1 / 10

Securing PIM-SM Link-Local Messages

Securing PIM-SM Link-Local Messages. J.W. Atwood Salekul Islam Concordia University draft-atwood-pim-sm-linklocal-01. Problem Statement. PIM-SM draft says Recommend AH Assume manual keying, but allow automatic If IPsec, MUST authenticate all Anti-replay SHOULD be enabled AH says

ozzie
Download Presentation

Securing PIM-SM Link-Local Messages

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Securing PIM-SM Link-Local Messages J.W. Atwood Salekul Islam Concordia University draft-atwood-pim-sm-linklocal-01

  2. Problem Statement • PIM-SM draft says • Recommend AH • Assume manual keying, but allow automatic • If IPsec, MUST authenticate all • Anti-replay SHOULD be enabled • AH says • SHOULD NOT offer anti-replay when manually keyed

  3. cont • IPsec says • Security Policy Database (SPD) cannot represent a creation policy for a multicast SA • Therefore, only manually-configured SAD entries are possible • Apparent conclusion • We should not activate anti-replay for PIM Link-local messages • Actual conclusion • We can, it’s just harder…

  4. Per-interface or per-sender? • PIM-SM says • Per-interface may be useful • IPsec says • No (longer) need to support per-interface • AH says • Use SPI + destination + source for SSM • Use SPI + destination for ASM

  5. Who talks to whom? • Link-local messages go from one router to all its peer routers • Since all routers use ALL_PIM_ROUTERS, it looks like an ASM group • In fact, this is a collection of SSM groups • Therefore • All the counsel against anti-replay for multi-sender multicast groups does not apply • Link-local SA SHOULD be established as an SSM group

  6. Choices • Declare that ALL_PIM_ROUTERS operates as an SSM group when IPsec is enabled • This may be hard, because ALL_PIM_ROUTERS is used for BSR communication • Define LINK_LOCAL_PIM_ROUTERS or SECURE_PIM_ROUTERS to be in the SSM address range • But, we will need to secure BSR communication as well

  7. Manual Key Configuration • Number of peers will be small • AH says • Anti-replay SHOULD NOT be provided if SAs are manually keyed • Choices • Override AH (RFC 4302) • Define a negotiation protocol to ensure key generation and SA refresh on counter overflow

  8. Counter Overflow • If Extended Sequence Number is specified, 264control packets can be sent • This may justify overriding the AH prohibition. • Otherwise, we are prepared to work on defining the necessary negotiation protocol

  9. Validation • This proposal was formally validated, as part of the Master’s Thesis of Salekul Islam, using PROMELA and the SPIN tool. • Salekul Islam and J. William Atwood, "Security Issues in PIM-SM Link-local Messages", Proceedings of IEEE LCN 2004, Tampa, FL, 2004 November 16--18, pp. 402--403.

  10. Contact Information • PPT/PDF of these slides are at www.cse.concordia.ca/~bill/internet-drafts/IETF66-LinkLocal-01.ppt or IETF66-LinkLocal-01.pdf • Email addresses • bill@cse.concordia.ca • salek_is@cse.concordia.ca

More Related