Networking Group H. Rafiee INTERNET-DRAFT Huawei Technologies Duesseldorf GmbH Intended status: Informational C. Meinel Hasso Plattner Institute Expires: March 9, 2015 September 9, 2014 Recommendations for Local Security Deployments Abstract There are currently some mechanisms available to mitigate attacks in local networks -- Secure Neighbor Discovery (SeND), First Hop Security (FHS), SAVI, etc.. The purpose of this document is to compare these mechanisms and offer some recommendations regarding the implementations and deployments of these mechanisms. 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. 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Code Components extracted from this document must Rafiee & Meinel Expires March 9, 2015 [Page 1] INTERNET DRAFT local security Deployment September 9, 2014 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. IPv6 First-Hop Security (FHS) . . . . . . . . . . . . . . . . 3 3. Local link Security for all nodes . . . . . . . . . . . . . . 4 3.1. Secure Neighbor Discovery . . . . . . . . . . . . . . . . 4 3.1.1. Identifying Obstacles for SeND Deployments . . . . . 4 3.1.1.1. CGA Performance and Complexity . . . . . . . . . 4 3.1.1.2. CGA Security Issue . . . . . . . . . . . . . . . 5 3.1.1.3. Router Authorization Problem . . . . . . . . . . 5 3.2. SAVI mechanisms . . . . . . . . . . . . . . . . . . . . . 5 4. Recommendations for Local Security Deployments . . . . . . . 5 4.1. Other Alternative Algorithms in place of CGA . . . . . . 6 4.2. Router Authorization and Preventing Layer 2 Spoofing . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative . . . . . . . . . . . . . . . . . . . . . . . . 6 7.2. Informative . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Rafiee & Meinel Expires March 9, 2015 [Page 2] INTERNET DRAFT local security Deployment September 9, 2014 1. Introduction Local security is a very important issue in everyday life, especially, in large enterprises that this trust can be broken by one of fired employees. There are currently some existing mechanisms that might be used to mitigate the attacks in local networks. The focus of this document is to explain these mechanisms and discuss about their level and costs of security they can provide for the nodes and offer some recommendations for their deployments. This document also focuses on the problems for Secure Neighbor Discovery (SeND) [RFC3971] deployments and offer some recommendations and new models to try to remove the obstacles for its deployments. 2. IPv6 First-Hop Security (FHS) One of the growing concerns in local security is that the attacker can forge the identity of the routers or play other attacks during router discovery, Duplicate Address Detection (DAD) process, and neighbor reachability check [FHSc]. One example is the scenario where the attacker might spoof the router advertisement (RA) message. So, he responds to a node's Router solicitation (RS) request with a spoofed RA message. Since the node does not have any means to authorize the legitimate router, it accepts the attacker's fake router prefixes and choose this attacker as its first hop router. There are some mitigation mechanism available such as IPv6 RA guard [RFC6105], first-hop security binding table, IPv6 device tracking, IPv6 port-based access list support, IPv6 global policy. These approach have some advantages and disadvantages. The disadvantages and limitations [FHSs] are as follow: - The RA guard feature does not offer protection in environments where IPv6 traffic is tunneled. - This feature is supported only in hardware by programming the TCAM. - This feature can be configured only on a switch-port interface in the ingress direction. - This feature supports only host mode. - This feature is supported only in the ingress direction; it is not supported in the egress direction. So,the assumption is that the attacker is not in local link but it is somewhere outside the network. - This feature is supported on ether channel, but not on ether channel port members. - This feature is not supported on trunk ports with merge mode. Rafiee & Meinel Expires March 9, 2015 [Page 3] INTERNET DRAFT local security Deployment September 9, 2014 - This feature cannot protect the nodes against network layer IP spoofing. - This feature is applicable against fake router advertisement attacks rather than other types of attacks that is possible in local links. One example is that the attacker can prevent the node from IP address configuration and this feature cannot prevent this attack. - This feature cannot protect the node against RA attacks if the implementation of neighbor discovery accepts unicast RA messages as well as multicast RA messages. The Neighbor Discovery specification used the word "SHOULD" and not "MUST. One of the operating system (OS) that accepts unicast RA messages is Linux distributions. - This feature might also have a patent problem since some open source operating system such as Linux did not implement it. 3. Local link Security for all nodes Mechanisms in this category would provide the node with, both, the protection against IP spoofing and also protection against rogue routers. SeND is one of the mechanism that can be classified under this category, however, it is also considered as a first-hope security mechanism. 3.1. Secure Neighbor Discovery SeND provide the local security by adding four options to Neighbor Discovery messages [RFC4861, RFC4862]. These options are timestamp, nonce, Cryptographically Generated Addresses (CGA)[RFC3972] and RSAsignature. 