draft-ietf-ospf-security-extension-manual-keying-03.txt   draft-ietf-ospf-security-extension-manual-keying-04.txt 
OSPF Working Group M. Bhatia OSPF Working Group M. Bhatia
Internet-Draft Alcatel-Lucent Internet-Draft Alcatel-Lucent
Intended status: Standards Track S. Hartman Intended status: Standards Track S. Hartman
Expires: April 25, 2013 Painless Security Expires: August 26, 2013 Painless Security
D. Zhang D. Zhang
Huawei Technologies co., LTD. Huawei Technologies co., LTD.
A. Lindem A. Lindem
Ericsson Ericsson
October 22, 2012 February 22, 2013
Security Extension for OSPFv2 when using Manual Key Management Security Extension for OSPFv2 when using Manual Key Management
draft-ietf-ospf-security-extension-manual-keying-03 draft-ietf-ospf-security-extension-manual-keying-04
Abstract Abstract
The current OSPFv2 cryptographic authentication mechanism as defined The current OSPFv2 cryptographic authentication mechanism as defined
in the OSPF standards is vulnerable to both inter-session and intra- in the OSPF standards is vulnerable to both inter-session and intra-
session replay attacks when its uses manual keying. Additionally, session replay attacks when its uses manual keying. Additionally,
the existing cryptographic authentication schemes do not cover the IP the existing cryptographic authentication schemes do not cover the IP
header. This omission can be exploited to carry out various types of header. This omission can be exploited to carry out various types of
attacks. attacks.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 25, 2013. This Internet-Draft will expire on August 26, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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neighbor. Hello packets may be reflected to cause a neighbor to neighbor. Hello packets may be reflected to cause a neighbor to
appear to have one-way communication. Old Database descriptions may appear to have one-way communication. Old Database descriptions may
be reflected in cases where the per-packet sequence numbers are be reflected in cases where the per-packet sequence numbers are
sufficiently divergent in order to disrupt an adjacency sufficiently divergent in order to disrupt an adjacency
[I-D.ietf-karp-ospf-analysis]. This is referred to as the IP layer [I-D.ietf-karp-ospf-analysis]. This is referred to as the IP layer
issue in [I-D.ietf-karp-threats-reqs]. issue in [I-D.ietf-karp-threats-reqs].
[RFC2328] states that implementations MUST offer keyed MD5 [RFC2328] states that implementations MUST offer keyed MD5
authentication. It is likely that this will be deprecated in favor authentication. It is likely that this will be deprecated in favor
of the stronger algorithms described in [RFC5709] in future of the stronger algorithms described in [RFC5709] in future
deployments [I-D.ietf-opsec-igp-crypto-requirements]. deployments [RFC6094].
This draft proposes a simple change in the cryptographic This draft proposes a simple change in the cryptographic
authentication mechanism, as currently described in [RFC5709], to authentication mechanism, as currently described in [RFC5709], to
prevent such IP layer attacks. prevent such IP layer attacks.
1.1. Requirements Section 1.1. Requirements Section
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [RFC2119]. document are to be interpreted as described in RFC2119 [RFC2119].
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Figure 7 - Extended Sequence Number Packet Extensions Figure 7 - Extended Sequence Number Packet Extensions
4. OSPF Packet Key Selection 4. OSPF Packet Key Selection
This section describes how the proposed security solution selects This section describes how the proposed security solution selects
long-lived keys from key tables. [I-D.ietf-karp-crypto-key-table]. long-lived keys from key tables. [I-D.ietf-karp-crypto-key-table].
Generally, a key used for OSPFv2 packet authentication should satisfy Generally, a key used for OSPFv2 packet authentication should satisfy
the following requirements: the following requirements:
o The key time period as defined by NotBefore and NotAfter must o For packet transmission, the key validity interval as defined by
include the current time. SendLifeTimeStart and SendLifeTimeEnd must include the current
time.
o For packet reception, the key validity interval as defined by
AcceptLifeTimeStart and AcceptLifeTimeEnd must include the current
time.
o The key can be used for the desired security algorithm. o The key can be used for the desired security algorithm.
In the remainder of this section, additional requirements for keys In the remainder of this section, additional requirements for keys
are enumerated for different scenarios. are enumerated for different scenarios.
