LISP-Security (LISP-SEC)Cisco Systems170 Tasman DriveSan Jose95134CaliforniaUSAfmaino@cisco.comCisco Systems170 Tasman DriveSan Jose95134CaliforniaUSAvermagan@cisco.comTechnical University of Cataloniac/ Jordi Girona s/nBarcelona08034Spainacabello@ac.upc.eduUniversite catholique de LouvainPlace St. Barbe 2Louvain-la-NeuveBelgiumdamien.saucez@uclouvain.beUniversite catholique de LouvainPlace St. Barbe 2Louvain-la-NeuveBelgiumolivier.bonaventure@uclouvain.be
Internet
Network Working GroupLISP; deploymentThis memo specifies LISP-SEC, a set of security mechanisms that
provide origin authentication, integrity and anti-replay protection to
LISP's EID-to-RLOC mapping data conveyed via mapping lookup process.
LISP-SEC also enables verification of authorization on EID-prefix claims
in Map-Reply messages.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 .The Locator/ID Separation Protocol defines a set of functions for routers to
exchange information used to map from non-routable Endpoint Identifiers
(EIDs) to routable Routing Locators (RLOCs). If these EID-to-RLOC
mappings, carried through Map-Reply messages, are transmitted without
integrity protection, an adversary can manipulate them and hijack the
communication, impersonate the requested EID or mount Denial of Service
or Distributed Denial of Service attacks. Also, if the Map-Reply message
is transported unauthenticated, an adversarial LISP entity can overclaim
an EID-prefix and maliciously redirect traffic directed to a large
number of hosts. A detailed description of "overclaiming" attack is
provided in .This memo specifies LISP-SEC, a set of security mechanisms that
provide origin authentication, integrity and anti-replay protection to
LISP's EID-to-RLOC mapping data conveyed via mapping lookup process.
LISP-SEC also enables verification of authorization on EID-prefix claims
in Map-Reply messages, ensuring that the sender of a Map-Reply that
provides the location for a given EID-prefix is entitled to do so
according to the EID prefix registered in the associated Map Server.
Map-Register security, including the right for a LISP entity to register
an EID-prefix or to claim presence at an RLOC, is out of the scope of
LISP-SEC. Additional security considerations are described in Section
6.One-Time Key (OTK): An ephemeral randomly generated key that must
be used for a single Map-Request/Map-Reply exchange.ITR-OTK: The One-Time Key generated at the ITR.MS-OTK: The One-Time Key generated at the Map-Server.Encapsulated Control Message (ECM): A LISP control message
that is prepended with an additional LISP header. ECM is used by
ITRs to send LISP control messages to a Map-Resolver, by
Map-Resolvers to forward LISP control messages to a Map-Server, and
by Map-Resolvers to forward LISP control messages to an ETR.Authentication Data (AD): Metadata that is included either in a
LISP ECM header or in a Map-Reply message to support
confidentiality, integrity protection, and verification of
EID-prefix authorization.OTK-AD: The portion of ECM Authentication Data that contains
a One-Time Key.EID-AD: The portion of ECM and Map-Reply Authentication Data
used for verification of EID-prefix authorization.PKT-AD: The portion of Map-Reply Authentication Data used to
protect the integrity of the Map-Reply message.For definitions of other terms, notably Map-Request, Map-Reply,
Ingress Tunnel Router (ITR), Egress Tunnel Router (ETR), Map-Server (MS)
and Map-Resolver (MR) please consult the LISP specification .LISP-SEC addresses the control plane threats, described in , that target EID-to-RLOC
mappings, including manipulations of Map-Request and Map-Reply messages,
