PANA Working Group Internet Draft M. Parthasarathy Category: Informational Tahoe Networks Document: draft-ietf-pana-threats-eval-04.txt May 2003 Expires: November 2003 PANA Threat Analysis and Security Requirements Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 except that the right to produce derivative works is not granted. 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. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract The PANA (Protocol for carrying authentication for Network Access) working group is developing methods for authenticating clients to the access network using IP based protocols. This document discusses the threats to such protocols. The security requirements arising out of these threats will be used as additional input to the PANA WG for designing the IP based network access authentication protocol. Parthasarathy Expires November 2003 [Page 1]
PANA threat analysis May 2003 Table of Contents 1.0 Introduction..................................................2 2.0 Keywords......................................................2 3.0 Terminology and Definitions...................................3 4.0 Usage Scenarios...............................................4 5.0 Trust Relationships...........................................4 6.0 Threat Scenarios..............................................5 6.1 PAA Discovery..............................................6 6.2 Authentication.............................................7 6.3 PaC leaving the network...................................10 6.4 Service theft.............................................11 6.5 PAA-EP communication......................................11 6.6 Miscellaneous attacks.....................................12 7.0 Summary of Requirements......................................13 8.0 Security Considerations......................................14 9.0 Normative References.........................................14 10.0 Informative References......................................14 11.0 Acknowledgments.............................................15 12.0 Revision Log................................................15 13.0 Author's Address............................................16 14.0 Full Copyright Statement....................................16 1.0 Introduction The PANA (Protocol for carrying authentication for Network Access) working group is developing methods for authenticating clients to the access network using IP based protocols. This document discusses the threats to such IP based protocols. A client wishing to get access to the network must carry on multiple steps. First, it needs to discover the IP address of the PANA authentication agent (PAA) and then execute an authentication protocol to authenticate itself to the network. Once the client is authenticated, there might be other messages exchanged during the lifetime of the network access. This document discusses the threats in these steps without discussing any solutions. The requirements arising out of these threats will be used as input to the PANA working group. 2.0 Keywords 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 [KEYWORDS]. Parthasarathy Expires November 2003 [Page 2]
PANA threat analysis May 2003 3.0 Terminology and Definitions Client Access Device A network element (e.g., notebook computer, PDA, etc.) that requires access to a provider's network. Network Access Server (NAS) Network device that provides access to the network. PANA Client (PaC) An entity in the edge subnet, who is wishing to obtain network access from a PANA authentication agent within a network. A PANA client is associated with a device and a set of credentials to prove its identity within the scope of PANA. PANA Authentication Agent (PAA) An entity whose responsibility is to authenticate the PANA client and grant network access service to the client's device. Authentication Server (AS) An entity that authenticates the PANA client. It may be co-located with PANA authentication agent or part of the back-end infrastructure. Device Identifier (DI) The identifier used by the network as a handle to control and police the network access of a client. Depending on the access technology, identifier might contain any of IP address, link-layer address, switch port number, etc. of a device. PANA authentication agent keeps a table for binding device identifiers to the PANA clients. At most one PANA client should be associated with a DI on a PANA authentication agent. Enforcement Point (EP) A node that is capable of filtering packets sent by the PANA client using the DI information authorized by PANA authentication agent. Compound methods Parthasarathy Expires November 2003 [Page 3]
