Security Threats for NHDP
draft-ietf-manet-nhdp-sec-threats-02
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (manet WG) | |
|---|---|---|---|
| Authors | Ulrich Herberg , Jiazi Yi , Thomas H. Clausen | ||
| Last updated | 2013-03-20 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text htmlized pdfized bibtex | ||
| Reviews |
SECDIR Early review
(of
-03)
Has Nits
|
||
| Stream | WG state | In WG Last Call | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-manet-nhdp-sec-threats-02
Mobile Ad hoc Networking (MANET) U. Herberg
Internet-Draft Fujitsu Laboratories of America
Intended status: Informational J. Yi
Expires: September 21, 2013 T. Clausen
LIX, Ecole Polytechnique
March 20, 2013
Security Threats for NHDP
draft-ietf-manet-nhdp-sec-threats-02
Abstract
This document analyses common security threats of the Neighborhood
Discovery Protocol (NHDP), and describes their potential impacts on
MANET routing protocols using NHDP.
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/.
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."
This Internet-Draft will expire on September 21, 2013.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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.
Herberg, et al. Expires September 21, 2013 [Page 1]
Internet-Draft Security Threats for NHDP March 2013
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. NHDP Threat Overview . . . . . . . . . . . . . . . . . . . . . 4
4. Detailed Threat Description . . . . . . . . . . . . . . . . . 4
4.1. Jamming . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Denial of Service Attack . . . . . . . . . . . . . . . . . 5
4.3. Eavesdropping . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Incorrect HELLO Message Generation . . . . . . . . . . . . 6
4.4.1. Identity Spoofing . . . . . . . . . . . . . . . . . . 6
4.4.2. Link Spoofing . . . . . . . . . . . . . . . . . . . . 7
4.5. Replay Attack . . . . . . . . . . . . . . . . . . . . . . 8
4.6. Message Timing Attacks . . . . . . . . . . . . . . . . . . 8
4.6.1. Interval Time Attack . . . . . . . . . . . . . . . . . 8
4.6.2. Validity Time Attack . . . . . . . . . . . . . . . . . 9
4.7. Indirect Jamming . . . . . . . . . . . . . . . . . . . . . 9
4.8. Attack on Link Quality Update . . . . . . . . . . . . . . 10
5. Impact of inconsistent Information Bases on Protocols
using NHDP . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. MPR Calculation . . . . . . . . . . . . . . . . . . . . . 11
5.1.1. Flooding Disruption due to Identity Spoofing . . . . . 11
5.1.2. Flooding Disruption due to Link Spoofing . . . . . . . 12
5.1.3. Broadcast Storm . . . . . . . . . . . . . . . . . . . 13
5.2. Routing Loops . . . . . . . . . . . . . . . . . . . . . . 14
5.3. Invalid or Non-Existing Paths to Destinations . . . . . . 14
5.4. Data Sinkhole . . . . . . . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Herberg, et al. Expires September 21, 2013 [Page 2]
Internet-Draft Security Threats for NHDP March 2013
1. Introduction
The Neighborhood Discovery Protocol (NHDP) [RFC6130] allows routers
to acquire topological information up to two hops away from
themselves, by way of periodic HELLO message exchanges. The
information acquired by NHDP is used by other protocols, such as
OLSRv2 [OLSRv2] and SMF [RFC6621]. The topology information,
acquired by way of NHDP, serves these routing protocols for
calculating paths to all destinations in the MANET, for relay set
selection for network-wide transmissions, etc.
As NHDP is typically used in wireless environments, it is potentially
exposed to different kinds of security threats, some of which are of
particular significance as compared to wired networks. As wireless
radio waves can be captured as well as transmitted by any wireless
device within radio range, there is commonly no physical protection
as otherwise known for wired networks. NHDP does not define any
explicit security measures for protecting the integrity of the
information it acquires, however suggests that this be addressed in a
fashion appropriate to the deployment of the network.
This document is based on the assumption that no additional security
mechanism (such as IPsec) is used in the IP layer. The document
analyses possible attacks and mis-configurations on NHDP and outlines
the consequences of such attacks/mis-configurations to the state
maintained by NHDP in each router (and, thus, made available to
protocols using this state).
