wdiff draft-ietf-netlmm-threats-03.txt draft-ietf-netlmm-threats-04.txt

Network Working Group C. Vogt
Internet-Draft Universitaet Karlsruhe (TH)
Expires: February 22, March 16, 2007 J. Kempf
DoCoMo USA Labs
August 21,
September 12, 2006

Security Threats to Network-Based Localized Mobility Management
draft-ietf-netlmm-threats-03.txt
draft-ietf-netlmm-threats-04.txt

Status of this Memo

By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.

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.

This Internet-Draft will expire on February 22, March 16, 2007.

Abstract

This document discusses security threats to network-based localized
mobility management. Threats may occur on two interfaces: the
interface between an LMA a localized mobility anchor and a MAG, mobile access
gateway, as well as the interface between a MAG mobile access gateway and
a mobile node. Threats to the former interface impact the localized
mobility management protocol itself.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Threats to Interface between LMA and MAG . . . . . . . . . . . 4
2.1 LMA Compromise or Impersonation . . . . . . . . . . . . . 4
2.2 MAG Compromise or Impersonation . . . . . . . . . . . . . 5
2.3 Man in the Middle Attack . . . . . . . . . . . . . . . . . 7
3. Threats to Interface between MAG and Mobile Node . . . . . . . 8 7
3.1 Mobile Node Compromise or Impersonation . . . . . . . . . 8
3.2 Man in the Middle Attack . . . . . . . . . . . . . . . . . 10
4. Threats from the Internet . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 11
7. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 12 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 12
8.1 Normative References . . . . . . . . . . . . . . . . . . . 13 12
8.2 Informative References . . . . . . . . . . . . . . . . . . 13 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 14 13
A. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 14 13
Intellectual Property and Copyright Statements . . . . . . . . 17 16

1. Introduction

The network-based localized mobility management (NETLMM) architecture
[1] supports movement of IPv6 mobile nodes locally within a domain
without requiring mobility support in the mobile nodes' network
stacks. A mobile node can keep its IP address constant as it moves
from link to link, avoiding the signaling overhead and latency
associated with changing the IP address. While software Software specifically for
localized mobility management is not required on the mobile node,
whereas IP-layer movement detection software may be necessary, and
driver software for link-layer mobility is prerequisite.

The IP addresses of mobile nodes have a prefix that routes to a
localized mobility anchor (LMA). (LMA) [3]. The LMA maintains an individual
route for each registered mobile node. Any particular mobile node's
route terminates at a mobile access gateway (MAG) [3], to which the
mobile node uses as a default router on attaches at its current access link. MAGs are
responsible for updating the mobile node's route on the LMA as the
mobile node moves. A MAG detects the arrival of a mobile node on its
local access link based on handoff signaling that the mobile node
pursues. The MAG may additionally monitor connectivity of the mobile
node in order to recognize when the mobile node has left the local
access link. The localized mobility management architecture
therefore has two interfaces:

1. The interface between a MAG and an LMA where route update
signaling occurs.

2. The interface between a mobile node and its current MAG where
handoff signaling and other link maintenance signaling occurs.

The localized mobility management architecture specifies demands no
standardized specific
protocol for a MAG to detect the arrival or departure of mobile nodes on
to and from its local access link and accordingly initiate route
update signaling with the an LMA. An appropriate mechanism may be
entirely implemented at the link layer, such as is common for
cellular networks. In that case, the IP layer never detects any
movement, even when a mobile node moves from one link to another
handled by a different MAG. If the link layer does not provide the
necessary functionality, the mobile node must perform active IP-layer
movement detection signaling so as to and auto-configuration signaling, thereby
providing the trigger route for the MAG to update signaling its route at the
MAG. In either case, the decisive handoff signaling is bound to a LMA. A
mobile node identity, which is established by the localized mobility
management domain when the mobile node initially connects and
authenticates, enables the MAG to ascribe the domain. For some decisive link- or IP-
layer signaling to the correct mobile node. Some wireless access
technologies,
technologies may require the mobile node identity may have to be re-established re-
established on every link-layer handoff.

Vulnerabilities in either interface of the localized mobility
management architecture may entail new security threats which go
beyond those that already exist in IPv6. Potential attack objectives
may be to roam at the cost of a legitimate mobile node, interpose in
a mobile node's communications from a position off link, or cause
denial of service to a mobile node or to the localized mobility
management domain as a whole. This document identifies
and discusses security threats on both interfaces of the localized
mobility management architecture. It is limited to threats which are
peculiar to localized mobility management; threats to IPv6 in general
are documented in [3]. [4].