PANA threat analysis May 2003 Authentication protocol where, sequence of methods are used one after an other or where methods are tunneled inside an another independently established tunnel between the client and server [TUN-EAP]. 4.0 Usage Scenarios PANA is intended to be used in an environment where there is no a priori trust relationship or security association between the PaC and other nodes like PAA and EP. In these environments, one may observe the following. o The link between PaC and PAA may be a shared medium (e.g., Ethernet) or may not be a shared medium (e.g., DSL network). o All the PaCs may be authenticated to the access network at layer 2 (e.g., 3GPP2 CDMA network) and share a security association with layer 2 authentication agent (e.g., 802.11 [IEEE-802.11] Access point), but still do not trust each other. The scenarios mentioned above affect the threat model of PANA. This document discusses the various threats in the context of the above network access scenarios for a better understanding of the threats. In the following discussion, any reference to link that is not shared (or non-shared) is assumed to be physically secure. If such an assumption cannot be made about the link, then it becomes the same as the link that is being shared by more than one node. 5.0 Trust Relationships PANA authentication involves a client (PaC), PANA agent (PAA), Authentication server (AS) and an Enforcement point (EP). The entities that have a priori trust relationships before PANA begins are as follows. 1) PAA and AS: PaC belonging to the same administrative domain as the AS, often needs to use resources provided by PAA that belongs to another administrative domain. PAA authenticates the PaC before providing local network access. The credentials provided by PaC for authentication may or may not be understood by PAA. If PAA does not understand the credentials, it needs to communicate with the AS in a different domain to verify the credentials. The threats in the communication path between PAA and AS are already covered in [RAD-EAP]. To counter these threats, the communication between PAA and AS are secured using a static or dynamic security association. Parthasarathy Expires November 2003 [Page 4]
PANA threat analysis May 2003 2) PAA and EP: PAA and EP belong to the same administrative domain. Hence, the network operator can setup a security association to protect the traffic exchanged between them. This document discusses the threats in this path. 3) PaC and AS: PaC and AS belong to the same administrative domain and share a trust relationship. When PaC uses a different domain than its home for network access, it provides its credentials to the PAA in the visited network for authentication. The information provided by PaC traverses the PaC-PAA path and PAA-AS path. The threats in PAA-AS path are already discussed in [RAD-EAP]. This document discusses the threats in PaC-PAA path. It is possible that some of the entities like PAA, AS and EP are co-located. In those cases, it can be safely assumed that there are no significant external threats. The entities that do not have any trust relationship before PANA begins are as follows. 1) PaC and PAA: PaC and PAA normally belong to two different administrative domains. They do not necessarily share a trust relationship initially. They establish a security association in the process of authentication. All messages exchanged between PaC and PAA are subject to various threats, which are discussed in this document. 2) PaC and EP: EP belongs to the same administrative domain as PAA and hence PaC and EP do not necessarily share a trust relationship initially. When PaC is successfully authenticated, it may result in key establishment between PaC and PAA, which can be further used to secure the link between PaC and EP. For example, EAP keying framework [EAP-KEY], defines a three party EAP exchange where the clients derive the transient sessions keys to secure the link between the peer and NAS in their final step. Similarly, PANA will provide the ability to establish keys between PaC and EP that can be used to secure the link further. This is further discussed in section 6.4 below. 6.0 Threat Scenarios The PANA authentication client (PaC) needs to discover the PAA first. This involves either sending solicitations or waiting for advertisements. Once it has discovered the PAA, it will lead to authentication exchange with PAA. Once the access is granted, PaC will most likely exchange data with other nodes in the Internet. All of these are vulnerable to denial of service (DoS), man-in-the-middle (MITM) and service theft attacks. Parthasarathy Expires November 2003 [Page 5]
PANA threat analysis May 2003 The threats are grouped by the various stages the client goes through to gain access to the network. Section 6.1 discusses the threats related to PAA discovery. Section 6.2 discusses the threats related to authentication itself. Section 6.3 discusses the threats involved while leaving the network. Section 6.4 discusses service theft. Section 6.5 discusses the threats in PAA-EP path. Section 6.6 discusses the miscellaneous threats. Some of the threats discussed in the following sections may be specific to shared links. The threat may be absent on non-shared links. Hence, it is only required to prevent the threat on shared links. Instead of specifying a separate set of requirements for shared links and non-shared links, this document just specifies one set of requirements with the following wording: "PANA MUST be able to prevent threat X". This means that the PANA protocol should be capable of preventing threat X. The feature that prevents threat X may or may not be used depending on the deployment. 