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
This document uses the terminology and notation defined in [RFC5444]
and NHDP [RFC6130].
Additionally, this document introduces the following terminology:
NHDP Router: A MANET router, running NHDP as specified in [RFC6130].
Attacker: A device, present in the network and which intentionally
seeks to compromise the information bases in NHDP routers.
Herberg, et al. Expires September 21, 2013 [Page 3]
Internet-Draft Security Threats for NHDP March 2013
Compromised NHDP Router: An attacker, present in the network and
which generates syntactically correct NHDP control messages.
Control messages emitted by a Compromised NHDP router may contain
additional information, or omit information, as compared to a
control message generated by a non-compromized NHDP router located
in the same topological position in the network.
Legitimate NHDP Router: An NHDP router, which is not a Compromised
NHDP Router.
3. NHDP Threat Overview
NHDP defines a HELLO messages exchange, enabling each NHDP router to
acquire topological information describing its 1-hop and 2-hop
neighbors, and specifies information bases for recording this
information.
An NHDP router periodically transmits HELLO messages using a link-
local multicast on each of its interfaces with a hop-limit of 1
(i.e., HELLOs are never forwarded). In these HELLO messages, an NHDP
router announces the IP addresses as heard, symmetric or lost
neighbor interface addresses.
An Attacker has several ways of harming this neighbor discovery
process: It can announce "wrong" information about its identity,
postulate non-existent links, and replay HELLO messages. These
attacks are presented in detail in Section 4.
The different ways of attacking an NHDP deployment may eventually
lead to inconsistent information bases, not accurately reflecting the
correct topology of the MANET. The consequence hereof is that
protocols using NHDP will base their operation on incorrect
information, causing routing protocols to not be able to calculate
correct (or any) paths, degrade the performance of flooding
operations based on reduced relay sets, etc. These consequences to
protocols using NHDP are described in detail in Section 5.
4. Detailed Threat Description
For each threat, described in the below, a description of the
mechanism of the corresponding attack is given, followed by a
description of how the attack affects NHDP. The impacts from each
attack on protocols using NHDP are given in Section 5.
For simplicity in the description, examples given assume that NHDP
routers have a single interface with a single IP address configured.
Herberg, et al. Expires September 21, 2013 [Page 4]
Internet-Draft Security Threats for NHDP March 2013
All the attacks apply, however, for NHDP routers with multiple
interfaces and multiple addresses as well.
4.1. Jamming
One vulnerability, common for all protocols operating a wireless ad
hoc network, is that of "jamming", i.e., that a device generates
massive amounts of interfering radio transmissions, which will
prevent legitimate traffic (e.g.,control traffic as well as data
traffic) on part of a network.
Depending on lower layers, this may not affect transmissions: HELLO
messages from an NHDP router with "jammed" interfaces may be received
by other NHDP routers. As NHDP identifies whether a link to a
neighbor is uni-directional or bi-directional, a routing protocol
that uses NHDP for neighborhood discovery may ignore a link from a
jammed NHDP router to a non-jammed NHDP router. The jammed router (a
router with jammed carrier) would appear simply as "disconnected" for
the un-jammed part of the network - which is able to maintain
accurate topology maps.
If, due to a jamming attack, a considerable amount of HELLO messages
are lost or corrupted due to collisions, neighbor NHDP routers are
not able to establish links between them any more. Thus, NHDP will
present empty information bases to the protocols using it.
4.2. Denial of Service Attack
A Denial of Service (DoS) attack can be a result of misconfiguration
of Legitimate NHDP Routers (e.g., very short HELLO transmission
interval) or malicious behavior of Compromised NHDP Routers.
By transmitting a huge amount of HELLO messages in a short period of
time, NHDP Routers can jam the communication channel as introduced in
Section 4.1. Furthermore, a Compromised NHDP Router can spoof a
large amount of different IP addresses, and send HELLOs to its
neighbors to fill their Link/Neighbor Sets. This may result in
memory overflow, and makes the processing of legitimate HELLO
messages impossible. A Compromised NHDP Router can also use link
spoofing in its HELLO messages, generating huge 2-hop Sets in
adjacent NHDP Routers and therefore potentially a memory overflow.