1.1 Terminology

The terminology in this document follows the definitions in [2], with
those revisions and additions from [1]. In addition, the following
definition is used:

Mobile node identity Node Identity

An identity established for the mobile node when initially
connecting to the domain. It allows the localized mobility
management domain to definitively and unambiguously identify the
mobile node upon handoff for route update signaling purposes. The
mobile node identity is conceptually independent of the mobile
node's IP or link-layer addresses, but it must be securely bound
to the mobile node's handoff signaling.

2. Threats to Interface between LMA and MAG

The localized mobility management protocol executed on the interface
between an LMA and a MAG serves to establish, update, and tear down
routes for data plane traffic of mobile nodes. Threats to this
interface can be separated into compromise or impersonation of a
legitimate LMA, compromise or impersonation of a legitimate MAG, and
man-in-the-middle attacks.

2.1 LMA Compromise or Impersonation

A compromised LMA can ignore routing route updates from a legitimate MAG,
or forge routing updates for MAG in
order to deny service to a victim mobile node node. It may also be able to trick
a legitimate MAG into creating a new, incorrect route, thereby
preparing the MAG to receive redirected traffic of a mobile node; it
may cause the traffic forwarded by a MAG to be redirected to a
different LMA; or it may simply have the MAG drop an existing route
in order to
redirect or deny the mobile node's traffic. node service. Since data plane traffic
for mobile nodes routes through the LMA, a compromised LMA can also
intercept, inspect, modify, redirect, or drop such traffic on traffic, or redirect it to a MAG
supported by
destination in collusion with the LMA. attacker. The attack can be
conducted transiently, to selectively disable traffic for any
particular mobile node or MAG at particular times.

Moreover, a compromised LMA may manipulate its routing table such
that all packets are directed towards a single MAG. This may result
in a DoS attack against that MAG and its attached access link.

These threats also emanate from an attacker which tricks a MAG into
believing that it is a legitimate LMA. This attacker can cause the
MAG to conduct route update signaling with the attacker instead of
with the legitimate LMA, enabling it to ignore route updates from the
MAG, or forge induce incorrect route updates changes at the MAG as described above,
in order to redirect or deny a victim mobile node's traffic. The attacker
does not necessarily have to be on the original control plane path
between the legitimate LMA and the MAG, provided that it can somehow
make its presence known to the MAG.
E.g., the IP address of a mobility anchor point in hierarchical
Mobile IPv6 mobility management [4] may be proliferated across a
domain hop by hop in Router Advertisement messages. Failure to
properly mutually authenticate
when establishing an association between an LMA and a comparable mechanism for localized mobility
management MAG would allow
an attacker to establish itself as a rogue LMA.

The attacker may further be able to intercept, inspect, modify,
redirect, drop,
or drop redirect data plane traffic to and from a mobile node. This is
obvious if the attacker is on the original data plane path between
the legitimate LMA and the mobile node's current MAG, which may
happen independent independently of whether or not the attacker is on the original
control plane path. If the attacker is not on this path, it may be
able to leverage the localized mobility management protocol to
redefine the prefix that the mobile node uses in IP address
configuration. The attacker can then specify a prefix that routes to
itself. Whether or not outgoing data plane packets sourced by the
mobile node can be interfered with by an attacker off the original
data plane path depends on the specific data plane forwarding
mechanism within the localized mobility management domain. E.g., if
IP-in-IP encapsulation or an equivalent per-mobile-node approach is used for outbound
data plane packets, the packets will route can be forced to be routed through
the attacker. On the other hand, standard IP routing may cause the
packets to be relayed via the a legitimate LMA and hence to circumvent
the attacker.

2.2 MAG Compromise or Impersonation

A compromised MAG can redirect a victim mobile node's traffic onto its local
access link arbitrarily, without authorization from the mobile node.
This threat is similar to an attack on a typical routing protocol
where a malicious stub router injects a bogus host route for the
mobile node. In general, forgery of a subnet prefix in link state or
distance vector routing protocols requires support of multiple
routers in order to obtain a meaningful change in forwarding
behavior. But a bogus host route is likely to take precedence over
the routing information advertised by legitimate routers, which is
usually less specific, hence the attack should succeed even if the
attacker is not supported by other routers. A difference between
redirection in a routing protocol and redirection in localized
mobility management is that the former impacts the routing tables of
multiple routers, whereas the latter involves only the compromised
MAG and an LMA.