6.1 PAA Discovery PaC is in the process of discovering the PAA. The PAA is discovered by sending solicitations or receiving advertisements. Following are the possible threats. T6.1.1: A malicious node can pretend to be a PAA by sending a spoofed advertisement. In existing dial-up networks, the clients authenticate to the network but generally do not verify the authenticity of the messages coming from Network Access Server (NAS). This mostly works because the link between the device and the NAS is not shared with other nodes (assuming that nobody tampers with the physical link), and clients trust the NAS and the phone network to provide the service. Spoofing attacks are not present in this environment because the PaC may assume that the other end of the link is the PAA. In environments where the link is shared, this threat is present as any node can pretend to be a PAA. Even if the nodes are authenticated at layer 2, this threat is present. It is difficult to protect the discovery process, as there is no a priori trust relationship between PAA and PaC. It might be possible for the EP to filter out the packets coming from PaC that resembles PAA packets and hence this threat can be prevented in such environments. The advertisement may be used to include other information like supported authentication methods etc., besides the discovery of the PAA itself. This can lead to a bidding down attack, as a malicious node can send a spoofed advertisement with capabilities that indicate Parthasarathy Expires November 2003 [Page 6]
PANA threat analysis May 2003 less secure authentication methods than what the real PAA supports, thereby fooling the PaC into negotiating a less secure authentication method than what would otherwise be available. This is best avoided by limiting the amount of security-critical information sent during the PAA discovery process. Requirement 1 PANA MUST not assume that the discovery process is protected. Since, it is difficult to protect the discovery process, the security- critical information exchanged during the discovery process SHOULD be limited. 6.2 Authentication This section discusses the threats specific to the authentication protocol. Section 6.2.1 discusses the possible threat associated with success/failure indications that are transmitted to PaC at the end of the authentication. Section 6.2.2 discusses the man-in-the-middle attack when compound methods are used. Section 6.2.3 discusses the replay attack and section 6.2.4 discusses about the device identifier attack. 6.2.1 Success or Failure Indications Some authentication protocols e.g., EAP, has a special message to indicate success or failure. An attacker can send false authentication success or failure message to the PaC. By sending false failure message, the attacker can prevent the client from accessing the network. By sending false success message, the attacker can prematurely end the authentication exchange effectively denying service for the PaC. If the link is not shared, then this threat is absent as ingress filtering can prevent the attacker from impersonating as the PAA. If the link is shared, it is easy to spoof these packets. If layer 2 provides per-packet encryption with pair-wise keys, it might make it hard for the attacker to guess the success or failure packet that the client would accept. Even if the node is already authenticated at layer 2, it can still pretend to be a PAA and spoof the success or failure. This attack is possible if the success or failure indication is not protected using a security association between PaC and PAA. In order to avoid this attack, PaC and PAA should mutually authenticate each other. In the process of mutually authenticating each other, they should be able to establish keys to protect the success or failure indications. It may not be possible to protect the success or failure Parthasarathy Expires November 2003 [Page 7]
PANA threat analysis May 2003 indication always as the keys may not be established prior to transmitting the success or failure packet. If the client is re- authenticating to the network, it can use the previously established security association to protect the success or failure indications. Similarly, all PANA messages that are exchanged during the authentication prior to key establishment may not be protected. Requirement 2 PANA MUST be able to mutually authenticate PaC and PAA. PANA MUST be able to establish keys between PaC and PAA to protect the PANA messages. 