Moreover, protocols such as SMF and OLSRv2, using the 2-hop
information for MPR calculation, may exhaust the available
computational resources of the router if the Neighbor Set and 2-hop
Sets have too many entries.
By exhausting the memory, CPU, or (and) channel resources of a router
in a DoS attack or a misconfiguration, NHDP Routers may not be able
Herberg, et al. Expires September 21, 2013 [Page 5]
Internet-Draft Security Threats for NHDP March 2013
to accomplish their specified tasks of exchanging 1-hop and 2-hop
neighborhood information, and thereby disturbing the operation of
routing protocols using NHDP.
4.3. Eavesdropping
Eavesdropping is a common and easy passive attack in a wireless
environment. Once a packet is transmitted, any adjacent NHDP router
can potentially obtain a copy, for immediate or later processing.
Neither the source nor the intended destination can detect this. A
malicious NHDP router can eavesdrop on the NHDP message exchange and
thus learn the local topology. It may also eavesdrop on data traffic
to learn source and destination addresses of data packets, or other
header information, as well as the packet payload.
Eavesdropping does not pose a direct threat to the network nor to
NHDP, in as much as that it does not alter the information recorded
by NHDP in its information bases and presented to other protocols
using it, but it can provide network information required for
enabling other attacks, such as the identity of communicating NHDP
routers, link characteristic, NHDP router configuration, etc.
4.4. Incorrect HELLO Message Generation
An NHDP router performs two distinct tasks: it periodically generates
HELLO messages, and it processes incoming HELLO messages from
neighbor NHDP routers. This section describes security attacks
involving the HELLO generation.
4.4.1. Identity Spoofing
Identity spoofing implies that a Compromised NHDP router sends HELLO
messages, pretending to have the identity of another NHDP router, or
even a router that does not exist in the networks. A Compromised
NHDP router can accomplish this by using another IP address in an
address block of a HELLO message, and associating this address with a
LOCAL_IF Address Block TLV.
An NHDP router receiving the HELLO message from a neighbor, will
assume that it originated from the NHDP router with the spoofed
interface address. As a consequence, it will add a Link Tuple to
that neighbor with the spoofed address, and include it in its next
HELLO messages as a heard neighbor (and possibly as symmetric
neighbor after another HELLO exchange).
Identity spoofing is particular harmful if a Compromised NHDP router
spoofs the identity of another NHDP router that exists in the same
routing domain. With respect to NHDP, such a duplicated, spoofed
Herberg, et al. Expires September 21, 2013 [Page 6]
Internet-Draft Security Threats for NHDP March 2013
address can lead to an inconsistent state up to two hops from an NHDP
router. Figure 1 depicts a simple example. In that example, NHDP
router A is in radio range of C, but not of the Compromised NHDP
router X. If X spoofs the address of A, that can lead to conflicts
for routing protocol that uses NHDP, and therefore for wrong path
calculations as well as incorrect data traffic forwarding.
.---. .---. .---.
| A |----| C |----| X |
'---' '---' '---'
Figure 1
Figure 2 depicts another example. In this example, A is two hops
away from NHDP router C, reachable through NHDP router B. If the
Compromised NHDP router X spoofs the address of A, D will take A as
its one hop neighbor, and C may think that A is indeed reachable
through NHDP router D.
.---. .---. .---. .---. .---.
| A |----| B |----| C |----| D |----| X |
'---' '---' '---' '---' '---'
Figure 2
4.4.2. Link Spoofing
Similar to identity spoofing, link spoofing implies that a
Compromised NHDP router sends HELLO messages, signaling an incorrect
set of neighbors. This may take either of two forms:
o A Compromised NHDP Router can postulate addresses of non-present
neighbor NHDP routers in an address block of a HELLO, associated
with LINK_STATUS TLVs.
o A Compromised NHDP router can "ignore" otherwise existing
neighbors by not advertising them in its HELLO messages.