Moreover, a compromised MAG can ignore the presence of a mobile node
on its local access link and refrain from registering the mobile node
at an LMA. The mobile node then loses its traffic. The compromised
MAG may further be able to cause interruption to a mobile node by
deregistering the mobile node at the serving LMA, pretending that the
mobile node has powered down. The mobile node then needs to reinitiate re-
initiate the network access authentication procedure, which the
compromised MAG may prevent repeatedly until the mobile node moves to
a different MAG. The mobile node should be able to handle this
situation, but the recovery process may be lengthy and hence impair
ongoing communication sessions to a significant extent.

Attacks that the MAG can mount on its access link interface are
common for any regular IPv6 access router [3].

Denial of service against an LMA is another threat of MAG subversion.
The compromised MAG can trick the an LMA into believing that a high
number of mobile nodes have attached to the MAG. The LMA will then
establish a routing table entry for each of the non-existing mobile
nodes. The unexpected growth of the routing table may eventually
cause the LMA to reject legitimate route update requests. It may
also decrease the forwarding speed for data plane packets due to
higher route lookup latencies, and it may for the same reason slow
down the responsiveness to control plane packets. Another adverse
side effect of a high number of routing table entries is that the
LMA, and hence the localized mobility management domain as a whole,
becomes more susceptible to flooding packets from external attackers
(see Section 4). The high number of superfluous routes increases the
probability that a flooding packet, sent to a random IP address
within the localized mobility management domain, matches an existing
routing table entry at the LMA and gets tunneled to a MAG, which in
turn performs address resolution [5] on the local access link. At the
same time, fewer flooding packets can be dropped directly at the LMA due to
on the basis of a nonexistent routing table entry.

All of these threats apply not just to a MAG that is compromised, but
also to an attacker that manages to counterfeit the identity of an
authorized a
legitimate MAG in interacting with both mobile nodes and an LMA.
Such an attacker can behave towards mobile nodes like a legitimate an authorized
MAG and engage an LMA in route update signaling. In a related
attack, the perpetrator eavesdrops on signaling packets exchanged
between an authorized a legitimate MAG and an LMA and replays these packets at a
later time. These attacks may be conducted transiently, to
selectively disable traffic for any particular mobile node at
particular times.

2.3 Man in the Middle Attack

An attacker that manages to interject itself between a legitimate LMA
and a legitimate MAG can act as a man in the middle with respect to
both control plane signaling and data plane traffic. If the attacker
is on the original control plane path, it can forge, modify, or drop
route update packets so as to cause the establishment of incorrect
routes or the removal of routes that are in active use. Similarly,
an attacker on the original data plane path can intercept, inspect,
modify, redirect, drop, and drop redirect data plane packets sourced by or destined
to a victim mobile node.

A compromised switch or router located between an LMA and a MAG may can
cause similar damage. Any switch or router on the control plane path
can forge, modify, or drop control plane packets, and thereby
interfere with route establishment. Any switch or router on the data
plane path can intercept, inspect, modify, and drop data plane
packets, or rewrite IP headers so as to divert the packets from their
original path.

An attacker between an LMA and a MAG may further impersonate the MAG
towards the LMA and vice versa in route update signaling. The
attacker can so interfere with route establishment even if it is not
on the original control plane path between the LMA and the MAG. An
attacker off the original data plane path may undertake the same to
cause inbound data plane packets destined to the mobile node to be
routed first from the LMA to the attacker, and from there to the
mobile node's MAG and finally to the mobile node itself. As
explained in Section 2.1, here, too, it depends on the specific data
plane forwarding mechanism within the localized mobility management
domain whether or not the attacker can influence the route of
outgoing data plane packets sourced by the mobile node.

