Internet Engineering Task Force W. George
Internet-Draft Time Warner Cable
Intended status: Informational S. Murphy
Expires: January 11, 2014 SPARTA, Inc., a Parsons Company
July 10, 2013
BGPSec Considerations for AS Migration
draft-ietf-sidr-as-migration-00
Abstract
This draft discusses considerations and methods for supporting and
securing a common method for AS-Migration within the BGPSec protocol.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
1.2. Documentation note . . . . . . . . . . . . . . . . . . . 3
2. General Scenario . . . . . . . . . . . . . . . . . . . . . . 3
3. RPKI Considerations . . . . . . . . . . . . . . . . . . . . . 3
3.1. Origin Validation . . . . . . . . . . . . . . . . . . . . 4
3.2. Path Validation . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. Outbound announcements (PE-->CE) . . . . . . . . . . 5
3.2.2. Inbound announcements (CE-->PE) . . . . . . . . . . . 5
4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Outbound (PE->CE) . . . . . . . . . . . . . . . . . . . . 8
5.2. Inbound (CE->PE) . . . . . . . . . . . . . . . . . . . . 8
5.3. Other considerations . . . . . . . . . . . . . . . . . . 8
5.4. Example . . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
There is a method of managing an ASN migration using some BGP knobs
that, while commonly-used, are not formally part of the BGP4
[RFC4271] protocol specification and may be vendor-specific in exact
implementation. In order to ensure that this behavior is understood
and considered for future modifications to the BGP4 protocol
specification, especially as it concerns the handling of AS_PATH
attributes, the behavior and process has been described in draft-ga-
idr-as-migration [I-D.ga-idr-as-migration]. Accordingly, it is
necessary to discuss this de facto standard to ensure that the
process and features are properly supported in BGPSec
[I-D.ietf-sidr-bgpsec-protocol], because BGPSec is explicitly
designed to protect against changes in the BGP AS_PATH, whether by
choice, by misconfiguration, or by malicious intent. It is critical
that the BGPSec protocol framework is able to support this
operationally necessary tool without creating an unacceptable
security risk or exploit in the process.
1.1. Requirements Language
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
1.2. Documentation note
This draft uses Autonomous System Numbers (ASNs) from the range
reserved for documentation as described in RFC 5398 [RFC5398]. In
the examples used here, they are intended to represent Globally
Unique ASNs, not private ASNs as documented in RFC 1930 [RFC1930]
section 10.
2. General Scenario
This draft assumes that the reader has read and understood the ASN
migration method discussed in draft-ga-idr-as-migration
[I-D.ga-idr-as-migration] including its examples, as they will be
heavily referenced here. The use case being discussed in the
referenced draft is as follows: For whatever the reason, a provider
is in the process of merging two or more ASNs, where eventually one
subsumes the other(s). Confederations RFC 5065 [RFC5065] are *not*
being implemented between the ASNs, but vendor-specific configuration
knobs are being used to allow the migrating PE to masquerade as the
old ASN for the PE-CE eBGP session, or to manipulate the AS_PATH, or
both. While BGPSec [I-D.ietf-sidr-bgpsec-protocol] does have a case
to handle standard confederation implementations, it is not
applicable in this exact case. The reason that this migration drives
a slightly different solution in BGPSec than a standard confederation
is that unlike in a confederation, eBGP peers may not be peering with
the "correct" external ASN, and the forward-signed updates are for a
public ASN, rather than a private one, so there is no expectation
that the BGP speaker should strip the affected signatures before
propagating the route to its eBGP neighbors.
In the following examples, AS64510 is being subsumed by AS64500, and
both ASNs represent a Service Provider (SP) network (see Figure 1 in
draft-ga-idr-as-migration [I-D.ga-idr-as-migration]). AS64496 and
64499 represent end customer networks. References to PE, CE, and P
routers mirror the diagrams and references in the above cited draft.
3. RPKI Considerations
Since the methods and implementation discussed in draft-ga-idr-as-
migration [I-D.ga-idr-as-migration] are not technically a part of the
BGP4 protocol implementation, but rather a vendor-specific feature,
BGPSec is not technically required to ensure that it continues
functioning as it does today. However, this is widely used during
network integrations resulting from mergers and acquisitions, as well
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as network redesigns, and therefore it is not feasible to simply
eliminate this capability on any BGPSec-enabled routers/ASNs. What
follows is a discussion of the potential issues to be considered
regarding how ASN-migration and BGPSec
[I-D.ietf-sidr-bgpsec-protocol] validation might interact.