6.2.2 MITM attack A malicious node can claim to be PAA to the real PaC and claim to be PaC to the real PAA. This is a man in the middle (MITM) attack where the PaC is fooled to think that it is communicating with real PAA and the real PAA is fooled to think that it is communicating with real PaC. If the link is not shared, this threat is absent as ingress filtering can prevent the attacker from acting as man in the middle. If the link is shared, this threat is present. Even if the layer 2 provides per-packet protection, the attacker can act as man in the middle and launch this attack. An instance of MITM attack, when compound authentication methods are used is described in [TUN-EAP]. In these attacks, the server first authenticates to the client. As the client has not proven its identity yet, the server acts as the man-in-the-middle, tunneling the identity of the legitimate client to gain access to the network. The attack is possible because there is no verification that the same entities participated among the compound methods. It is not possible to do such verification if compound methods are used without being able to create cryptographic binding among them. This implies that PANA will be vulnerable to such attacks if compound methods are used without being able to cryptographically bind them. Note that the attack does not exist if the keys derived during the tunnel establishment are not used for authenticating the client e.g., tunnel keys are used for just protecting the identity of the client. Requirement 3 When compound authentication methods are used in PANA, the methods MUST be cryptographically bound. 6.2.3 Replay Attack Parthasarathy Expires November 2003 [Page 8]
PANA threat analysis May 2003 A malicious node can replay the messages that caused authentication failure or success at a later time to create false failures or success. The attacker can also potentially replay other messages of the PANA protocol to deny service to the PaC. If the link is not shared, this threat is absent as ingress filtering can prevent the attacker from impersonating as PAA and replay the packets. If the link is shared, this threat is present. If the packets are encrypted at layer 2 using pair-wise keys, it will make it hard for the attacker to learn the unencrypted (i.e., original) packet that needs to be replayed. Even if layer 2 provides replay protection, the attacker can still replay the PANA messages (layer 3) for denying service to the client. Requirement 4 PANA MUST be able to protect itself against replay attacks. 6.2.4 Device Identifier Attack When the client is successfully authenticated, PAA sends access control information to EP for granting access to the network. The access control information typically contains the device identifier of the PaC, which is obtained from the IP headers and MAC headers of the packets exchanged during the authentication process. The attacker can gain unauthorized access into the network using the following steps. . An attacker pretends to be a PAA and sends advertisements. PaC gets fooled and starts exchanging packets with the attacker. . The attacker modifies the IP source address on the packet, adjusts the UDP/TCP checksum and forwards the packet to the real PAA. It does the same on return packets also. . When the real PaC is successfully authenticated, the attacker gains access to the network as the packets contained the IP address (and potentially the MAC address also) of the attacker. If the link is not shared, this threat is absent, as the attacker cannot impersonate as PAA and intercept the packets from PaC. If the link is shared, this threat is present. If the layer 2 provides per-packet protection, it is not possible to change the MAC address and hence this threat may be absent in such cases if EP filters both on IP and MAC address. Requirement 5 Parthasarathy Expires November 2003 [Page 9]
PANA threat analysis May 2003 PANA MUST be able to protect the device identifier against spoofing when it is exchanged between the PaC and PAA. 6.3 PaC leaving the network When the PaC leaves the network, it can inform the PAA before disconnecting from the network so that the resources used by PaC can be accounted properly. PAA may also choose to revoke the access any time if it deems necessary. Following are the possible threats. T6.3.1: A malicious node can pretend to be a PAA and revoke the access to PaC. T6.3.2: A malicious node can pretend to be a real PaC and transmit a disconnect message. T6.3.3: PaC can leave the network without notifying the PAA or EP e.g., the Ethernet cable is unplugged, system crash. An attacker can pretend to be the PaC and start using the network. If the link is not shared, threats T6.3.1 and T6.3.2 are absent. Threat T6.3.3 may still be present. If there is no layer 2 indication or the layer 2 indication cannot be relied up on, then the threat T6.3.3 is still present on non-shared links. If the link is shared, all of the above threats are present as any node on the link can spoof the disconnect message. Even if the layer 2 has per-packet authentication, the attacker can pretend to be a PaC e.g. by spoofing the IP address, and disconnect from the network. Similarly, any node can pretend to be a PAA and revoke the access to the PaC. Hence, T6.3.1 and T6.3.2 are possible even on links where layer 2 is secured. Threat T6.3.3 can be prevented if layer 2 provides per-packet authentication. The attacker cannot subsume the PaC that left the network without knowing the keys that protect the packet at layer 2. In some link layers, e.g., 802.11 [IEEE-802.11], disassociate and de-authenticate messages are not protected (even with [IEEE- 802.11i]). In such link layers, protecting PANA messages may not be very useful as the attacker can attack using the link layer mechanisms rather than PANA. Requirement 6 PANA MUST be able to protect disconnect and revocation messages. PANA MUST NOT depend on PaC sending a disconnect message. Parthasarathy Expires November 2003 [Page 10]