3. Threats to Interface between MAG and Mobile Node

A MAG monitors the mobile nodes' link-layer handoff signaling or IP-
layer movement detection signaling in order to detect the arrival and departure of mobile nodes to and accordingly initiate route updates with
the LMA. Cellular from
its local access technologies utilize only the signaling at
the wireless link layer, and the IP stack never sees any change when
the mobile node moves from one MAG to a MAG based on a different link. For
non-cellular access technologies, such as IEEE 802.11 link- or wired
Ethernet, the link-layer signaling may not hide a handoff from the IP
layer. Instead, IP-layer movement detection mechanisms.
Whatever signaling may have to be
performed in response to a notification from on the access link layer that a
change in link-layer attachment has occurred. This signaling may
involve extensions [6] for IPv6 Neighbor Discovery [5], DHCPv6 [7],
or additional technology-specific functionality at the IP layer.

Although the mobile node identity is conceptually independent of the
mobile node's IP or link-layer addresses in either case, it thereby decisive must be
securely bound to whatever handoff signaling of the mobile node is
decisive for route updates on the MAG-LMA interface, be it via an
address or otherwise. identity. A MAG uses this binding
to deduce when the
mobile node has handed over onto ascribe the MAG's local access link, and
possibly when signaling to the mobile node leaves the local access link again,
thereby providing the trigger for and accordingly initiate
route update signaling to with an LMA. The binding must be robust to
spoofing because it would otherwise facilitate impersonation of the
mobile node by a third party, denial of service, or man-in-the-middle
attacks.

3.1 Mobile Node Compromise or Impersonation

An attacker that is able to forge the mobile node identity of a
neighboring victim
mobile node may be able can to trick its a MAG into redirecting the mobile node's data plane packets to itself. Such an on-link
attack is common
for any regular IPv6 network [3]. However, if
handoff signaling cannot definitively and unambiguously be linked
back to the legitimate mobile node identity, an attacker may further
be capable of fabricating handoff signaling of a victim mobile node
that currently attaches to a different link. the attacker. The attacker can thus
trick its MAG into believing launch such an
impersonation attack against a mobile node that resides on the same
link as the attacker, or against a mobile node has handed over
onto the MAG's access on a different link. The MAG will then initiate route update
signaling to an LMA, causing
If the LMA to redirect inbound data plane attack is on-link, the redirection of packets for from the mobile
node to the attacker's MAG and finally to the
attacker itself. The attacker can so examine the packets that
legitimately belong is internal to the mobile node, or discard MAG, and it involves no route
update signaling between the packets MAG and an LMA. On-link attacks are
possible in
order to deny the mobile node service. The same can happen if a MAG
accepts from regular IPv6 network [4] that does not use Secure
Neighbor Discovery [5].

Off-link impersonation requires the attacker replayed to fabricate handoff
signaling packets which of the attacker has previously recorded from mobile node and thus trick the MAG into believing
that the legitimate mobile node. node has handed over onto the MAG's access link. The above
attack is conceivable both if the attacker and the mobile node are on
separate links that connect to different MAGs, as well as if they are
on separate separate, possibly virtual per-mobile-node links connecting that connect to
the same MAG. In the former case, two MAGs would think they see the
mobile node and both would independently perform route update
signaling with the LMA. In the latter case, route update signaling
is likely to be performed only once, and the redirection of packets
from the mobile node to the attacker is internal to the MAG. The
mobile node can always recapture its traffic back from the attacker
through another run of handoff signaling. But standard mobile nodes
are generally not prepared to counteract this kind of attack, and
even where network stacks include suitable functionality, the attack
may not be noticeable early enough at the link or IP layer to quickly
institute countermeasures. The attack is therefore disruptive at a
minimum, and may potentially persist until the mobile node initiates
signaling again upon a subsequent handoff.

Off-link impersonation

Impersonation attacks can be prevented at the link layer.
E.g., they are not possible layer,
particularly with cellular access technologies, technologies where the handoff signaling
between the mobile node and the network must be authenticated and is
completely controlled by the wireless link layer. Here, an attacker must be on the same link as the victim
mobile node in order to disrupt the negotiation between the mobile
node and the network. Cellular access
technologies also provide
other a variety of cryptographic and non-cryptographic
attack barriers at the link
layer, layer which make mounting mouting an impersonation
attack, both on-link and off-link, very difficult. For non-cellular access technologies,
however, off-link However, for non-
cellular technologies that do not require link layer authentication
and authorization during handoff, impersonation attacks may be
possible.