One of the primary considerations for this draft and migration is
that companies rarely stop after one merger/acquisition/divestiture,
and end up accumulating several legacy ASNs over time. Since they
are using methods to migrate that do not require coordination with
customers, they do not have a great deal of control over the length
of the transition period as they might with something completely
under their administrative control (e.g. a key roll). This leaves
many SPs with multiple legacy ASNs which don't go away very quickly,
if at all. As solutions were being proposed for RPKI implementations
to solve this transition case, operational complexity and hardware
scaling considerations associated with maintaining multiple legacy
ASN keys on routers throughout the combined network have been
carefully considered. While SPs SHOULD NOT remain in this transition
phase indefinitely because of the operational complexity and scaling
considerations associated with maintaining multiple legacy ASN keys
on routers throughout the combined network, this is of limited
utility as a solution, and so every effort has been made to keep the
additional complexity during the transition period to a minimum, on
the assumption that it will likely be protracted.
3.1. Origin Validation
Origin Validation does not need a unique solution to enable
migration, as the existing protocol and procedure allows for a
solution. In the scenario discussed, AS64510 is being replaced by
AS64500. If there are any existing routes originated by AS64510 on
the router being moved into the new ASN, this simply requires
generating new ROAs for the routes with the new ASN and treating them
as new routes to be added to AS64500. However, we also need to
consider the situation where one or more other PEs are still in
AS64510, and are originating one or more routes that may be distinct
from any that the router under migration is originating. PE1 (which
is now a part of AS64500 and instructed to use replace-as to remove
AS64510 from the path) needs to be able to properly handle routes
originated from AS64510. If the route now shows up as originating
from AS64500, any downstream peers' validation check will fail unless
a ROA is *also* available for AS64500 as the origin ASN, meaning that
there will be overlapping ROAs until all routers originating prefixes
from AS64510 are migrated to AS64500. Overlapping ROAs are
permissible perRFC 6480 [RFC6480] section 3.2, and so managing origin
validation during a migration like this is merely applying the
defined case where a set of prefixes are originated from more than
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one ASN. Therefore, for each ROA that authorizes AS64510 to
originate a prefix, a new ROA SHOULD also be created that authorizes
AS64500 to originate the same prefix.
3.2. Path Validation
BGPSec Path Validation requires that each router in the AS Path
cryptographically sign its update to assert that "Every AS on the
path of ASes through which the update message passes has explicitly
authorized the advertisement of the route to the subsequent AS in the
path." (see point #2 in intro of [I-D.ietf-sidr-bgpsec-protocol])
Since the referenced AS migration technique is explicitly modifying
the AS_PATH between two eBGP peers who are not coordinating with one
another (are not in the same administrative domain), no level of
trust can be assumed, and therefore it may be difficult to identify
legitimate manipulation of the AS_PATH for migration activities when
compared to manipulation due to misconfiguration or malicious intent.
3.2.1. Outbound announcements (PE-->CE)
When PE1 is moved from AS64510 to AS64500, it will be provisioned
with the appropriate keys for AS64500 to allow it to forward-sign
routes using AS64500. However, there is currently no guidance in the
BGPSec protocol specification on whether or not the forward-signed
ASN value MUST match the configured "remote-as" to validate properly.
That is, if CE1's BGP session is configured as "remote-as 64510", the
presence of "local-as 64510" on PE1 will ensure that there is no ASN
mismatch on the BGP session itself, but if CE1 receives updates from
its remote neighbor (PE1) forward-signed from AS64500, there is no
guidance as to whether the BGPSec validator on CE1 still consider
those valid by default. RFC4271 [RFC4271] section 6.3 mentions this
match between the ASN of the peer and the AS_PATH data, but it is
listed as an optional validation, rather than a requirement.
Assuming that this mismatch will be allowed by vendor implementations
and using it as a means to solve this migration case is likely to be
problematic.
