[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00

     Routing Area Working Group                                    R. Rahman
                                                                     D. Ward
     Internet Draft                                            Cisco Systems
     Intended status: BCP                                       October 2008
     Expires: April 2009
     
     
     
                     Use of IP Router Alert Considered Dangerous
                   draft-rahman-rtg-router-alert-dangerous-00.txt
     
     
     Status of this Memo
     
        By submitting this Internet-Draft, each author represents that
        any applicable patent or other IPR claims of which he or she is
        aware have been or will be disclosed, and any of which he or she
        becomes aware will be disclosed, in accordance with Section 6 of
        BCP 79.
     
        Internet-Drafts are working documents of the Internet Engineering
        Task Force (IETF), its areas, and its working groups.  Note that
        other groups may also distribute working documents as Internet-
        Drafts.
     
        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."
     
        The list of current Internet-Drafts can be accessed at
        http://www.ietf.org/ietf/1id-abstracts.txt
     
        The list of Internet-Draft Shadow Directories can be accessed at
        http://www.ietf.org/shadow.html
     
        This Internet-Draft will expire on April 17, 2009.
     
     Abstract
     
        This document provides guidelines to address security concerns which
        arise with the use of IP Router Alert option [RFC2113] and [RFC2711].
        RSVP,[RFC2205] and [RFC3209], and IGMP [RFC3376] are some of the
        protocols which make use of the IP Router Alert option. IP datagrams
        carrying the Router Alert option are usually examined in a router's
        "slow path" and an excess of such datagrams can cause performance
        degradation or packet drops in a router's "slow path".
     
     
     
     


     Rahman                  Expires April 17, 2009                 [Page 1]


     Internet-Draft draft-rahman-rtg-router-alert-dangerous-00.txt   October
     2008
     
     
     Table of Contents
     
     
        1. Introduction...................................................2
        2. Conventions used in this document..............................2
        3. Security Risk Of IP Router Alert Option........................2
        4. Guidelines For Use Of IP Router Alert Option...................3
        5. Security Considerations........................................3
        6. IANA Considerations............................................4
        7. Conclusions....................................................4
        8. Acknowledgments................................................4
        9. References.....................................................5
           9.1. Normative References......................................5
     
     1. Introduction
     
        The main purpose of this document is to describe the security risks
        associated with the use of IP Router Alert and to discourage new
        applications and protocols from using IP Router Alert.
     
     2. Conventions used in this document
     
        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 [1].
     
     3. Security Risk Of IP Router Alert Option
     
     
        IP datagrams carrying the Router Alert option are usually examined in
        a router's "slow path" and an excess of such datagrams can cause
        performance degradation or packet drops in a router's "slow path".
     
        [RFC4081] and [RFC2711] mention the security risks associated with
        the use of the IP Router Alert option: flooding a router with bogus
        IP datagrams which contain the IP Router Alert option would cause a
        performance degradation of the router's "slow path" and can also lead
        to packet drops in the "slow path".
     
        [RFC2711] mentions that limiting, by rate or some other means, the
        use of Router Alert option is a way of protecting against a potential
        attack. If rate limiting is used as a protection mechanism and the
        granularity of the rate limiting is coarse, an attack using packet
        types of one protocol could severely degrade the operation of other
        protocols using IP Router Alert option.
     
     
     
     <Rahman>                Expires April 17, 2009                 [Page 2]


     Internet-Draft draft-rahman-rtg-router-alert-dangerous-00.txt   October
     2008
     
     
     4. Guidelines For Use Of IP Router Alert Option
     
        To protect the "slow path" against DOS attacks, a router MUST have a
        means of limiting the number of Router Alert IP datagrams which go to
        the "slow path".
     
        If there are multiple protocols which make use of IP Router Alert
        option on a router, the limiting MUST be able to distinguish between
        the various protocols. E.g. if rate limiting is used, there MUST be
        different rate limit pools for the protocols so that an attack on one
        protocol will not affect the operation of another protocol.
     
        IP Router Alert packets MUST NOT be sent to the "slow path" unless
        there is at least one protocol enabled which uses the IP Router Alert
        option.
     
        A router SHOULD inspect Router Alert packets before sending them to
        the "slow path" so that if the protocol to which a packet belongs is
        not enabled on the router or on the incoming interface (physical or
        virtual), then the packet is dropped.
     
        Introducing new protocols/applications which make use of IP Router
        Alert option MUST not provide a means of attacking or harming
        deployed protocols such as RSVP and IGMP which already make use of
        the IP Router Alert option.
     
        Routing and signaling users of IP Router Alert, e.g. IGMP and RSVP,
        are the highest priority users and MUST NOT be impacted by other
        users of IP Router Alert.
     