and malicious xTR EID overclaiming. However LISP-SEC makes two main
assumptions that are not part of . First, the LISP Mapping System
is expected to deliver Map-Request messages to their intended
destinations as identified by the EID. Second, no man-in-the-middle
attack can be mounted within the LISP Mapping System. Furthermore, while
LISP-SEC enables detection of EID prefix over claiming attacks, it
assumes that Map Servers can verify the EID prefix authorization at time
of registration.Accordingly to the threat model described in LISP-SEC assumes that any kind of
attack, including MITM attacks, can be mounted in the access network,
outside of the boundaries of the LISP mapping system. An on-path
attacker, outside of the LISP mapping service system can, for instance,
hijack mapping requests and replies, spoofing the identity of a LISP
node. Another example of on-path attack, called over claiming attack,
can be mounted by a malicious Egress Tunnel Router (ETR), by over
claiming the EID-prefixes for which it is authoritative. In this way the
ETR can maliciously redirect traffic directed to a large number of
hosts.The goal of the security mechanisms defined in is to prevent unauthorized insertion of
mapping data, by providing origin authentication and integrity
protection for the Map-Registration, and by using the nonce to detect
unsolicited Map-Reply sent by off-path attackers.LISP-SEC builds on top of the security mechanisms defined in to address the threats described in by leveraging the trust relationships
existing among the LISP entities participating to the exchange of the
Map-Request/Map-Reply messages. Those trust relationships are used to
securely distribute a One-Time Key (OTK) that provides origin
authentication, integrity and anti-replay protection to mapping data
conveyed via the mapping lookup process, and that effectively prevent
over claiming attacks. The processing of security parameters during the
Map-Request/Map-Reply exchange is as follows:The ITR-OTK is generated and stored at the ITR, and securely
transported to the Map-Server.The Map-Server uses the ITR-OTK to compute an HMAC that protects
the integrity of the mapping data provided by the Map-Server to
prevent overclaiming attacks. The Map-Server also derives a new OTK
(MS-OTK) that is passed to the ETR, by applying a Key Derivation
Function (KDF) to the ITR-OTK.The ETR uses the MS-OTK to compute an HMAC that protects the
integrity of the Map-Reply sent to the ITR.Finally, the ITR uses the stored ITR-OTK to verify the integrity
of the mapping data provided by both the Map-Server and the ETR, and
to verify that no overclaiming attacks were mounted along the path
between the Map-Server and the ITR. provides the detailed description of the
LISP-SEC control messages and their processing, while the rest of this
section describes the flow of protocol operations at each entity
involved in the Map-Request/Map-Reply exchange:The ITR, upon transmitting a Map-Request message, generates and
stores an OTK (ITR-OTK). This key is included into the Encapsulated
Control Message (ECM) that contains the Map-Request sent to the
Map-Resolver. To provide confidentiality to the ITR-OTK over the
path between the ITR and its Map-Resolver, the ITR-OTK SHOULD be
encrypted using a preconfigured key shared between the ITR and the
Map-Resolver, similar to the key shared between the ETR and the
Map-Server in order to secure ETR registration .The Map-Resolver decapsulates the ECM message, decrypts the
ITR-OTK, if needed, and forwards through the Mapping System the
received Map-Request and the ITR-OTK, as part of a new ECM message.
