Routing Working Group M. Jethanandani Internet-Draft Ciena Corporation Intended status: Informational D. Zhang Expires: June 19, 2013 Huawei Technologies co., LTD. December 16, 2012 Analysis of RSVP-TE Security According to KARP Design Guide draft-mahesh-karp-rsvp-te-analysis-00.txt Abstract This document analyzes RSVP-TE according to guidelines set forth in section 4.2 of KARP Design Guidelines [RFC6518]. Status of this Memo This Internet-Draft is submitted in full conformance with the 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 http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on June 19, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Jethanandani & Zhang Expires June 19, 2013 [Page 1] Internet-Draft RSVP-TE Analysis December 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 2. Current Security State of RSVP-TE . . . . . . . . . . . . . . 5 3. Gap Analysis for RSVP-TE . . . . . . . . . . . . . . . . . . . 7 4. IANA Requirements . . . . . . . . . . . . . . . . . . . . . . 8 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1. Normative References . . . . . . . . . . . . . . . . . . . 10 6.2. Informative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Jethanandani & Zhang Expires June 19, 2013 [Page 2] Internet-Draft RSVP-TE Analysis December 2012 1. Introduction In March 2006, the Internet Architecture Board (IAB) described an attack on core routing infrastructure as an ideal attack that would inflict the greatest amount of damage, in their Report from the IAB workshop on Unwanted Traffic March 9-10, 2006 [RFC4948], and suggests steps to tighten the infrastructure against the attack. This document performs the initial analysis of the current state of RSVP-TE according to the requirements of KARP Design Guidelines [RFC6518]. This draft builds on several previous analysis efforts into routing security. The OPSEC working group put together Issues with existing Cryptographic Protection Methods for Routing Protocols [RFC6039] an analysis of cryptographic issues with routing protocols and Analysis of BGP, LDP, PCEP, and MSDP Issues According to KARP Design Guide [draft-ietf-karp-routing-tcp-analysis] which is a analysis of the four routing protocols. Section 2 looks at the current security state of RSVP-TE. Section 3 does a analysis of the gap between the existing and the optimal security state of the protocol and suggest some areas where we need to improve. 1.1. Abbreviations BGP - Border Gateway Protocol DoS - Denial of Service KARP - Key and Authentication for Routing Protocols KDF - Key Derivation Function KEK - Key Encrypting Key KMP - Key Management Protocol LDP - Label Distribution Protocol LSP - Label Switch Path MAC - Message Authentication Code MKT - Master Key Tuple MPLS - Multi Protocol Label Switching MSDP - Multicast Source Distribution Protocol Jethanandani & Zhang Expires June 19, 2013 [Page 3] Internet-Draft RSVP-TE Analysis December 2012 MD5 - Message Digest algorithm 5 PCEP - Path Computation Element Protocol RSVP - Resource reSerVation Protocol TCP - Transmission Control Protocol UDP - User Datagram Protocol Jethanandani & Zhang Expires June 19, 2013 [Page 4] Internet-Draft RSVP-TE Analysis December 2012 2. Current Security State of RSVP-TE This section looks at RSVP-TE and the underlying transport protocol and key mechanisms built for the protocol. RSVP-TE is an extension of the RSVP protocol for traffic engineering. It supports the reservation of resources across IP networks and is used for establishing Multi Protocol Label Switching (MPLS) Label Switch Paths (LSPs). RSVP-TE signaling is used to establish both intra- and inter-domain TE LSPs. It is RSVP Cryptographic Authentication [RFC2747] that describes the format and use of RSVP's INTEGRITY objects to provide hop-by-hop integrity and authentication of RSVP messages. RSVP-TE which uses some of the same formats therefore can make use of some of the same authentication mechanisms. The rest of the document will therefore focus on current state of security for RSVP. Currently, there is no security approach specified for RSVP-TE particularly. However, the security mechanisms for RSVP RSVP Cryptographic Authentication [RFC2747] can be taken advantage of to provide the security protection for the RSVP-TE message transportation. There is a requirement that RSVP-TE headers and payload be authenticated. There is no requirement that they be encrypted and that work is outside the scope of KARP WG. RSVP Cryptographic Authentication [RFC2747] outlines the use HMAC-MD5. When using HMAC- MD5, the length of the keyed digests is 128 bits. In these cases RSVP checksum can be disabled in lieu of message digest. RSVP uses 64 bit monotonically increasing sequence numbers to prevent against replay attacks. The sequence number space is large enough to guarantee that a sequence number will never reach its maximum and roll back within a reasonable long period. To address the issue of out-of-order message delivery, the solution allows administrators to specify a sequence number window corresponding to the worst case reordering behavior. Instead of requiring the sequence number of an incoming packet to be strictly larger than the ones previously received, a packet will be accepted if its sequence number is within the window. The solution provides three approaches to generate unique monotonically increasing sequence numbers across a failure or a restart. The solutions include: 1. Maintaining sequence numbers in stable memory 2. Introducing the data from a local time clock into the generation