4.1. Key Selection for Unicast OSPF Packet Transmission 4.1. Key Selection for Unicast OSPF Packet Transmission
Assume that a router R1 tries to send a unicast OSPF packet from its Assume that a router R1 tries to send a unicast OSPF packet from its
interface I1 to the interface R2 of a remote router R2 using security interface I1 to the interface R2 of a remote router R2 using security
protocol P via interface I at time T. Firstly consider the protocol P via interface I at time T. First, consider the
circumstances where R1 and R2 are not connected with a virtual link. circumstances where R1 and R2 are not connected with a virtual link.
R1 then needs to select a long long-lived symmetric key from its key R1 then needs to select a long long-lived symmetric key from its key
table. Because the key should be shared by the by both R1 and R2 to table. Because the key should be shared by the by both R1 and R2 to
protect the communication between I1 and I2, the key should satisfy protect the communication between I1 and I2, the key should satisfy
the following requirements: the following requirements:
o The Peer field includes the router ID of R2. o The Peers field is unused. OSPF authentiction is interface based.
o the PeerKeyID field is not "unknown". o The Interfaces field includes the local IP address of the
interface for nummbered interfaces or the MIB-II [RFC1213],
ifIndex for unnumbered interfaces.
o The Interfaces field includes I1. o The Direction field is either "out" or "both".
o the Direction field is either "out" or "both". When R1 and R2 are connected to a virtual link, the interfaces field
must identify the virtual endpoint rather than the virtual link.
Since there may be virtual links to the same router, the transit area
ID must be part of the identifier. Hence, the key should satisfy the
following requirements:
When R1 and R2 are connected to a virtual link, the third condition o The Peers field is unused. OSPF authentiction is interface based.
is a little more complex. Because the virtual link can be regarded
as an unnumbered point-to-point network, the IP address of the o The Interfaces field includes both the virtual endpoint's OSPF
interface actually used to send the packet (i.e., I1) is discovered router ID and the the transit area ID for the virtual link.
during routing table calculation. Therefore, when the system
operator configures keys to protect the virtual link, I1 is unknown o The Direction field is either "out" or "both".
and can be any OSPF interface in the OSPF virtual link's transit
area. Therefore, the key should be identified solely by the local
and remote router IDs rather than by the interface on which the
packet is sent. The third requirement list above should be changed
to "the Interface field includes the router ID".
4.2. Key Selection for Multicast OSPF Packet Transmission 4.2. Key Selection for Multicast OSPF Packet Transmission
If a router R1 sends an OSPF packet from its interface I1 to a If a router R1 sends an OSPF packet from its interface I1 to a
multicast address (e.g., AllSPFRouters, AllDRouters), it needs to multicast address (e.g., AllSPFRouters, AllDRouters), it needs to
select a key according to the following requirements: select a key according to the following requirements:
o The Peer field includes the multicast address. o The Peers field is unused. OSPF authentication is interface
based.
o The PeerKeyID field is "group".
o The Interfaces field includes I1. o The Interfaces field includes the local IP address of the
interface for nummbered interfaces or the MIB-II [RFC1213],
ifIndex for unnumbered interfaces.
o The Direction field is either "out" or "both". o The Direction field is either "out" or "both".
4.3. Key Selection for OSPF Packet Reception 4.3. Key Selection for OSPF Packet Reception
When Cryptographic Authentication is employed, the ID of the When Cryptographic Authentication is used, the ID of the
authentication key is included in the authentication field of the authentication key is included in the authentication field of the
OSPF packet header. Using this key ID, it is relatively easy for a OSPF packet header. Using this key ID, it is relatively easy for a
receiver to locate the key. The simple requirements are: receiver to locate the key. The simple requirements are:
o The Peer field includes the router ID of the sender. o The interface on which the key was received is associated with the
key's interface.
o The PeerKeyID field includes the key ID obtained from the o The PeerKeyName field includes the key ID obtained from the
authentication field. authentication field. Since OSPF keys are symmetric, the
LocalKeyName and PeerKeyName for OSPF keys will be identical.
o The Direction field is either "in" or "both". o The Direction field is either "in" or "both".