As described in , the LISP
Mapping System delivers the ECM to the appropriate Map-Server, as
identified by the EID destination address of the Map-Request.The Map-Server is configured with the location mappings and
policy information for the ETR responsible for the destination EID
address. Using this preconfigured information the Map-Server, after
the decapsulation of the ECM message, finds the longest match
EID-prefix that covers the requested EID in the received
Map-Request. The Map-Server adds this EID-prefix, together with an
HMAC computed using the ITR-OTK, to a new Encapsulated Control
Message that contains the received Map-Request.The Map-Server derives a new OTK (MS-OTK) by applying a Key
Derivation Function (KDF) to the ITR-OTK. MS-OTK is included in the
Encapsulated Control Message sent to the ETR. To provide MS-OTK
confidentiality over the path between the Map-Server and the ETR,
the MS-OTK should be encrypted using the key shared between the ETR
and the Map-Server in order to secure ETR registration .If the Map-Server is acting in proxy mode, as specified in , the ETR is not involved in the
generation of the Map-Reply. In this case the Map-Server generates
the Map-Reply on behalf of the ETR as described below.The ETR, upon receiving the Encapsulated Map-Request from the
Map-Server, decrypts the MS-OTK, if needed, and originates a
Map-Reply that contains the EID-to-RLOC mapping information as
specified in .The ETR computes an HMAC over the original LISP Map-Reply, keyed
with MS-OTK to protect the integrity of the whole Map-Reply. The ETR
also copies the EID-prefix authorization data that the Map-Server
included in the Encapsulated Map-Request into the Map-Reply
message.The ITR, upon receiving the Map-Reply, uses the locally stored
ITR-OTK to verify the integrity of the EID-prefix authorization data
included in the Map-Reply by the Map-Server. The ITR computes the
MS-OTK by applying the same KDF used by the Map-Server, and verifies
the integrity of the Map-Reply. If the integrity checks fail, the
Map-Reply MUST be discarded. Also, if the EID-prefixes claimed by
the ETR in the Map-Reply are not equal or less specific than the
EID-prefix authorization data inserted by the Map-Server, the ITR
MUST discard the Map-Reply.LISP-SEC metadata associated with a Map-Request is transported within
the Encapsulated Control Message that contains the Map-Request.LISP-SEC metadata associated with the Map-Reply is transported within
the Map-Reply itself.LISP-SEC uses the ECM (Encapsulated Control Message) defined in
with Type set to 8, and S bit set
to 1 to indicate that the LISP header includes Authentication Data
(AD). The format of the LISP-SEC ECM Authentication Data is defined in
the following figure. OTK-AD stands for One-Time Key Authentication
Data and EID-AD stands for EID Authentication Data.AD Type: 1 (LISP-SEC Authentication Data)V: Key Version bit. This bit is toggled when the sender
switches to a new OTK wrapping keyReserved: Set to 0 on transmission and ignored on receipt.Requested HMAC ID: The HMAC algorithm requested by the ITR. See
for details.OTK Length: The length (in bytes) of the OTK Authentication
Data (OTK-AD), that contains the OTK Preamble and the OTK.OTK Encryption ID: The identifier of the key wrapping algorithm
used to encrypt the One-Time-Key. When a 128-bit OTK is sent
unencrypted by the Map-Resolver, the OTK Encryption ID is set to
NULL_KEY_WRAP_128. See for more
details.One-Time-Key Preamble: set to 0 if the OTK is not encrypted.
When the OTK is encrypted, this field may carry additional
metadata resulting from the key wrapping operation. When a 128-bit
OTK is sent unencrypted by Map-Resolver, the OTK Preamble is set
to 0x0000000000000000 (64 bits). See for details.One-Time-Key: the OTK encrypted (or not) as specified by OTK
Encryption ID. See for
details.EID-AD Length: length (in bytes) of the EID Authentication Data
(EID-AD). The ITR MUST set EID-AD Length to 4 bytes, as it only
fills the KDF ID field, and all the remaining fields part of the
EID-AD are not present. An EID-AD MAY contain multiple
EID-records. Each EID-record is 4-byte long plus the length of the
AFI-encoded EID-prefix.KDF ID: Identifier of the Key Derivation Function used to
derive the MS-OTK. The ITR SHOULD use this field to indicate the
recommended KDF algorithm, according to local policy. The
Map-Server can overwrite the KDF ID if it does not support the KDF
ID recommended by the ITR. See Section 5.4 for more details.Record Count: The number of records in this Map-Request
message. A record is comprised of the portion of the packet that
is labeled 'Rec' above and occurs the number of times equal to
Record Count.Reserved: Set to 0 on transmission and ignored on receipt.EID HMAC ID: Identifier of the HMAC algorithm used to protect
the integrity of the EID-AD. This field is filled by Map-Server
that computed the EID-prefix HMAC. See Section 5.4 for more
details.EID mask-len: Mask length for EID-prefix.EID-AFI: Address family of EID-prefix according to EID-prefix: The Map-Server uses this field to specify the
EID-prefix that the destination ETR is authoritative for, and is
the longest match for the requested EID.EID HMAC: HMAC of the EID-AD computed and inserted by
Map-Server. Before computing the HMAC operation the EID HMAC field
MUST be set to 0. The HMAC covers the entire EID-AD.LISP-SEC uses the Map-Reply defined in , with Type set to 2, and S bit set to 1
to indicate that the Map-Reply message includes Authentication Data
(AD). The format of the LISP-SEC Map-Reply Authentication Data is
defined in the following figure. PKT-AD is the Packet Authentication
Data that covers the Map-Reply payload.AD Type: 1 (LISP-SEC Authentication Data)EID-AD Length: length (in bytes) of the EID-AD. An EID-AD MAY
contain multiple EID-records. Each EID-record is 4-byte long plus
the length of the AFI-encoded EID-prefix.KDF ID: Identifier of the Key Derivation Function used to
derive MS-OTK. See for more
details.Record Count: The number of records in this Map-Reply message.