3.2.2. Inbound announcements (CE-->PE)
Inbound is more complicated, because the CE doesn't know that PE1 has
changed ASNs, so it is forward-signing all of its routes with
AS64510, not AS64500. The BGPSec speaker cannot manipulate previous
signatures, and therefore cannot manipulate the previous AS Path
without causing a mismatch that will invalidate the route. If the
updates are simply left intact, the ISP would still need to publish
and maintain valid and active public-keys for AS 64510 if it is to
appear in the BGPSec_Path_Signature in order that receivers can
validate the BGPSEC_Path_Signature arrived intact/whole. However, if
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the updates are left intact, this will cause the AS Path length to be
increased, which is undesirable as discussed in draft-ga-idr-as-
migration [I-D.ga-idr-as-migration].
4. Requirements
These requirements are written under the assumption that the
currently vendor-specific implementations will be standardized via
draft-ga-idr-as-migration [I-D.ga-idr-as-migration], as it makes
little sense to build support into a standard for something that is
not actually a standard itself. However, should IETF choose not to
standardize the discussed method of AS migration, it is possible that
this draft could be considered implementation guidance for those
vendors that have support for this method of AS migration and wish to
support it in their BGPSec implementation. In order to be
deployable, any solution to the described problem needs to consider
the following requirements, listed in no particular order:
o BGPSec MUST support AS Migration for both inbound and outbound
route announcements (see Section 3.2.1 and 3.2.2). It SHOULD do
this without reducing BGPSec's protections for route path
o MUST NOT require any reconfiguration on the remote eBGP neighbor
(CE)
o SHOULD confine configuration changes to the migrating PEs e.g.
can't require global configuration changes to support migration
o MUST NOT lengthen AS Path during migration
o MUST operate within existing trust boundaries e.g. can't expect
remote side to accept pCount=0 (see Section 3 of
[I-D.ietf-sidr-bgpsec-protocol]) from untrusted/non-confed
neighbor
5. Solution
As noted in [I-D.ietf-sidr-bgpsec-protocol], section 4.2, BGPSec
already has a solution for hiding ASNs where increasing the AS Path
length is undesirable. So one might think that a simple solution
would be to retain the keys for AS64510 on PE1, and forward-sign
towards CE1 with AS64510 and pCount=0. However, this would mean
passing a pCount=0 between two ASNs that are in different
administrative and trust domains such that it could represent a
significant attack vector to manipulate BGPSec-signed paths. The
expectation for legitimate instances of pCount=0 (to make a route-
server that is not part of the transit path invisible) is that there
is some sort of existing trust relationship between the operators of
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the route-server and the downstream peers such that the peers could
be explicitly configured by policy to accept pCount=0 announcements
only on the sessions where they are expected. For the same reason
that things like local-as are used for ASN migration without end
customer coordination, it is unrealistic to assume any sort of
coordination between the SP and the administrators of CE1 to ensure
that they will by policy accept pCount=0 signatures during the
transition period, and therefore this is not a workable solution.
A better solution presents itself when considering how to handle
routes coming from the CE toward the PE, where the routes are
forward-signed to AS64510, but will eventually need to show AS64500
in the outbound route announcement. Because both AS64500 and AS64510
are in the same administrative domain, a signature from AS64510
forward-signed to AS64500 with pCount=0 would be acceptable as it
would be within the appropriate trust boundary so that each BGP
speaker could be explicitly configured to accept pCount=0 where
appropriate between the two ASNs. At the very simplest, this could
potentially be used at the eBGP boundary between the two ASNs during
migration. Since the AS_PATH manipulation described above usually
happens at the PE router on a per-session basis, and does not happen
network-wide simultaneously, it is not generally appropriate to apply
this AS hiding technique across all routes exchanged between the two
ASNs, as it may result in routing loops and other undesirable
behavior. Therefore the most appropriate place to implement this is
on the local PE that still has eBGP sessions associated with AS64510
(using the transition knobs detailed in the companion draft). Since
that PE has been moved to AS64500, it is not possible for it to
forward-sign AS64510 with pCount=0 without some minor changes to the
BGPSec implementation to address this use case.