An attacker which that can forge handoff signaling messages may also cause denial of
service against the localized mobility management domain. The
attacker can trick a MAG into believing that a large number of mobile
nodes have attached to the local access link and thus induce it to
initiate route update signaling with an LMA for each mobile node
assumed on link. The result of such an attack is both superfluous
signaling overhead on the control plane as well as a high number of
needless entries in the LMA's and MAG's routing tables. The
unexpected growth of the routing tables may eventually cause the LMA
to reject legitimate route update requests, and it may cause the MAG
to ignore handoffs of legitimate mobile nodes on onto its local access
link. It may also decrease the LMA's and MAG's forwarding speed for
inbound and outbound data plane packets due to higher route lookup
latencies, and it may for the same reason slow down their
responsiveness to control plane packets. An adverse side effect of
this attack is that the LMA, and hence the localized mobility
management domain as a whole, becomes more susceptible to flooding
packets from external attackers (see Section 4). The high number of
superfluous routes increases the probability that a flooding packet,
sent to a random IP address within the localized mobility management
domain, matches an existing routing table entry at the LMA and gets
tunneled to a MAG, which in turn performs address resolution [5] on the
local access link. At the same time, fewer flooding packets can be
dropped directly at the LMA due to on the basis of a nonexistent routing
table entry.

A threat related to the ones identified above, but not limited to
handoff signaling, is IP spoofing [8][9]. [6]. Attackers use IP spoofing
mostly for reflection attacks or to hide their identities. The
threat can be reasonably contained by a wide deployment of network
ingress filtering [10] [7] in routers, especially within access network routers. networks.
This technique prevents IP spoofing to the extent that it ensures
topological correctness of IP source address prefixes in to-be-forwarded to-be-
forwarded packets. Where the technique is deployed in an access
router, packets are forwarded only if the prefix of their IP source
address is valid on the router's local access link. An attacker can
still use a false interface identifier in combination with an on-link
prefix. But since reflection attacks typically aim at off-link
targets, and the enforcement of topologically correct IP address
prefixes also limits the effectiveness of identity concealment,
network ingress filtering has proven adequate so far. On the other
hand, prefixes are not limited to a specific link in a localized
mobility management domain, so merely ensuring topological
correctness through ingress filtering becomes insufficient. An
additional mechanism for IP address ownership verification is
necessary to prevent an attacker may be able to send from sending packets with an off-link off-
link IP source
address despite the presence of network ingress filtering. This
could make IP spoofing again more attractive. address.

3.2 Man in the Middle Attack

An attacker which can interpose between a victim mobile node and a MAG
during link- and/or IP-layer handoff signaling, router discovery, and IP address
configuration can signaling may be able to mount a
man-in-the-middle attack on the mobile node, spoofing the mobile node
into believing that it has a legitimate connection with the localized
mobility management domain. The attacker can thus intercept,
inspect, modify, or selectively drop data plane packets sourced by or destined to
the mobile node.

4. Threats from the Internet

A localized mobility management domain uses individual host routes
for data plane traffic of different mobile nodes, each between an LMA
and hence deviates from the standard IPv6 longest-
prefix-match routing. a MAG. Creation, maintenance, and deletion of tese
host these routes in addition cause
control traffic within the localized mobility management domain.
These characteristics are transparent to mobile nodes as well as
external correspondent nodes, but the functional differences within
the domain may influence the impact that a denial-of-service attack
from the outside world can have on the domain.

A denial-of-service attack on an LMA may be launched by sending
packets to arbitrary IP addresses which that are potentially in use by
mobile nodes within the localized mobility management domain. Like a
border router, the LMA is in a topological position through which a
substantial amount of data plane traffic goes, so it must process the
flooding packets and perform a routing table lookup for each of them.
The LMA can discard packets for which the IP destination address is
not registered in its routing table. But other packets must be
encapsulated and forwarded. A target MAG as well as any mobile nodes
attached to the that MAG's local access link are also likely to suffer
damage because the unrequested packets must be decapsulated and
consume link bandwidth as well as processing capacities on the
receivers. This threat is in principle the same as for denial of
service on a regular IPv6 border router, but because either the routing
table lookup enables lookups may enable the LMA to drop a part of the flooding packet packets
early on or, on the contrary, additional tunneling workload is required,
required for packets that cannot be dropped, the impact of an attack
against localized mobility management may be different.