PANA threat analysis May 2003 6.4 Service theft An attacker can gain unauthorized access into the network by stealing the service from another client. Once the PaC is successfully authenticated, EP will have filters in place to prevent unauthorized access into the network. The filters will be based on something that will be carried on every packet. For example, the filter could be based on IP and MAC address where the packets will be dropped unless the packets coming with certain IP address match the MAC address also. Following are the possible threats. T6.4.1: Attacker can spoof both the IP and MAC address of an authorized client to gain unauthorized access. Attacker can launch this attack easily by just sniffing the wire for IP and MAC address. This lets the attacker use the network without any authorization, getting a free service. If the link is not shared, this threat is absent as ingress filtering can prevent one node from impersonating as another node. If the link is shared, this threat is present. If layer 2 provides per-packet protection using pair-wise keys, it can prevent the attacker from gaining unauthorized access. PANA MUST be able to prevent service theft. In some cases e.g. non- shared links, it is sufficient to provide access control information like IP address, MAC address, etc., to EP, which in turn can prevent unauthorized users from gaining access to the network by policing the packets for matching addresses. In the case of shared links, this information is not sufficient to prevent service theft. PANA MUST be able to bootstrap a shared secret between the PaC and PAA which can be further used to setup a security association (e.g., IPsec) between PaC and EP to prevent service theft on shared links. Requirement 7 PANA MUST securely bind the authenticated session to the device identifier of the client, to prevent service theft. PANA MUST be able to bootstrap a shared secret between the PaC and PAA which can be further used to setup a security association between PaC and EP to provide cryptographic protection against service theft on shared links. 6.5 PAA-EP communication After a successful authentication, PAA needs to communicate the access control information of the PaC to EP so that PaC will be allowed to access the network. The information communicated would Parthasarathy Expires November 2003 [Page 11]
PANA threat analysis May 2003 contain at least the device identifier of the PaC. If strong security is needed, PAA will communicate a shared secret known only to PaC and PAA, for setting up a security association between PaC and EP. Following are the possible threats. T6.5.1: Attacker can eavesdrop to learn the information communicated between PAA and EP. The attacker can further use this information to spoof the real PaC and also setup an security association for gaining access to the network. This threat is absent, if the attacker cannot eavesdrop the link e.g., PAA and EP are communicating on a separate link from that of visiting PaCs. T6.5.2: Attacker can pretend to be PAA and send false information to EP for gaining access to the network. The attacker has to send its own device identifier and also a shared secret in the case of stronger security so that EP will let the attacker access the network. If the communication between PAA and EP is protected, these threats are absent. Requirement 8 The communication between PAA and EP MUST be protected against eavesdropping and spoofing attacks. 6.6 Miscellaneous attacks T6.5.1: There are various forms of DoS attacks that can be launched on the PAA or AS. A few are mentioned below. As it is hard to defend against some of the DoS attacks, the protocol should be designed carefully to mitigate or prevent such attacks. . Attacker can bombard the PAA with lots of authentication requests. If PAA and AS are not collocated, PAA may have to allocate resources to store some state about PaC locally before it receives the response from the backend AS. This can deplete memory resources on PAA. . The attacker can force the PAA or AS to make computationally intensive operations with minimal effort, that can deplete the CPU resources of the PAA or AS. T6.5.2: PaC acquires IP address before PANA authentication begins using methods like e.g., DHCP in IPv4 and auto-configuration in IPv6 [PANAREQ]. If IP addresses are assigned before authentication, it opens up the possibility of DoS attack where malicious nodes can deplete the IP addresses by assigning multiple IP addresses. If stateless auto-configuration [ADDRCONF] is used, the attacker can respond to duplicate address detection probes sent by any node on the Parthasarathy Expires November 2003 [Page 12]