5. Mechanism to secure the IP header 5. Mechanism to secure the IP header
This document updates the definition of Apad which is currently a This document updates the definition of Apad which is currently a
constant defined in [RFC5709] to the source address from the IP constant defined in [RFC5709] to the source address from the IP
header of the OSPFv2 protocol packet. The overall cryptographic header of the OSPFv2 protocol packet. The overall cryptographic
authentication process defined in [RFC5709] remains unchanged. To authentication process defined in [RFC5709] remains unchanged. To
reduce the potential for confusion, this section minimizes the reduce the potential for confusion, this section minimizes the
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7. IANA Considerations 7. IANA Considerations
This document requests a new code point from the "OSPF Shortest Path This document requests a new code point from the "OSPF Shortest Path
First (OSPF) Authentication Codes" registry: First (OSPF) Authentication Codes" registry:
o TBD - Cryptographic Authentication with Extended Sequence Numbers. o TBD - Cryptographic Authentication with Extended Sequence Numbers.
The value 3 is recommended. The value 3 is recommended.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-karp-crypto-key-table]
Housley, R., Polk, T., Hartman, S., and D. Zhang,
"Database of Long-Lived Symmetric Cryptographic Keys",
draft-ietf-karp-crypto-key-table-06 (work in progress),
February 2013.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M.,
Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic
Authentication", RFC 5709, October 2009. Authentication", RFC 5709, October 2009.
8.2. Informative References 8.2. Informative References
[I-D.ietf-karp-crypto-key-table]
Housley, R. and T. Polk, "Database of Long-Lived Symmetric
Cryptographic Keys", draft-ietf-karp-crypto-key-table-00
(work in progress), November 2010.
[I-D.ietf-karp-ospf-analysis] [I-D.ietf-karp-ospf-analysis]
Hartman, S. and D. Zhang, "Analysis of OSPF Security Hartman, S. and D. Zhang, "Analysis of OSPF Security
According to KARP Design Guide", According to KARP Design Guide",
draft-ietf-karp-ospf-analysis-00 (work in progress), draft-ietf-karp-ospf-analysis-06 (work in progress),
March 2011. May 2013.
[I-D.ietf-karp-threats-reqs] [I-D.ietf-karp-threats-reqs]
Lebovitz, G., Bhatia, M., and R. White, "The Threat Lebovitz, G., Bhatia, M., and B. Weis, "The Threat
Analysis and Requirements for Cryptographic Authentication Analysis and Requirements for Cryptographic Authentication
of Routing Protocols' Transports", of Routing Protocols' Transports",
draft-ietf-karp-threats-reqs-02 (work in progress), draft-ietf-karp-threats-reqs-07 (work in progress),
April 2011. December 2012.
[I-D.ietf-opsec-igp-crypto-requirements] [RFC1213] McCloghrie, K. and M. Rose, "Management Information Base
Bhatia, M. and V. Manral, "Summary of Cryptographic for Network Management of TCP/IP-based internets:MIB-II",
Authentication Algorithm Implementation Requirements for STD 17, RFC 1213, March 1991.
Routing Protocols",
draft-ietf-opsec-igp-crypto-requirements-04 (work in
progress), October 2010.
[RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model [RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model
(USM) for version 3 of the Simple Network Management (USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", STD 62, RFC 3414, December 2002. Protocol (SNMPv3)", STD 62, RFC 3414, December 2002.
[RFC4222] Choudhury, G., "Prioritized Treatment of Specific OSPF [RFC4222] Choudhury, G., "Prioritized Treatment of Specific OSPF
Version 2 Packets and Congestion Avoidance", BCP 112, Version 2 Packets and Congestion Avoidance", BCP 112,
RFC 4222, October 2005. RFC 4222, October 2005.
[RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues [RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues
with Existing Cryptographic Protection Methods for Routing with Existing Cryptographic Protection Methods for Routing
Protocols", RFC 6039, October 2010. Protocols", RFC 6039, October 2010.
[RFC6094] Bhatia, M. and V. Manral, "Summary of Cryptographic
Authentication Algorithm Implementation Requirements for
Routing Protocols", RFC 6094, February 2011.
Authors' Addresses Authors' Addresses
Manav Bhatia Manav Bhatia
Alcatel-Lucent Alcatel-Lucent
Bangalore, Bangalore,
India India
Phone: Phone:
Email: manav.bhatia@alcatel-lucent.com Email: manav.bhatia@alcatel-lucent.com
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