A record is comprised of the portion of the packet that is labeled
'Rec' above and occurs the number of times equal to Record
Count.Reserved: Set to 0 on transmission and ignored on receipt.EID HMAC ID: Identifier of the HMAC algorithm used to protect
the integrity of the EID-AD. See
for more details.EID mask-len: Mask length for EID-prefix.EID-AFI: Address family of EID-prefix according to .EID-prefix: This field contains an EID-prefix that the
destination ETR is authoritative for, and is the longest match for
the requested EID.EID HMAC: HMAC of the EID-AD, as computed by the Map-Server.
Before computing the HMAC operation the EID HMAC field MUST be set
to 0. The HMAC covers the entire EID-AD.PKT-AD Length: length (in bytes) of the Packet Authentication
Data (PKT-AD).PKT HMAC ID: Identifier of the HMAC algorithm used to protect
the integrity of the Map-reply Location Data.PKT HMAC: HMAC of the whole Map-Reply packet, including the
LISP-SEC Authentication Data. The scope of the authentication goes
from the Map-Reply Type field to the PKT HMAC field included.
Before computing the HMAC operation the PKT HMAC field MUST be set
to 0. See for more details.Upon creating a Map-Request, the ITR generates a random ITR-OTK
that is stored locally, together with the nonce generated as specified
in .The Map-Request MUST be encapsulated in an ECM, with the S-bit set
to 1, to indicate the presence of Authentication Data. If the ITR and
the Map-Resolver are configured with a shared key, the ITR-OTK
confidentiality SHOULD be protected by wrapping the ITR-OTK with the
algorithm specified by the OTK Encryption ID field. See for further details on OTK encryption.The Requested HMAC ID field contains the suggested HMAC algorithm
to be used by the Map-Server and the ETR to protect the integrity of
the ECM Authentication data and of the Map-Reply.The KDF ID field, specifies the suggested key derivation function
to be used by the Map-Server to derive the MS-OTK.The EID-AD length is set to 4 bytes, since the Authentication Data
does not contain EID-prefix Authentication Data, and the EID-AD
contains only the KDF ID field.In response to an encapsulated Map-Request that has the S-bit set,
an ITR MUST receive a Map-Reply with the S-bit set, that includes an
EID-AD and a PKT-AD. If the Map-Reply does not include both ADs, the
ITR MUST discard it. In response to an encapsulated Map-Request with
S-bit set to 0, the ITR expects a Map-Reply with S-bit set to 0, and
the ITR SHOULD discard the Map-Reply if the S-bit is set.Upon receiving a Map-Reply, the ITR must verify the integrity of
both the EID-AD and the PKT-AD, and MUST discard the Map-Reply if one
of the integrity checks fails.The integrity of the EID-AD is verified using the locally stored
ITR-OTK to re-compute the HMAC of the EID-AD using the algorithm
specified in the EID HMAC ID field. If the EID HMAC ID field does not
match the Requested HMAC ID the ITR SHOULD discard the Map-Reply and
send, at the first opportunity it needs to, a new Map-Request with a
different Requested HMAC ID field, according to ITR's local policy.