In a related attack, the villain attacker manages to obtain a globally
routable IP address of an LMA or a different network entity within
the localized mobility management domain and perpetrates a denial-of-
service attack against that IP address. Localized mobility
management is in general somewhat resistant to such an attack because
mobile nodes need never obtain a globally routable IP address of any
entity within the localized mobility management domain. A
compromised mobile node hence cannot pass such an IP address off to a
remote attacker, limiting the feasibility of extracting information
on the topology of the localized mobility management domain. It is
still possible for an attacker to perform IP address scanning if MAGs
and LMAs have globally routable IP addresses, but the much larger
IPv6 address space makes scanning considerably more time consuming.

5. Security Considerations

This document describes threats to network-based localized mobility
management. These may either occur on the interface between an LMA
and a MAG, or on the interface between a MAG and a mobile node.
Mitigation measures for the threats, as well as the security
considerations associated with those measures, are described in the
respective protocol specifications [11][12] [3][8] for the two interfaces.

6. IANA Considerations

This document has no actions for IANA.

7. Acknowledgment

The authors would like to thank the NETLMM working group, especially
Jari Arkko, Gregory Daley, Vijay Devarapalli, Lakshminath Dondeti,
Gerardo Giaretta, Wassim Haddad, Andy, Huang, Dirk von Hugo, Julien
Laganier, Henrik Levkowetz, Vidya Narayanan, Phil Roberts, and Pekka
Savola (in alphabetical order) for valuable comments and suggestions
regarding this document.

8. References

8.1 Normative References

[1] Kempf, J., "Problem Statement for Network-based Localized
Mobility Management", IETF Internet Draft
draft-ietf-netlmm-nohost-ps-04.txt (work in progress),
June 2006.

[2] Manner, J. and M. Kojo, "Mobility Related Terminology",
IETF Request for Comments 3753, June 2004.

8.2 Informative References

[3] Giaretta, G., "NetLMM Protocol", IETF Internet Draft
draft-giaretta-netlmm-dt-protocol-00.txt (work in progress),
June 2006.

[4] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
Discovery (ND) Trust Models and Threats", IETF Request for
Comments 3756, May 2004.

[4] Soliman, H., Castelluccia, C., El Malki, K., and L. Bellier,
"Hierarchical Mobile IPv6 Mobility Management (HMIPv6)",
IETF Request for Comments 4140, August 2005.

[5] Narten, T., "Neighbor Discovery for IP version 6 (IPv6)",
IETF Internet Draft draft-ietf-ipv6-2461bis-07.txt (work in
progress), May 2006.

[6] Kempf, Arkko, J., Narayanan, S., Nordmark, E., Pentland, B., and JH.
Choi, "Detecting Network Attachment in IPv6 Networks (DNAv6)",
IETF Internet Draft draft-ietf-dna-protocol-01.txt (work in
progress), June 2006.

[7] Droms, R., Bound, Kempf, J., Volz, Zill, B., Lemon, T., E., C., and M.
Carney, "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", P. Nikander, "SEcure
Neighbor Discovery (SEND)", IETF Request for Comments 3315, July 2003.

[8] 3971,
March 2005.

[6] CERT Coordination Center, "CERT Advisory CA-1996-21 TCP SYN
Flooding and IP Spoofing Attacks", September 1996.

[9] CERT Coordination Center, "CERT Advisory CA-1998-01 Smurf IP
Denial-of-Service Attacks", January 1998.

[10]

[7] Ferguson, P. and D. Senie, "Network Ingress Filtering: Defeating
Denial of Service Attacks which employ IP Source Address
Spoofing", IETF Request for Comments 2827, May 2000.

[11] Giaretta, G., "NetLMM Protocol", IETF Internet Draft
draft-giaretta-netlmm-dt-protocol-00.txt (work in progress),
June 2006.

[12]

[8] Laganier, J., Narayanan, S., and F. Templin, "Network-based
Localized Mobility Management Interface between Mobile Node and
Access Router", IETF Internet Draft
draft-ietf-netlmm-mn-ar-if-01.txt (work in progress), June 2006.

[13] Aura, T., "Cryptographically Generated Addresses (CGA)",
IETF Request for Comments 3972, March 2005.

[14] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network
Access Identifier", IETF Request for Comments 4282,
December 2005.