AS migration is using AS_PATH and remote-AS manipulation to act as if
a PE under migration exists simultaneously in both ASNs even though
it is only configured with one global ASN. This draft proposes
applying a similar technique to the BGPSec signatures generated for
routing updates processed through this migration machinery. Each
routing update that is received from or destined to an eBGP neighbor
that is still using the old ASN (64510) will be signed twice, once
with the ASN to be hidden and once with the ASN that will remain
visible. In essence, we are treating the update as if the PE had an
internal BGP hop and the update was passed across an eBGP session
between AS64500 and AS64510, configured to use and accept pCount=0,
while eliminating the processing and storage overhead of creating an
actual eBGP session between the two ASNs within the PE router. This
will result in a properly secured AS Path in the affected route
updates, because the PE router will be provisioned with valid keys
for both AS64500 and AS64510. An important distinction here is that
while AS migration under standard BGP4 is manipulating the AS_PATH
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attribute, BGPSec uses an attribute called the Secure_Path (see
Section 3 of [I-D.ietf-sidr-bgpsec-protocol]), and BGPSec capable
neighbors do not exchange AS_PATH information in their route
announcements. However, a BGPSec neighbor peering with a non-BGPSec-
capable neighbor will use the information found in Secure_Path to
reconstruct a standard AS_PATH for updates sent to that neighbor.
Unlike in Secure_Path where the ASN to be hidden is still present,
but ignored when considering AS Path (due to pCount=0), when
reconstructing an AS_PATH for a non-BGPSec neighbor, the pCount=0
ASNs will not appear in the AS_PATH at all (see section 4.4 of the
above-referenced draft). This draft is not changing existing AS_PATH
reconstruction behavior, merely highlighting it for clarity.
The procedure to support AS Migration in BGPSec is slightly different
depending on whether the PE under migration is receiving the routes
from one of its eBGP peers ("inbound" as in section 3.2.2) or
destined toward the eBGP peers ("outbound" as in section 3.2.1).
5.1. Outbound (PE->CE)
When a PE router receives an update destined for an eBGP neighbor
that is locally configured with AS-migration knobs as discussed in
draft-ga-idr-as-migration [I-D.ga-idr-as-migration], it MUST generate
a valid BGPSec signature as defined in
[I-D.ietf-sidr-bgpsec-protocol] for _both_ configured ASNs. It MUST
generate a signature from the new (global) ASN forward signing to the
old (local) ASN with pCount=0, and then it MUST generate a forward
signature from the old (local) ASN to the target eBGP ASN with
pCount=1 as normal.
5.2. Inbound (CE->PE)
When a PE router receives an update from an eBGP neighbor that is
locally configured with AS-migration knobs (i.e. the opposite
direction of the previous route flow), it MUST generate a signature
from the old (local) ASN forward signing to the new (global) ASN with
pCount=0. It is not necessary to generate the second signature from
the new (global) ASN because the ASBR will generate that when it
forward signs towards its eBGP peers as defined in normal BGPSec
operation. This is a deviation from standard BGPSec behavior in that
typically a signature is not added when a routing update is sent
across an iBGP session, and the next signature is added by the ASBR
when it forward-signs toward its eBGP peer as the routing update
exits the ASN.
5.3. Other considerations
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In this case, the PE is adding BGPSec attributes to routes received
from or destined to an iBGP neighbor, and using pCount=0 to mask
them. While this is not prohibited by the current BGPSec
specification, routers that receive updates from iBGP neighbors MUST
NOT reject updates with new (valid) BGPSec attributes, including the
presence of pCount=0 on a previous signature, or they will interfere
with this implementation. In similar fashion, any route-reflectors
in the path of these updates MUST reflect them transparently to their
clients.
In order to secure this set of signatures, the PE router MUST be
provisioned with valid keys for _both_ configured ASNs (old and new),
and the key for the old ASN MUST be kept valid until all eBGP
sessions are migrated to the new ASN. Downstream neighbors will see
this as a valid BGPSec path, as they will simply trust that their
upstream neighbor accepted pCount=0 because it was explicitly
configured to do so based on a trust relationship and business
relationship between the upstream and its neighbor (the old and new
ASNs).
5.4. Example
The following example will illustrate the method being used above.
As with previous examples, PE1 is the router being migrated, AS64510
is the old AS, which is being subsumed by AS64500, the "keep" AS.