PANA threat analysis May 2003 network effectively not allowing the node to configure a link local address. If stateful mechanism is used in IPv6 e.g., DHCPv6, then this attack is still possible. Address depletion attack is not specific to PANA, but a known attack in DHCP [DHCP-AUTH]. If PANA assumes that the client has an IP address already, it opens up the network to the DoS attack. Requirement 9 PANA SHOULD not assume that the PaC has acquired an IP address before PANA begins. 7.0 Summary of Requirements 1. PANA MUST not assume that the discovery process is protected. Since, it is difficult to protect the discovery process, the security-critical information exchanged during the discovery process SHOULD be limited. 2. PANA MUST be able to mutually authenticate PaC and PAA. PANA MUST be able to establish keys between PaC and PAA to protect the PANA messages. 3. When compound authentication methods are used in PANA, the methods MUST be cryptographically bound. 4. PANA MUST be able to protect itself against replay attacks. 5. PANA MUST be able to protect the device identifier against spoofing when it is exchanged between the PaC and PAA. 6. PANA MUST be able to protect disconnect and revocation messages. PANA MUST NOT depend on PaC sending a disconnect message. 7. PANA MUST securely bind the authenticated session to the device identifier of the client, to prevent service theft. PANA MUST be able to bootstrap a shared secret between the PaC and PAA which can be further used to setup a security association between PaC and EP to provide cryptographic protection against service theft on shared links. 8. The communication between PAA and EP MUST be protected against eavesdropping and spoofing attacks. 9. PANA SHOULD not assume that the PaC has acquired an IP address before PANA begins. Parthasarathy Expires November 2003 [Page 13]
PANA threat analysis May 2003 8.0 Security Considerations This document discusses various threats with IP based network access protocol. 9.0 Normative References [PANAUS] Y. Ohba et. al, "Problem Space and Usage Scenarios for PANA", draft-ietf-pana-usage-scenarios-03.txt [KEYWORDS] S. Bradner, "Key words for use in RFCS to indicate requirement levels", RFC 2119, March 1997. 10.0 Informative References [PANAREQ] A. Yegin et al., "Protocol for Carrying Authentication for Network Access (PANA) Requirements and Terminology", draft-ietf-pana- requirements-04.txt [RADIUS] C. Rigney et. al, "Remote Authentication Dial In User Service", RFC2865, June 2000. [EAP-KEY] B. Aboba et. al, "EAP keying framework", draft- aboba- pppext-key-problem-06.txt [ADDRCONF] S. Thomson et. al, "IPv6 Stateless Address Autoconfiguration", RFC2462, December 1998. [DHCP-AUTH] R. Droms, et. al "Authentication for DHCP messages", RFC3118, June 2001. [RAD-EAP] B. Aboba, et. al, "Radius support for Extensible authentication protocol", draft-aboba-radius-rfc2869bis-21.txt [TUN-EAP] J. Puthenkulam et. al, "The compound authentication binding problem", draft-puthenkulam-eap-binding-02.txt [IPSEC] S. Kent et. al, "Security architecture for the Internet Protocol", RFC 2401, November 1998. [IEEE-802.11i] Institute of Electrical and Electronics Engineers "Unapproved Draft Supplement to Standard for Telecommunications and Information Exchange Between systems - LAN/MAN Specific Requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Specification for Enhanced Security", IEEE Draft 802.11i (work in progress), 2003. Parthasarathy Expires November 2003 [Page 14]
PANA threat analysis May 2003 [IEEE-802.11] Institute of Electrical and Electronics Engineers, "Information Technology - Telecommunications and Information Exchange between Systems - Local and Metropolitan Area Network - Specific Requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE Standard 802.11, 1999. 11.0 Acknowledgments The author would like to thank the following people (in no specific order) for providing valuable comments: Alper Yegin, Basavaraj Patil, Pekka Nikander, Bernard Aboba, Francis Dupont, Michael Thomas, Yoshihiro Ohba, Gabriel Montenegro, Tschofenig Hannes, Bill Sommerfeld, N. Asokan, Pete McCan and Derek Atkins. 12.0 Revision Log Changes between 03 and 04 -Added a new requirement for the disconnect notification. -Trust relationship section was rewritten. -Device identifier attack requirements was rewritten. -Service theft requirement was rewritten. -Added a new section for PAA-EP threats. Changes between revision 02 and 03 -Changed Requirement 1 to include text about weak authentication suites. -Rearranged the order of definitions in terminology section. -Removed some confusing text with respect to IPsec from the Service theft section. Changes between revision 01 and 02 -Renamed the section "Assumptions" to "Trust relationships" and added more text to clarify the relationship between PaC and EP. -Added more text for threats in PAA AS path. -Merged the "Type of Attacks" section into "Threat Scenarios" -Removed the requirement on DoS attack. -Reworded most of the requirements. Changes between revision 00 and 01 -Removed unused terms from section 3.0. -Removed identity protection as a threat after feedback from Atlanta IETF55 meeting. -Renamed the section "Attacks on Normal Data communication" to "Service theft". Removed confidentiality as a requirement from that section. Parthasarathy Expires November 2003 [Page 15]
PANA threat analysis May 2003 -Added a new threat "Device Identifier attack". 13.0 Author's Address Mohan Parthasarathy Tahoe Networks 3052 Orchard Drive San Jose, CA 95134 Phone: 408-944-8220 Email: mohanp@tahoenetworks.com 14.0 Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Parthasarathy Expires November 2003 [Page 16]