The effect of link spoofing with respect to NHDP are twofold,
depending on the two cases mentioned above: If the Compromised NHDP
router ignores existing neighbors in its advertisements, links will
be missing in the information bases maintained by other routers, and
there may not be any connectivity to or from these NHDP routers to
others NHDP routers in the MANET. If, on the other hand, the
Compromised NHDP router advertises non-existing links, this will lead
to inclusion of topological information in the information base,
describing non-existing links in the network (which, then, may be
used by other protocols using NHDP in place of other, existing,
Herberg, et al. Expires September 21, 2013 [Page 7]
Internet-Draft Security Threats for NHDP March 2013
links).
4.5. Replay Attack
A replay attack implies that control traffic from one region of the
network is recorded and replayed in a different region at (almost)
the same time, or in the same region at a different time. This may,
for example, happen when two Compromised NHDP routers collaborate on
an attack, one recording traffic in its proximity and tunneling it to
the other Compromised NHDP router, which replays the traffic. In a
protocol where links are discovered by testing reception, this will
result in extraneous link creation (basically, a "virtual" link
between the two Compromised NHDP routers will appear in the
information bases of neighboring NHDP routers).
While this situation may result from an attack, it may also be
intentional: if data-traffic also is relayed over the "virtual" link,
the link being detected is indeed valid for use. This is, for
instance, used in wireless repeaters. If data traffic is not carried
over the virtual link, an imaginary, useless, link between the two
Compromised NHDP routers, has been advertised, and is being recorded
in the information bases of their neighboring NHDP routers.
4.6. Message Timing Attacks
In NHDP, each HELLO message contains a "validity time" and may
contain an "interval time" field, identifying the time for which
information in that control message should be considered valid until
discarded, and the time until the next control message of the same
type should be expected [RFC5497].
4.6.1. Interval Time Attack
A use of the expected interval between two successive HELLO messages
is for determining the link quality in NHDP: if messages are not
received within the expected intervals (e.g., a certain fraction of
messages are missing), then this may be used to exclude a link from
being considered as useful, even if (some) bi-directional
communication has been verified. If a Compromised NHDP router X
spoofs the identity of an existing NHDP router A, and sends HELLOs
indicating a low interval time, an NHDP router B receiving this HELLO
will expect the following HELLO to arrive within the interval time
indicated - or otherwise, decrease the link quality for the link A-B.
Thus, X may cause NHDP router B's estimate of the link quality for
the link A-B to fall below the limit, where it is no longer
considered as useful and, thus, not used.
Herberg, et al. Expires September 21, 2013 [Page 8]
Internet-Draft Security Threats for NHDP March 2013
4.6.2. Validity Time Attack
A Compromised NHDP router X can spoof the identity of an NHDP router
A and send a HELLO using a low validity time (e.g.,1 ms). A
receiving NHDP router B will discard the information upon expiration
of that interval, i.e., a link between NHDP router A and B will be
"torn down" by X. It can be caused by intended malicious behaviors,
or simply mis-configuration in the NHDP routers.
4.7. Indirect Jamming
Indirect jamming is when a Compromised NHDP router X by its actions
causes other legitimate NHDP routers to generate inordinate amounts
of control traffic. This increases channel occupation, and the
overhead in each receiving NHDP router processing this control
traffic. With this traffic originating from Legitimate NHDP routers,
the malicious device may remain undetected to the wider network.
Figure 3 illustrates indirect jamming of NHDP. A Compromised NHDP
router X advertises a symmetric spoofed link to the non-existing NHDP
router B (at time t0). Router A selects X as MPR upon reception of
the HELLO, and will trigger a HELLO at t1. Overhearing this
triggered HELLO, the attacker sends another HELLO at t2, advertising
the link to B as lost, which leads to NHDP router A deselecting the
attacker as MPR, and another triggered message at t3. The cycle may
be repeated, alternating advertising the link X-B as LOST and SYM.