64505 is another external peer, used to demonstrate what the
announcements will look like to a third party peer that is not part
of the migration. Some additional notation is used to delineate the
details of each signature as follows:
The origin BGPSEC signature attribute takes the form: sig(<Target
ASN>, Origin ASN, pCount, NLRI Prefix) key
Intermediate BGPSEC signature attributes take the form: sig(<Target
ASN>, Signer ASN, pCount, <most recent sig field>) key
Equivalent AS_PATH refers to what the AS_PATH would look like if it
was reconstructed to be sent to a non-BGPSec peer, while Secure_Path
shows the AS Path as represented between BGPSec peers.
Note: The representation of signature attribute generation is being
simplified here somewhat for the sake of brevity; the actual details
of the signing process are as described Sections 4.1 and 4.2 in
[I-D.ietf-sidr-bgpsec-protocol]. For example, what is covered by the
signature also includes Flags, Algorithm Suite ID, NLRI length, etc.
Also, the key is not carried in the update, instead the SKI is
carried.
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Before Merger
64505
|
ISP B ISP A
CE-1 <--- PE-1 <------------------- PE-2 <--- CE-2
64496 Old_ASN: 64510 Old_ASN: 64500 64499
CE-2 to PE-2: sig(<64500>, O=64499, pCount=1, N)K_64499-CE2 [sig1]
Equivalent AS_PATH=(64499)
Secure_Path=(64499)
length=sum(pCount)=1
PE-2 to 64505: sig(<64505>, 64500, pCount=1, <sig1>)K_64500-PE2 [sig2]
sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig1]
Equivalent AS_PATH=(64500,64499)
Secure_Path=(64500,64499)
length=sum(pCount)=2
PE-2 to PE-1: sig(<64510>, 64500, pCount=1, <sig1>)K_64500-PE2 [sig3]
sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig1]
Equivalent AS_PATH=(64500,64499)
Secure_Path=(64500,64499)
length=sum(pCount)=2
PE-1 to CE-1: sig(<64496>, 64510, pCount=1, <sig3>)K_64510-PE1 [sig4]
sig(<64510>, 64500, pCount=1, <sig1>)K_64500-PE2 [sig3]
sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig1]
Equivalent AS_PATH= (64510,64500,64499)
Secure_Path=(64510,64500,64499)
length=sum(pCount)=3
Migrating, route flow outbound PE-1 to CE-1
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64505
|
ISP A' ISP A'
CE-1 <--- PE-1 <------------------- PE-2 <--- CE-2
64496 Old_ASN: 64510 Old_ASN: 64500 64499
New_ASN: 64500 New_ASN: 64500
CE-2 to PE-2: sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig11]
Equivalent AS_PATH=(64499)
Secure_Path=(64499)
length=sum(pCount)=1
PE-2 to 64505: sig(<64505>, 64500, pCount=1, <sig11>)K_64500-PE2 [sig12]
sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig11]
Equivalent AS_PATH=(64500,64499)
Secure_Path=(64500,64499)
length=sum(pCount)=2
PE-2 to PE-1: sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig11]
Equivalent AS_PATH=(64499)
Secure_Path=(64499)
length=sum(pCount)=1
#PE-2 sends to PE-1 (in iBGP) the exact same update as received from AS64499.
