Internet DRAFT - draft-rafiee-6man-local-security
draft-rafiee-6man-local-security
Networking Group H. Rafiee
INTERNET-DRAFT
Intended status: Informational
Expires: November 8, 2015 May 8, 2015
Recommendations for Local Security Deployments
<draft-rafiee-6man-local-security-03.txt>
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
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This Internet-Draft will expire on November 8, 2015.
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the Trust Legal Provisions and are provided without warranty as
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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 . . . . . . . 6
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
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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.
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- 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.
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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 Resource Public Key Infrastructure (RPKI) [RFC6810] 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].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 algorithm in
SeND options to provide the node with the proof of IP address
ownership, how this mechanism can be helpful to provide this
assurance? SAVI-send mechanism is similar to Trust in First Use
(TIFU) mechanisms. otherwise the switch is configured manually with
the router in the network so that it can only be useful for router
authorization. Because for the proof of IP address ownership, it is
CGA or other similar algorithm that can help.
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 otherwise manually configure the switch.
- 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.
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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
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 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 the matching of 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.
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[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.
[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
[RFC6810] Bush, R., Austein, R.,"The Resource Public Key
Infrastructure (RPKI) to Router Protocol" , RFC6810,
January 2013
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,
2015
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Authors' Addresses
Hosnieh Rafiee
http://www.rozanak.com
Munich, Germany
Phone: +49 (0)162 204 74 58
Email: ietf@rozanak.com
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