The ITR MUST set the EID HMAC ID field to 0 before computing the
HMAC.To verify the integrity of the PKT-AD, first the MS-OTK is derived
from the locally stored ITR-OTK using the algorithm specified in the
KDF ID field. This is because the PKT-AD is generated by the ETR using
the MS-OTK. If the KDF ID in the Map-Reply does not match the KDF ID
requested in the Map-Request, the ITR SHOULD discard the Map-Reply and
send, at the first opportunity it needs to, a new Map-Request with a
different KDF ID, according to ITR's local policy. The derived MS-OTK
is then used to re-compute the HMAC of the PKT-AD using the Algorithm
specified in the PKT HMAC ID field. If the PKT HMAC ID field does not
match the Requested HMAC ID the ITR SHOULD discard the Map-Reply and
send, at the first opportunity it needs to, a new Map-Request with a
different Requested HMAC ID according to ITR's local policy.Each individual Map-Reply EID-record is considered valid only if:
(1) both EID-AD and PKT-AD are valid, and (2) the intersection of the
EID-prefix in the Map-Reply EID-record with one of the EID-prefixes
contained in the EID-AD is not empty. After identifying the Map-Reply
record as valid, the ITR sets the EID-prefix in the Map-Reply record
to the value of the intersection set computed before, and adds the
Map-Reply EID-record to its EID-to-RLOC cache, as described in . An example of Map-Reply record
validation is provided in .The ITR SHOULD send SMR triggered Map Requests over the mapping
system in order to receive a secure Map-Reply. If an ITR accepts
piggybacked Map-Replies, it SHOULD also send a Map-Request over the
mapping system in order to securely verify the piggybacked
Map-Reply.The payload of a Map-Reply may contain multiple EID-records. The
whole Map-Reply is signed by the ETR, with the PKT HMAC, to provide
integrity protection and origin authentication to the EID-prefix
records claimed by the ETR. The Authentication Data field of a
Map-Reply may contain multiple EID-records in the EID-AD. The EID-AD
is signed by the Map-Server, with the EID HMAC, to provide integrity
protection and origin authentication to the EID-prefix records
inserted by the Map-Server.Upon receiving a Map-Reply with the S-bit set, the ITR first
checks the validity of both the EID HMAC and of the PKT-AD HMAC. If
either one of the HMACs is not valid, a log message is issued and
the Map-Reply is not processed any further. If both HMACs are valid,
the ITR proceeds with validating each individual EID-record claimed
by the ETR by computing the intersection of each one of the
EID-prefix contained in the payload of the Map-Reply with each one
of the EID-prefixes contained in the EID-AD. An EID-record is valid
only if at least one of the intersections is not the empty set.For instance, the Map-Reply payload contains 3 mapping record
EID-prefixes:1.1.1.0/241.1.2.0/241.2.0.0/16The EID-AD contains two EID-prefixes: 1.1.2.0/241.2.3.0/24The EID-record with EID-prefix 1.1.1.0/24 is not processed
since it is not included in any of the EID-ADs signed by the
Map-Server. A log message is issued.The EID-record with EID-prefix 1.1.2.0/24 is stored in the
map-cache because it matches the second EID-prefix contained in the
EID-AD.The EID-record with EID-prefix 1.2.0.0/16 is not processed since
it is not included in any of the EID-ADs signed by the Map-Server. A
log message is issued. In this last example the ETR is trying to
over claim the EID-prefix 1.2.0.0/16, but the Map-Server authorized
only 1.2.3.0/24, hence the EID-record is discarded.The processing performed by a PITR is equivalent to the
processing of an ITR. However, if the PITR is directly connected to
