. Operational Considerations 8. Operational Considerations
The recommendations specified in this document, in particular, those The recommendations specified in this document (in particular, those
in Section 5, involve trade-offs between operational agility and in Section 5) involve trade-offs between operational agility and
security. security.
Operators adopting the recommended practice of issuing minimal ROAs Operators adopting the recommended practice of issuing minimal ROAs
will, by definition need to make changes to their existing set of will, by definition, need to make changes to their existing set of
issued ROAs in order to effect changes to the set of prefixes which issued ROAs in order to effect changes to the set of prefixes that
are originated in BGP. are originated in BGP.
Even in the case of routing changes that are planned in advance, Even in the case of routing changes that are planned in advance,
existing procedures may need to be updated to incorporate changes to existing procedures may need to be updated to incorporate changes to
issued ROAs, and may require additional time allowed for those issued ROAs and may require additional time allowed for those changes
changes to propagate. to propagate.
Operators are encouraged to carefully review the issues highlighted Operators are encouraged to carefully review the issues highlighted
(especially those in Section 5.1 and Section 5.2) in light of their (especially those in Sections 5.1 and 5.2) in light of their specific
specific operational requirements. Failure to do so could, in the operational requirements. Failure to do so could, in the worst case,
worst case, result in a self-inflicted denial of service. result in a self-inflicted denial of service.
The recommendations made in section 5 are likely to be more onerous The recommendations made in Section 5 are likely to be more onerous
for operators utilising large IP address space allocations from which for operators utilising large IP address space allocations from which
many more-specific advertisements are made in BGP. Operators of such many more-specific advertisements are made in BGP. Operators of such
networks are encouraged to seek opportunities to automate the networks are encouraged to seek opportunities to automate the
required procedures in order to minimise manual operational burden. required procedures in order to minimise manual operational burden.
9. Security Considerations 9. Security Considerations
This document makes recommendations regarding the use of RPKI-based This document makes recommendations regarding the use of RPKI-ROV as
origin validation as defined in [RFC6811], and as such introduces no defined in [RFC6811] and, as such, introduces no additional security
additional security considerations beyond those specified therein. considerations beyond those specified therein.
10. IANA Considerations 10. IANA Considerations
This document includes no request to IANA. This document has no IANA actions.
11. Acknowledgments
The authors would like to thank the following people for their review
and contributions to this document: Omar Sagga and Aris Lambrianidis.
Thanks are also due to Matthias Waehlisch, Ties de Kock, Amreesh
Phokeer, Eric Vyncke, Alvaro Retana, John Scudder, Roman Danyliw,
Andrew Alston, and Murray Kucherawy for comments and suggestions, to
Roni Even for the Gen-ART review, to Jean Mahoney for the ART-ART
review, to Acee Lindem for the Routing Directorate review, and to
Sean Turner for the Security Area Directorate review.
12. References 11. References
12.1. Normative References 11.1. Normative References
[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.
J., and E. Lear, "Address Allocation for Private J., and E. Lear, "Address Allocation for Private
Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918, Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918,
February 1996, <https://www.rfc-editor.org/info/rfc1918>. February 1996, <https://www.rfc-editor.org/info/rfc1918>.
[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>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
skipping to change at page 14, line 9 skipping to change at line 598
[RFC7115] Bush, R., "Origin Validation Operation Based on the [RFC7115] Bush, R., "Origin Validation Operation Based on the
Resource Public Key Infrastructure (RPKI)", BCP 185, Resource Public Key Infrastructure (RPKI)", BCP 185,
RFC 7115, DOI 10.17487/RFC7115, January 2014, RFC 7115, DOI 10.17487/RFC7115, January 2014,
<https://www.rfc-editor.org/info/rfc7115>. <https://www.rfc-editor.org/info/rfc7115>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
12.2. Informative References 11.2. Informative References
[GSG17] Gilad, Y., Sagga, O., and S. Goldberg, "Maxlength
Considered Harmful to the RPKI", in ACM CoNEXT 2017,
December 2017, <https://eprint.iacr.org/2016/1015.pdf>.
[LSG16] Lychev, R., Shapira, M., and S. Goldberg, "Rethinking
Security for Internet Routing", in Communications of the
ACM, October 2016, <http://cacm.acm.org/
magazines/2016/10/207763-rethinking-security-for-internet-
routing/>.