of sequence numbers after a restart Jethanandani & Zhang Expires June 19, 2013 [Page 5] Internet-Draft RSVP-TE Analysis December 2012 3. Introducing the timing information from a Network Recovered Clock into the generation of sequence numbers after a restart. In addition, a handshake is defined for a receiver to get the latest value of a sequence number. Therefore, this solution is effective in addressing the issues caused by the rollback of sequence numbers across a system restart or failure. However, when a router uses the approach to generating sequence numbers with the time information from NTP, an attacker may try to deceive the router to generate a sequence number which is less than the sequence numbers it used to have, by sending replayed or foiled NTP information. The protocol states that manual keying should be supported and states the need for a key management protocol to distribute keys. It even states that the Key Identifier be the hook between RSVP and the key management protocol. But it deliberately excludes defining a integrated key management protocol technique in the draft. However, it does define a key lifetime that should be recorded for all systems using values such as KeyStartValid and KeyEndValid. It even advises that the keys should be changed on a regular basis and that multiple keys should be used to transition from one key to another. RSVP does not explicitly mention Denial of Service (DoS) attacks and how to prevent against it. However, RSVP-TE does know the peers that it should be communicating with and can therefore accept packets from known hosts only. Jethanandani & Zhang Expires June 19, 2013 [Page 6] Internet-Draft RSVP-TE Analysis December 2012 3. Gap Analysis for RSVP-TE This section outlines the differences between the current state of RSVP-TE and the desired state as outlined in sections 4.1 and 4.2 of KARP Design Guidelines [RFC6518]. In RSVP Cryptographic Authentication [RFC2747], only the usage of MD5 to generate digests for RSVP-TE messages is mentioned. In order to fulfill the requirement of supporting strong algorithms, at least the support of SHA-2 needs to be provided. In addition, in RSVP Cryptographic Authentication [RFC2747], three approaches to generating unique monotonically increasing sequence numbers across a failure and restart are introduced, but no approach is mandated. However, as mentioned above, when using Network Recovered Clocks into the generation of sequence numbers, the capability of RSVP-TE in tolerating inter-connection replay attacks will largely rely on the security of network timing protocols. Therefore, in future this approach should not be recommended. Jethanandani & Zhang Expires June 19, 2013 [Page 7] Internet-Draft RSVP-TE Analysis December 2012 4. IANA Requirements None Jethanandani & Zhang Expires June 19, 2013 [Page 8] Internet-Draft RSVP-TE Analysis December 2012 5. Acknowledgements Jethanandani & Zhang Expires June 19, 2013 [Page 9] Internet-Draft RSVP-TE Analysis December 2012 6. References 6.1. Normative References [RFC2385] Heffernan, A., "Protection of BGP Sessions via the TCP MD5 Signature Option", RFC 2385, August 1998. [RFC5926] Lebovitz, G. and E. Rescorla, "Cryptographic Algorithms for the TCP Authentication Option (TCP-AO)", RFC 5926, June 2010. [RFC6518] Lebovitz, G. and M. Bhatia, "Keying and Authentication for Routing Protocols (KARP) Design Guidelines", RFC 6518, February 2012. 6.2. Informative References [I-D.ietf-karp-threats-reqs] Lebovitz, G. and M. Bhatia, "Keying and Authentication for Routing Protocols (KARP) Overview, Threats, and Requirements", draft-ietf-karp-threats-reqs-06 (work in progress), September 2012. [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- Hashing for Message Authentication", RFC 2104, February 1997. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2409] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)", RFC 2409, November 1998. [RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic Authentication", RFC 2747, January 2000. [RFC3547] Baugher, M., Weis, B., Hardjono, T., and H. Harney, "The Group Domain of Interpretation", RFC 3547, July 2003. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [RFC4948] Andersson, L., Davies, E., and L. Zhang, "Report from the IAB workshop on Unwanted Traffic March 9-10, 2006", RFC 4948, August 2007. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. Jethanandani & Zhang Expires June 19, 2013 [Page 10] Internet-Draft RSVP-TE Analysis December 2012 [RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., and C. Pignataro, "The Generalized TTL Security Mechanism (GTSM)", RFC 5082, October 2007. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, June 2010. [RFC5961] Ramaiah, A., Stewart, R., and M. Dalal, "Improving TCP's Robustness to Blind In-Window Attacks", RFC 5961, August 2010. [RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues with Existing Cryptographic Protection Methods for Routing Protocols", RFC 6039, October 2010. [draft-ietf-karp-routing-tcp-analysis] Jethanandani, MJ., "Analysis of BGP, LDP, PCEP, MSDP Issues According to KARP Design Guide", July 2012. Jethanandani & Zhang Expires June 19, 2013 [Page 11] Internet-Draft RSVP-TE Analysis December 2012 Authors' Addresses Mahesh Jethanandani Ciena Corporation 1741 Technology Drive San Jose, CA 95110 USA Phone: +1 (408) 436-3313 Email: mjethanandani@gmail.com Dacheng Zhang Huawei Technologies co., LTD. Beijing, China Phone: Fax: Email: zhangdacheng@huawei.com URI: Jethanandani & Zhang Expires June 19, 2013 [Page 12]