the ALT, the PITR performs the functions of both the ITR and the
Map-Resolver forwarding the Map-Request encapsulated in an ECM
header that includes the Authentication Data fields as described in
.MS-OTK confidentiality is required in the path between the
Map-Server and the ETR, the MS-OTK SHOULD be encrypted using the
preconfigured key shared between the Map-Server and the ETR for the
purpose of securing ETR registration . Similarly, if ITR-OTK
confidentiality is required in the path between the ITR and the
Map-Resolver, the ITR-OTK SHOULD be encrypted with a key shared
between the ITR and the Map-Resolver.The OTK is encrypted using the algorithm specified in the OTK
Encryption ID field. When the AES Key Wrap algorithm is used to
encrypt a 128-bit OTK, according to [RFC3339], the AES Key Wrap
Initialization Value MUST be set to 0xA6A6A6A6A6A6A6A6 (64 bits). The
output of the AES Key Wrap operation is 192-bit long. The most
significant 64-bit are copied in the One-Time Key Preamble field,
while the 128 less significant bits are copied in the One-Time Key
field of the LISP-SEC Authentication Data.When decrypting an encrypted OTK the receiver MUST verify that the
Initialization Value resulting from the AES Key Wrap decryption
operation is equal to 0xA6A6A6A6A6A6A6A6. If this verification fails
the receiver MUST discard the entire message.When a 128-bit OTK is sent unencrypted the OTK Encryption ID is set
to NULL_KEY_WRAP_128, and the OTK Preamble is set to
0x0000000000000000 (64 bits).Upon receiving an encapsulated Map-Request with the S-bit set, the
Map-Resolver decapsulates the ECM message. The ITR-OTK, if encrypted,
is decrypted as specified in .The Map-Resolver, as specified in , originates a new ECM header with
the S-bit set, that contains the unencrypted ITR-OTK, as specified in
, and the other data derived from the
ECM Authentication Data of the received encapsulated Map-Request.The Map-Resolver then forwards the received Map-Request,
encapsulated in the new ECM header that includes the newly computed
Authentication Data fields.Upon receiving an ECM encapsulated Map-Request with the S-bit set,
the Map-Server process the Map-Request according to the value of the
S-bit contained in the Map-Register sent by the ETR during
registration.If the S-bit contained in the Map-Register was clear the Map-Server
decapsulates the ECM and generates a new ECM encapsulated Map-Request
that does not contain an ECM Authentication Data, as specified in
. The Map-Server does not perform
any further LISP-SEC processing.If the S-bit contained in the Map-Register was set the Map-Server
decapsulates the ECM and generates a new ECM Authentication Data. The
Authentication Data includes the OTK-AD and the EID-AD, that contains
EID-prefix authorization information, that are ultimately sent to the
requesting ITR.The Map-Server updates the OTK-AD by deriving a new OTK (MS-OTK)
from the ITR-OTK received with the Map-Request. MS-OTK is derived
applying the key derivation function specified in the KDF ID field. If
the algorithm specified in the KDF ID field is not supported, the
Map-Server uses a different algorithm to derive the key and updates
the KDF ID field accordingly.The Map-Server and the ETR MUST be configured with a shared key for
mapping registration according to . If MS-OTK confidentiality is
required, then the MS-OTK SHOULD be encrypted, by wrapping the MS-OTK
with the algorithm specified by the OTK Encryption ID field as
specified in .The Map-Server includes in the EID-AD the longest match registered
EID-prefix for the destination EID, and an HMAC of this EID-prefix.