Herberg, et al. Expires September 21, 2013 [Page 9]
Internet-Draft Security Threats for NHDP March 2013
MPRs(X) MPRs()
.---. .---. .---. .---.
| A | | A | | A | | A |
'---' '---' '---' '---'
| | | |
| SYM(B) | | LOST(B) |
| | | |
.---. .---. .---. .---.
| X | | X | | X | | X |
'---' '---' '---' '---'
. .
. .
. .
..... .....
. B . . B .
..... .....
t0 t1 t2 t3
Figure 3
4.8. Attack on Link Quality Update
According to NHDP, "Link quality is a mechanism whereby a router MAY
take considerations other than message exchange into account for
determining when a link is and is not a candidate for being
considered as HEARD or SYMMETRIC. As such, it is a link admission
mechanism.".
Section 14.4 of NHDP [RFC6130] then lists several examples of which
information can be used to update link quality. One of the listed
examples is to update link quality based on [RFC5444] packet
exchanges between neighbor routers, e.g., an NHDP Router may update
the link quality of a neighbor based on receipt or loss of packets if
they include a sequential packet sequence number.
NHDP does not specify how to acquire link quality updates
normatively, however, attack vectors may be introduced if an
implementation chooses to calculate link quality based on packet
sequence numbers. The consequences of such threats would depend on
specific implementations. For example, if the link quality update is
based on sequential packet sequence number from neighbor routers, a
Comprised NDHP Router can spoof packets appearing to be from another
Legitimate NHDP Router that skips some packet sequence numbers. The
NHDP Router receiving the spoofed packets may degrade the link
quality as it appears that several packets have been dropped.
Eventually, the router remove the neighbor when the link quality
drops below HYST_REJECT.
Herberg, et al. Expires September 21, 2013 [Page 10]
Internet-Draft Security Threats for NHDP March 2013
5. Impact of inconsistent Information Bases on Protocols using NHDP
This section describes the impact on protocols, using NHDP, of NHDP
failing to obtain and represent accurate information, possibly as a
consequence of the attacks described in Section 4. This description
emphasizes the impacts on the MANET protocols OLSRv2 [OLSRv2], and
SMF [RFC6621].
5.1. MPR Calculation
MPR selection (as used in e.g., [OLSRv2] and [RFC6621]) uses
information about a router's 1-hop and 2-hop neighborhood, assuming
that (i) this information is accurate, and (ii) all 1-hop neighbors
are apt to act as as MPR, depending on the willingness they report.
Thus, a Compromised NHDP router will seek to manipulate the 1-hop and
2-hop neighborhood information in a router such as to cause the MPR
selection to fail, leading to a flooding disruption of TC messages.
5.1.1. Flooding Disruption due to Identity Spoofing
A Compromised NHDP router can spoof the identify of other routers, to
disrupt the MPR selection, so as to cache certain parts of the
network from the flooding traffic.
In Figure 4, a Compromised NHDP router X spoofs the identity of B.
The link between X and C is correctly detected and listed in X's
HELLOs. Router A will receive HELLOs indicating links from,
respectively B:{B-E}, X:{X-C, X-E}, and D:{D-E, D-C}. For router A,
X and D are equal candidates for MPR selection. To make sure the X
can be selected as MPR for router A, X can set its willingness to the
maximum value.
.---. .---. .---.
| E |----| D |----| C |
'---' '---' '---'
| | .
| | .
.---. .---. .---.
| B |----| A |----| X |
'---' '---' '---'
spoofs B
Figure 4
If B and X (i) accept MPR selection and (ii) forward flooded traffic
as-if they were both B, identity spoofing by X is harmless. However,
if X does not forward flooded traffic (i.e., does not accept MPR
selection), its presence entails flooding disruption: selecting B
Herberg, et al. Expires September 21, 2013 [Page 11]
Internet-Draft Security Threats for NHDP March 2013
over D renders C unreachable by flooded traffic.
.---.
| D |
'---'
|
|
.---. .---. .---. .---. .---.
| X |----| A |----| B |----| C |----| E |...