        Any application that relies on IP Router Alert should expect that the
        incoming packets MAY be dropped by default and that a special filter
        is needed to let the packets through.
     
        All non-routing and non-signaling IP Router Alert packets, when
        enabled, may be significantly rate limited.
     
        Creating an application or protocol that uses IP Router Alert is
        considered harmful and is strongly discouraged. A different mechanism
        should be used to decrease the risk of impacting existing routing and
        signaling protocols which use IP Router Alert
     
     5. Security Considerations
     
        This document provides guidelines for security risks which are
        present with the use of IP Router Alert option.  Its purpose is to
     
     
     <Rahman>                Expires April 17, 2009                 [Page 3]


     Internet-Draft draft-rahman-rtg-router-alert-dangerous-00.txt   October
     2008
     
     
        have greater security against DDOS attacks and to discourage new
        applications from using IP Router Alert since this would cause a
        security risk against current users of IP Router Alert.
     
     
     6. IANA Considerations
     
     
     
     7. Conclusions
     
        Use of IP Router Alert is a security risk and should be discouraged
        for new applications and protocols.
     
     8. Acknowledgments
     
        This document was prepared using 2-Word-v2.0.template.dot.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     <Rahman>                Expires April 17, 2009                 [Page 4]


     Internet-Draft draft-rahman-rtg-router-alert-dangerous-00.txt   October
     2008
     
     
     9. References
     
         [RFC2113] "IP Router Alert Option", RFC 2113, D. Katz, February
           1997.
        [RFC2711] "IPv6 Router Alert Option", RFC 2711, C. Partridge, et al,
           October 1999.
        [RFC2205] "Resource ReSerVation Protocol (RSVP) - Version 1,
           Functional Specification", RFC 2205, Braden, et al, September
           1997.
        [RFC3209] "Extensions to RSVP for LSP Tunnels", D. Awduche, et al,
           RFC 3209, December 2001.
        [RFC3376] "Internet Group Management Protocol, Version 3", RFC 3376,
           B. Cain, et al, October 2002.
        [RFC4081] "Security Threats For Next Steps in Signaling (NSIS)", RFC
           4081, H. Tschofenig, et al, June 2005
     
     
     9.1. Normative References
     
        [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
              Levels", BCP 14, RFC 2119, March 1997.
     
        [2]   Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, Internet Mail Consortium and
              Demon Internet Ltd., November 1997.
     
        [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.
     
        [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
                  Syntax Specifications: ABNF", RFC 2234, Internet Mail
                  Consortium and Demon Internet Ltd., November 1997.
     
     Author's Addresses
     
        Reshad Rahman
        Cisco Systems Inc.
        2000 Innovation Dr.,
        Kanata, Ontario, K2K 3E8
        Canada.
        Phone: (613)-254-3519
        Email: rrahman@cisco.com
     
        David Ward
        Cisco Systems Inc.
        3750 Cisco Way,
     
     
     <Rahman>                Expires April 17, 2009                 [Page 5]


     Internet-Draft draft-rahman-rtg-router-alert-dangerous-00.txt   October
     2008
     
     
        San Jose, California, 95134
        United States
        Phone: (651)-726-2368
        Email: wardd@cisco.com
     
     
     Full Copyright Statement
     
        Copyright (C) The IETF Trust (2008).
     
        This document is subject to the rights, licenses and restrictions
        contained in BCP 78, and except as set forth therein, the authors
        retain all their rights.
     
        This document and the information contained herein are provided on an
        "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
        OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
        THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
        OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
        THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
        WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
     
     Intellectual Property Statement
     
        The IETF takes no position regarding the validity or scope of any
        Intellectual Property Rights or other rights that might be claimed to
        pertain to the implementation or use of the technology described in
        this document or the extent to which any license under such rights
        might or might not be available; nor does it represent that it has
        made any independent effort to identify any such rights.  Information
        on the procedures with respect to rights in RFC documents can be
        found in BCP 78 and BCP 79.
     
        Copies of IPR disclosures made to the IETF Secretariat and any
        assurances of licenses to be made available, or the result of an
        attempt made to obtain a general license or permission for the use of
        such proprietary rights by implementers or users of this
        specification can be obtained from the IETF on-line IPR repository at
        http://www.ietf.org/ipr.
     
        The IETF invites any interested party to bring to its attention any
        copyrights, patents or patent applications, or other proprietary
        rights that may cover technology that may be required to implement
        this standard.  Please address the information to the IETF at
        ietf-ipr@ietf.org.
     
     
     
     <Rahman>                Expires April 17, 2009                 [Page 6]
     

Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/