Authors' Addresses

Christian Vogt
Institute of Telematics
Universitaet Karlsruhe (TH)
P.O. Box 6980
76128 Karlsruhe
Germany

Email: chvogt@tm.uka.de

James Kempf
DoCoMo USA Labs
181 Metro Drive, Suite 300
San Jose, CA 95110
USA

Phone: +1 408 451 4711
Email: kempf@docomolabs-usa.com

Appendix A. Change Log

The following is a list of technical changes that were made from
version 03 to version 04 of the document. Editorial revisions are
not explicitly mentioned.

o Section 2.1: Clarified in first paragraph what it means for a
compromised LMA to "forge routing updates for a victim mobile
node" and what the intention behind such an attack could be.

o Section 2.1: Removed description of how MAP discovery works in
Hierarchical Mobile IPv6.

o Section 3: Introductory text shortened, because (i) it repeated
material from Section 1, and (ii) also described potential link-
layer technologies for access links, which was not within the
scope of this document.

o Section 3.1: Clarified how impersonation of a mobile node may
look like when the attacker attaches to the same MAG as the mobile
node, but to a different link.

o Section 3.1: Revised text on why cellular technologies can
prevent impersonation attacks against mobile nodes at the link
layer.

The following is a list of technical changes that were made from
version 02 to version 03 of the document. Editorial revisions are
not explicitly mentioned.

o Changed the terminology from "network access identity" to "mobile
node identity" as the previous term was frequently confused with
the different "network access identifier" (NAI). Removed the
special "Network Access Identity" subsection in Section 3. The
mobile node identity is now first mentioned in Section 1, which
fits well with the nutshell description of the NETLMM
architecture. The security requirements of the mobile node
identifier are discussed in the introductory text of Section 3.
This makes more sense than a special subsection because the text,
on one hand, provides the necessary basis to understand the
following subsections, while on the other hand, it does not really
explain an attack itself.

o Section 1: Extended the description of conceptual actors in the
localized mobility management architecture and added a summary of
potential attack objectives and attack targets.

o Section 3.1: Granularity of ingress filtering may be coarser in a
localized mobility mangement management domain. It may also allow off-link
IP spoofing since prefixes are not limited to a specific link.

o Section 2.2: The threat of replay attacks was not mentioned in
this section. It was added.

o Section 3.1: The threat of replay attacks was not mentioned in
this section. It was added.

o Section 2.2: Causing spurious route updates may lead to DoS
against the localized mobility management domain. This threat was
missing in the discussion of this section and it was added.

o Section 3.1: Causing spurious route updates may lead to DoS
against the localized mobility management domain. This threat was
missing in the discussion of this section and it was added.

o Section 4: Moved DoS attack against a localized mobility
management domain from the Internet to a separate section because
it is not specific to either interface within the domain.

o Revised the document with respect to the recent agreement the
addressing model.

o Revised the document with respect to the the possibility that
there may be more than one LMA. The text was initially written
under the assumption that the LMA is unique.

o References split into normative and informative references.

The following is a list of technical changes that were made from
version 01 to version 02 of the document. Editorial revisions are
not explicitly mentioned.

o Section 2.1: Included DoS/flooding attack against MAG. Also
clarified how a malicious node off the control plane path between
the authorized LMA and one or multiple target MAGs could
impersonate the authorized LMA against the MAGs. Such an attacker
could use various means to interfere with data plane traffic even
if it is off the original data plane path between the legitimate
LMA and the MAGs.

o Section 2.2: Malicious MAG may deregister an actively
communicating mobile node, without consent of the mobile node.

o Section 2.3: Included related threats pertaining to MITM between
LMA and MAG, which were formerly described in other sections.

o Section 4: Included description of DoS/flooding attack against
LMA, including its impact on the target MAGs, their links, and the
target mobile nodes.

o Section 3: Revised the structure of this section. Threats are
now divided into attacks against a mobile node's network access
identity; impersonation of a mobile node, both from the mobile
node's link and from off link; as well as man-in-the-middle
attacks.

o Section 1: The binding with the network access identity may be
with the authentication keys associated with the mobile node's IP
address, not necessarily with the IP addresses themselves.

o Section 3.1: Off-link attack may be mounted from a link that
connects to a different MAG than the victim mobile node's MAG.

Intellectual Property Statement

The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights 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; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.

Copies of IPR disclosures made to the IETF Secretariat 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 on-line IPR repository at
http://www.ietf.org/ipr.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.

The IETF has been notified of intellectual property rights claimed in
regard to some or all of the specification contained in this
document. For more information consult the online list of claimed
rights.

Disclaimer of Validity

This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM 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.

Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.

Acknowledgment

Funding for the RFC Editor function is currently provided by the
Internet Society.