3.1.1. Identifying Obstacles for SeND Deployments There might be several reasons that SeND is not yet supported by many OSs. This document tries to introduce some of them. 3.1.1.1. CGA Performance and Complexity According to CGA algorithm, if the node chooses CGA sec value higher than 0, it needs to repeat some steps that needs the high CPU attention. This might limit its implementation only to the nodes that are not using battery or do not have limited resources of energy. Unfortunately, in near future, the devices are going to be more advanced and smaller in size but limited in battery. This is because the battery technology is not as advanced as the computerized devices. This is why, it is not ideal to use an approach that might use high range of CPU and energy resources. Rafiee & Meinel Expires March 9, 2015 [Page 4] INTERNET DRAFT local security Deployment September 9, 2014 3.1.1.2. CGA Security Issue Unfortunately CGA verification process allows the attacker to claim the IP address of the CGA node with CGA different sec value [cgaattack]. 3.1.1.3. Router Authorization Problem Before RPKI model was proposed, there was not any clear mechanism available to be used for router authorization. There were some solutions available but not scalable solutions. One example is that the nodes in the network are preloaded with the router's certification. This was not really ideal in the large enterprises with thousands of nodes and with different user's experience. Active Directory (AD) solves this problem but leaves the companies with the fact that they are dependent to the use of ADs. 3.2. SAVI mechanisms The purpose of SAVI mechanisms [SAVIWG] is to prevent IP spoofing attacks in the local network and does not allow an attacker to use other prefixes in this network. One of the offered solutions is the use of SeND [SAVI]. One of the assumption for this proposal is that SeND is already deployed and enabled on the nodes and after the successful verification, they generate a bindings between the port of switch that this traffic has been generated and the source IP address of the node. There are some questions unanswered in that proposal, One of these questions is that when one uses CGA or any other approaches in SeND to provide the node with the proof of IP address ownership, why one needs to use this mechanism for preventing source IP spoofing of the hosts in the network? The disadvantages of this mechanism - Like SeND, it cannot protect the node with MAC spoofing section 2.2 [SAVI], so there is no more benefit to use this mechanism. - It does not address the main problem of SeND which is trusted anchors. - If SeND is not deployed, then the assumption is the use of other protocols and monitoring systems. Therefore, the protection provided by this mechanism is similar to the FHS. 4. Recommendations for Local Security Deployments Since SeND is one of promising approach to provide the node with both local security and protect the nodes against IP spoofing attacks in Rafiee & Meinel Expires March 9, 2015 [Page 5] INTERNET DRAFT local security Deployment September 9, 2014 network layer, this section offers some possible solutions to facilitate SeND deployments. 4.1. Other Alternative Algorithms in place of CGA One possible solution to CGA problems would be the use of other alternative algorithms such as SSAS [ssasAnalysisPaper, ssasAnalysis]. It generates the IP addresses in a faster and removes the complexity. It is also ideal for nodes with limited battery resources. 4.2. Router Authorization and Preventing Layer 2 Spoofing There can be a monitoring system that stores MAC address and public key of each node. In case there is any mismatch in the network, it immediately log this event or report it to responsible person/system. To provide router authorization, this node needs to be preconfigured with the router?s MAC and public key. This is like a local Trusted Anchor (TA) that has more responsibilities. 5. Security Considerations There is no security consideration except the one that is explained for SeND. 6. IANA Considerations There is no IANA consideration 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., Mohacsi, J., "IPv6 Router Advertisement Guard," RFC 6105, February 2011. [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)," RFC 3972, March 2005. [RFC3971] Arkko, J., Kempf, J., Zill, B., and Nikander, P., "SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005. Rafiee & Meinel Expires March 9, 2015 [Page 6] INTERNET DRAFT local security Deployment September 9, 2014 [RFC4861] Narten, T., Nordmark, E., Simpson, W., Soliman, H., "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. [RFC4862] Thomson, S., Narten, T., Jinmei, T., "IPv6 Stateless Address Autoconfiguration", RFC 4862, September 2007 7.2. Informative References [FHSc] IPv6 First Hop Concerns, http://www.cisco.com/web/about/ security/intelligence/ipv6_first_hop.html [FHSs] IPv6 First Hop Security, http://www.cisco.com/en/US/docs/ios/ ipv6/configuration/guide/ip6-first_hop_security.html [cgaattack] Rafiee,H., Meinel, C., "Possible Attack on Cryptographically Generated Addresses (CGA)", http://tools.ietf.org/html/draft-rafiee-6man-cga-attack, 2014 Rafiee & Meinel Expires March 9, 2015 [Page 7] INTERNET DRAFT local security Deployment September 9, 2014 Authors' Addresses Hosnieh Rafiee HUAWEI TECHNOLOGIES Duesseldorf GmbH Riesstrasse 25, 80992, Munich, Germany Phone: +49 (0)162 204 74 58 Email: hosnieh.rafiee@huawei.com Christoph Meinel Hasso-Plattner-Institute Prof.-Dr.-Helmert-Str. 2-3 Potsdam, Germany Email: meinel@hpi.uni-potsdam.de Rafiee & Meinel Expires March 9, 2015 [Page 8]