The HMAC is keyed with the ITR-OTK contained in the received ECM
Authentication Data, and the HMAC algorithm is chosen according to the
Requested HMAC ID field. If The Map-Server does not support this
algorithm, the Map-Server uses a different algorithm and specifies it
in the EID HMAC ID field. The scope of the HMAC operation covers the
entire EID-AD, from the EID-AD Length field to the EID HMAC field,
which must be set to 0 before the computation.The Map-Server then forwards the updated ECM encapsulated
Map-Request, that contains the OTK-AD, the EID-AD, and the received
Map-Request to an authoritative ETR as specified in .If the Map-Server is in proxy mode, it generates a Map-Reply, as
specified in , with the S-bit
set to 1. The Map-Reply includes the Authentication Data that
contains the EID-AD, computed as specified in , as well as the PKT-AD computed as
specified in .Upon receiving an encapsulated Map-Request with the S-bit set, the
ETR decapsulates the ECM message. The OTK field, if encrypted, is
decrypted as specified in to obtain
the unencrypted MS-OTK.The ETR then generates a Map-Reply as specified in and includes an Authentication Data
that contains the EID-AD, as received in the encapsulated Map-Request,
as well as the PKT-AD.The EID-AD is copied from the Authentication Data of the received
encapsulated Map-Request.The PKT-AD contains the HMAC of the whole Map-Reply packet, keyed
with the MS-OTK and computed using the HMAC algorithm specified in the
Requested HMAC ID field of the received encapsulated Map-Request. If
the ETR does not support the Requested HMAC ID, it uses a different
algorithm and updates the PKT HMAC ID field accordingly. The scope of
the HMAC operation covers the entire PKT-AD, from the Map-Reply Type
field to the PKT HMAC field, which must be set to 0 before the
computation.Finally the ETR sends the Map-Reply to the requesting ITR as
specified in .The LISP-SEC threat model described in , assumes that the LISP Mapping System is
working properly and eventually delivers Map-Request messages to a
Map-Server that is authoritative for the requested EID.Security is not yet embedded in LISP+ALT but BGP route filtering
SHOULD be deployed in the ALT infrastructure to enforce proper routing
in the mapping system. The SIDR working group is currently addressing
prefix and route advertisement authorization and authentication for
BGP. While following SIDR recommendations in the global Internet will
take time, applying these recommendations to the ALT, which relies on
BGP, should be less complex, as ALT is currently small and with a
limited number of operators. Ultimately, deploying the SIDR
recommendations in ALT further ensures that the fore mentioned
assumption is true.It is also assumed that no man-in-the-middle attack can be carried
out against the ALT router to ALT router tunnels, and that the
information included into the Map-Requests, in particular the OTK,
cannot be read by third-party entities. It should be noted that the
integrity of the Map-Request in the ALT is protected by BGP
authentication, and that in order to provide OTK confidentiality in
the ALT mapping system the ALT router to ALT router tunnels MAY be
deployed using IPsec (ESP).Map-Register security, including the right for a LISP entity to
register an EID-prefix or to claim presence at an RLOC, is out of the
scope of LISP-SEC.The ITR-OTK MUST be generated by a properly seeded pseudo-random
(or strong random) source. See for
advice on generating security-sensitive random dataIf the Map-Server and the ETR are colocated, LISP-SEC does not
provide protection from overclaiming attacks mounted by the ETR.
However, in this particular case, since the ETR is within the trust
boundaries of the Map-Server, ETR's overclaiming attacks are not
included in the threat model.The following HMAC ID values are defined by this memo for use as
Requested HMAC ID, EID HMAC ID, and PKT HMAC ID in the LISP-SEC
Authentication Data:AUTH-HMAC-SHA-1-96 MUST be supported, AUTH-HMAC-SHA-256-128 should
be supported.The following OTK Encryption ID values are defined by this memo for
use as OTK key wrap algorithms ID in the LISP-SEC Authentication
Data:NULL-KEY-WRAP-128, and AES-KEY-WRAP-128 MUST be supported.NULL-KEY-WRAP-128 is used to carry an unencrypted 128-bit OTK, with
a 64-bit preamble set to 0x0000000000000000 (64 bits).The following KDF ID values are defined by this memo for use as KDF
ID in the LISP-SEC Authentication Data:HKDF-SHA1-128 MUST be supportedThe authors would like to acknowledge Pere Monclus, Dave Meyer, Dino
Farinacci, Brian Weis, David McGrew, Darrel Lewis and Landon Curt Noll
for their valuable suggestions provided during the preparation of this
document.