INTERNET DRAFT draft-jangir-replay-attack-protection-00.txt Mohanlal Jangir Samsung India Software Operations Expires 23 Dec 2004 23 June 2004 IPSec Replay Attack Protection in Multisender Environment Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. Abstract The IPsec Architecture [RFC2401] and IPsec transform RFCs [RFC2402, RFC2406] define certain mechanisms for protecting IP traffic. One of the mechanisms defined is replay attack protection. But this mechanism is not addressed in multisender environment where multiple senders are sending packets for same destination SA (This includes sharing of SA as well as multicast). This document reviews the issues in multisender environment and addresses solution for this by identifying the sending SA and having replay attack protection against each sending SA. The documents also summarizes the changes needed in AH, ESP, Key management protocols, which would enable IPSec to protect against replay attack protection in multisender environment for same destination SA. Table of Contents 1. Introduction ............................................ 2 2. Change in Key Management Protocol ....................... 2 3. Label Management ........................................ 2 3.1. Label Management in Multicasting ...................... 2 3.2. Label Management in SA sharing ........................ 3 4. Change in Authentication Header ......................... 3 Mohanlal Jangir Expires Dec 23, 2004 [Page 1] Internet-Draft IPSec Replay Attach Check in June 2004 Multisender Environment 5. Inbound Authentication Header processing ................ 3 6. Replay Attack Protection with ESP ....................... 3 7. Intellectual Property Statement ......................... 4 8. Full Copyright Statement ................................ 4 9. Author's Address .........................................4 1. Introduction Replay protection in multisender environment has been an open issue since the RFC 2401. This draft addresses this issue by assigning a unique two byte identity label to each outbound SA. This could be done by distributing a unique label during SA establishment. The requirements of this distribution protocol are as follows: a. The label should have local significance b. The label should be issued by inbound SA owner 2. Change in Key Management Protocol This draft defines following new payload type for SA labeling as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Next Payload ! RESERVED ! Payload Length ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! RESERVED2 ! SA Identification Label ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Next Payload for SA Identification Label exchange can be defined as 14 for test purpose. 3. Label Management Label management for two different scenarios e.g. multicasting and SA sharing is described in following sections. 3.1. Label Management in Multicasting Label management in multicasting SHOULD be performed by GC (Group Controller). Each outbound SA in that multicast group MUST be assigned a group local SA label. SPI for all the SAs in that group will be same, so that all members in that group can use same SA for traffic protection. Each host joining the group will be getting SA parameters and unique SA label. This draft does not address, label management in case of multiples GCs. Mohanlal Jangir Expires Dec 23, 2004 [Page 2] Internet-Draft IPSec Replay Attach Check in June 2004 Multisender Environment 3.2. Label Management in SA sharing * Each outbound SA at every host must be assigned a unique identity label by the host, SAs are targeted for. * Each host, while establishing an inbound SA, must assign a local unique label to negotiating hosts outbound SA. * In this case SA parameters (keys, SPI) will be controlled by the host which owns inbound SA. * This label assignment should be done using the payload defined above. * The label generation is governed by local policy. The label could be a monotonically increasing number or a random number depending on implementation. Labels should be marked as free (can be assigned to other SA), when corresponding peer outbound SA is deleted. 4. Change in Authentication Header 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Header | Payload Len |Sending SA Identification Label| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Security Parameters Index (SPI) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number Field | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Authentication Data (variable) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Sender Identification Label û The RESERVED bytes in current Authentication Header should be replaced by sender identification label negotiated/assigned during key management negotiation. A host not supporting replay attack for multisender environment MUST send this field as zero. 5. Inbound Authentication Header processing Each receiver should maintain separate replay attack window for each sender. The replay attack check MUST be performed only after authenticating the packet. A host not supporting replay attack check against multiple senders SHOULD ignore the SA identification label. 6. Replay Attack Protection with ESP Presently this draft does not address this issue. Hosts wishing to have protection in this case SHOULD use AH + ESP. Mohanlal Jangir Expires Dec 23, 2004 [Page 3] Internet-Draft IPSec Replay Attach Check in June 2004 Multisender Environment 7. Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 Secretariat. 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Funding for the RFC editor function is currently provided by the Internet Society. 9. Author's Address Mohanlal Jangir Samsung India Software Operations Bangalore, INDIA Ph: +919845043943 E mail: mohanlal@samsung.com Mohanlal Jangir Expires Dec 23, 2004 [Page 4]