PE-1 to CE-1: sig(<64496>, 64510, pCount=1, <sig13>)K_64510-PE1 [sig14]
sig(<64510>, 64500, pCount=0, <sig11>)K_64500-PE2 [sig13]
sig(<64500>, 64499, pCount=1, N)K_64499-CE2 [sig11]
Equivalent AS_PATH=(64510,64499)
Secure_Path=(64510, 64500(pCount=0),64499)
length=sum(pCount)=2 (length is NOT 3)
#PE1 adds [sig13] acting as AS64500
#PE1 accepts [sig13] with pCount=0 acting as AS64510,
#as it would if it received sig13 from an eBGP peer
Migrating, route flow inbound CE-1 to PE-1
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64505
|
ISP A' ISP A'
CE-1 ---> PE-1 -------------------> PE-2 ---> CE-2
64496 Old_ASN: 64510 Old_ASN: 64500 64499
New_ASN: 64500 New_ASN: 64500
CE-1 to PE-1: sig(<64510>, 64496, pCount=1, N)K_64496-CE1 [sig21]
Equivalent AS_PATH=(64496)
Secure_Path=(64496)
length=sum(pCount)=1
PE-1 to PE-2: sig(<64500>, 64510, pCount=0, <sig21>)K_64510-PE1 [sig22]
sig(<64510>, 64496, pCount=1, N)K_64496-CE1 [sig21]
Equivalent AS_PATH=(64496)
Secure_Path=(64510 (pCount=0),64496)
length=sum(pCount)=1 (length is NOT 2)
#PE1 adds [sig22] acting as AS64510
#PE1 accepts [sig22] with pCount=0 acting as AS64500,
#as it would if it received sig22 from an eBGP peer
PE-2 to 64505: sig(<64505>, 64500, pCount=1, <sig22>)K_64500-PE2 [sig23]
sig(<64500>, 64510, pCount=0, <sig21>)K_64510-PE1 [sig22]
sig(<64510>, 64496, pCount=1, N)K_64496-CE1 [sig21]
Equivalent AS_PATH=(64500,64496)
Secure_Path=(64500,64510 (pCount=0), 64496)
length=sum(pCount)=2 (length is NOT 3)
PE-2 to CE-2: sig(<64499>, 64500, pCount=1, <sig22>)K_64500-PE2 [sig24]
sig(<64500>, 64510, pCount=0, <sig21>)K_64510-PE1 [sig22]
sig(<64510>, 64496, pCount=1, N)K_64496-CE1 [sig21]
Equivalent AS_PATH=(64500,64496)
Secure_Path=(64500, 64510 (pCount=0), 64496)
length=sum(pCount)=2 (length is NOT 3)
6. Acknowledgements
Thanks to Kotikalapudi Sriram, Shane Amante, Warren Kumari, and Terry
Manderson for their review comments.
Additionally, the solution presented in this draft is an amalgam of
several SIDR interim meeting discussions plus a discussion at IETF85,
collected and articulated thanks to Sandy Murphy.
7. IANA Considerations
George & Murphy Expires January 11, 2014 [Page 12]
Internet-Draft as-migration July 2013
This memo includes no request to IANA.
8. Security Considerations
This draft discusses a process by which one ASN is migrated into and
subsumed by another. Because this process involves manipulating the
AS_Path in a BGP route to make it deviate from the actual path that
it took through the network, this migration process is attempting to
do exactly what BGPSec is working to prevent. BGPSec MUST be able to
manage this legitimate use of AS_Path manipulation without generating
a vulnerability in the RPKI route security infrastructure.
The solution discussed above is considered to be reasonably secure
from exploitation by a malicious actor because it requires both
signatures to be secured as if they were forward-signed between two
eBGP neighbors. This requires any router using this solution to be
provisioned with valid keys for both the migrated and subsumed ASN so
that it can generate valid signatures for each of the two ASNs it is
adding to the path. If the AS's keys are compromised, or zero-length
keys are permitted, this does potentially enable an AS_PATH
shortening attack, but this is not fundamentally altering the
existing security risks for BGPSec.
9. References
9.1. Normative References
[I-D.ga-idr-as-migration]
George, W. and S. Amante, "Autonomous System (AS)
Migration Features and Their Effects on the BGP AS_PATH
Attribute", draft-ga-idr-as-migration-01 (work in
progress), February 2013.
[I-D.ietf-sidr-bgpsec-protocol]
Lepinski, M., "BGPSEC Protocol Specification", draft-ietf-
sidr-bgpsec-protocol-07 (work in progress), February 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5398] Huston, G., "Autonomous System (AS) Number Reservation for
Documentation Use", RFC 5398, December 2008.
George & Murphy Expires January 11, 2014 [Page 13]
Internet-Draft as-migration July 2013
9.2. Informative References
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, March 1996.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous
System Confederations for BGP", RFC 5065, August 2007.
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, February 2012.
Authors' Addresses
Wesley George
Time Warner Cable
13820 Sunrise Valley Drive
Herndon, VA 20171
US
Phone: +1 703-561-2540
Email: wesley.george@twcable.com
Sandy Murphy
SPARTA, Inc., a Parsons Company
7110 Samuel Morse Drive
Columbia, MD 21046
US
Phone: +1 443-430-8000
Email: sandy@tislabs.com
George & Murphy Expires January 11, 2014 [Page 14]