[GCHSS] Gilad, Y., Cohen, A., Herzberg, A., Schapira, M., and H. [GCHSS] Gilad, Y., Cohen, A., Herzberg, A., Schapira, M., and H.
Shulman, "Are We There Yet? On RPKI's Deployment and Shulman, "Are We There Yet? On RPKI's Deployment and
Security", in NDSS 2017, February 2017, Security", NDSS 2017, February 2017,
<https://eprint.iacr.org/2016/1010.pdf>. <https://eprint.iacr.org/2016/1010.pdf>.
[HARMFUL] Gilad, Y., Sagga, O., and S. Goldberg, "MaxLength [GSG17] Gilad, Y., Sagga, O., and S. Goldberg, "MaxLength
Considered Harmful to the RPKI", 2017, Considered Harmful to the RPKI", CoNEXT '17,
DOI 10.1145/3143361.3143363, December 2017,
<https://eprint.iacr.org/2016/1015.pdf>. <https://eprint.iacr.org/2016/1015.pdf>.
[LSG16] Lychev, R., Shapira, M., and S. Goldberg, "Rethinking
security for internet routing", Communications of the ACM,
DOI 10.1145/2896817, October 2016, <http://cacm.acm.org/
magazines/2016/10/207763-rethinking-security-for-internet-
routing/>.
[RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks [RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
Reserved for Documentation", RFC 5737, Reserved for Documentation", RFC 5737,
DOI 10.17487/RFC5737, January 2010, DOI 10.17487/RFC5737, January 2010,
<https://www.rfc-editor.org/info/rfc5737>. <https://www.rfc-editor.org/info/rfc5737>.
[RFC6907] Manderson, T., Sriram, K., and R. White, "Use Cases and [RFC6907] Manderson, T., Sriram, K., and R. White, "Use Cases and
Interpretations of Resource Public Key Infrastructure Interpretations of Resource Public Key Infrastructure
(RPKI) Objects for Issuers and Relying Parties", RFC 6907, (RPKI) Objects for Issuers and Relying Parties", RFC 6907,
DOI 10.17487/RFC6907, March 2013, DOI 10.17487/RFC6907, March 2013,
<https://www.rfc-editor.org/info/rfc6907>. <https://www.rfc-editor.org/info/rfc6907>.
[RFC7999] King, T., Dietzel, C., Snijders, J., Doering, G., and G. [RFC7999] King, T., Dietzel, C., Snijders, J., Doering, G., and G.
Hankins, "BLACKHOLE Community", RFC 7999, Hankins, "BLACKHOLE Community", RFC 7999,
DOI 10.17487/RFC7999, October 2016, DOI 10.17487/RFC7999, October 2016,
<https://www.rfc-editor.org/info/rfc7999>. <https://www.rfc-editor.org/info/rfc7999>.
[RFC8205] Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol [RFC8205] Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol
Specification", RFC 8205, DOI 10.17487/RFC8205, September Specification", RFC 8205, DOI 10.17487/RFC8205, September
2017, <https://www.rfc-editor.org/info/rfc8205>. 2017, <https://www.rfc-editor.org/info/rfc8205>.
Acknowledgments
The authors would like to thank the following people for their review
and contributions to this document: Omar Sagga and Aris Lambrianidis.
Thanks are also due to Matthias Waehlisch, Ties de Kock, Amreesh
Phokeer, Éric Vyncke, Alvaro Retana, John Scudder, Roman Danyliw,
Andrew Alston, and Murray Kucherawy for comments and suggestions, to
Roni Even for the Gen-ART review, to Jean Mahoney for the ART-ART
review, to Acee Lindem for the Routing Area Directorate review, and
to Sean Turner for the Security Area Directorate review.
Authors' Addresses Authors' Addresses
Yossi Gilad Yossi Gilad
Hebrew University of Jerusalem Hebrew University of Jerusalem
Rothburg Family Buildings, Edmond J. Safra Campus Rothburg Family Buildings
Edmond J. Safra Campus
Jerusalem 9190416 Jerusalem 9190416
Israel Israel
Email: yossigi@cs.huji.ac.il Email: yossigi@cs.huji.ac.il
Sharon Goldberg Sharon Goldberg
Boston University Boston University
111 Cummington St, MCS135 111 Cummington St, MCS135
Boston, MA 02215 Boston, MA 02215
United States of America United States of America
Email: goldbe@cs.bu.edu Email: goldbe@cs.bu.edu
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