'---' '---' '---' '---' '---'
spoofs E
Figure 5
In Figure 5, the Compromised NHDP router X spoofs the identity of E,
i.e.,router A and C both receive HELLOs from a router identifying as
E. For router B, A and C present the same neighbor sets, and are
equal candidates for MPR selection. If router B selects only router
A as MPR, C will not relay flooded traffic from or transiting via B,
and router X (and routers to the "right" of it) will not receive
flooded traffic.
5.1.2. Flooding Disruption due to Link Spoofing
A Compromised NHDP router can also spoof links to other NHDP routers,
and thereby makes itself appear as the most appealing candidate of
MPR for its neighbors, possibly to the exclusion of other NHDP
routers in the neighborhood (this, in particular, if the Compromised
NHDP router spoof links to all other NHDP routers in the
neighborhood, plus to one other NHDP router). By thus excluding
other legitimate NHDP routers from being selected as MPR, the
Compromised NHDP router will receive and be expected to relay all
flooded traffic (e.g., TC messages in OLSRv2 or data traffic in SMF)
- which it can then drop or otherwise manipulate.
In the network in Figure 6, the Compromised NHDP router X spoofs
links to the existing router C, as well as to a fictitious W. Router
A receives HELLOs from X and B, reporting X: {X-C, X-W}, b: {B-C}.
All else being equal, X appears a better choice as MPR than B, as X
appears to cover all neighbors of B, plus W.
Herberg, et al. Expires September 21, 2013 [Page 12]
Internet-Draft Security Threats for NHDP March 2013
,---. .....
| S | . C .
'---' .....
| .
| .
.---. .---. .---. .---. .---.
| D |----| C |----| B |----| A |----| X |
'---' '---' '---' '---' '---'
.
.
.....
. w .
.....
Figure 6
As router A will not select B as MPR, B will not relay flooded
messages received from router A. The NHDP routers on the left of B
(starting with C) will, thus, not receive any flooded messages from
or transiting NHDP router A (e.g., a message originating from S).
5.1.3. Broadcast Storm
Compromised NHDP router may attack the network by attempting to
degrade the performance of optimized flooding algorithms so as to be
equivalent to classic flooding. This can be achieved by forcing an
NHDP router into choosing all its 1-hop neighbors as MPRs. In
MANETs, a broadcast storm caused by classic flooding is a serious
problem which can result in redundancy, contention and collisions
[broadcast-storm].
As shown in Figure 7, the Compromised NHDP router X spoofs the
identity of NHDP router B and, spoofs a link to router Y {B-Y} (Y
does not have to be exist). By doing so, the legitimate NHDP router
A has to select the legitimate NHDP router B as its MPR, in order for
it to reach all its 2-hop neighbors. The Compromised NHDP router Y
can perform this identity+link spoofing for all of NHDP router A's
1-hop neighbors, thereby forcing NHDP router A to select all its
neighbors as MPR - disabling the optimization sought by the MPR
mechanism.
Herberg, et al. Expires September 21, 2013 [Page 13]
Internet-Draft Security Threats for NHDP March 2013
.---.
| B |
'---'
|
|
.---. .---. .....
| A |----| X | . . . Y .
'---' '---' .....
spoofs B
Figure 7
5.2. Routing Loops
Inconsistent information bases, provided by NHDP to other protocols,
can also cause routing loops. In Figure 8, the Compromised NHDP
router X spoofs the identity of NHDP router E. NHDP router D has data
traffic to send to NHDP router A. The topology recorded in the
information base of router D indicates that the shortest path to
router A is {D->E->A}, because of the link {A-E} reported by X.
Therefore, the data traffic will be routed to the NHDP router E. As
the link {A-E} does not exist in NHDP router E's information bases,
it will identify the next hop for data traffic to NHDP router A as
being NHDP router D. A loop between the NHDP routers D and E is thus
created.
.---. .---. .---. .---. .---.
| A |----| B |----| C |----| D |----| E |
'---' '---' '---' '---' '---'
|
|
.---.
| X |
'---'
spoofs E
Figure 8
5.3. Invalid or Non-Existing Paths to Destinations
By reporting inconsistent topology information in NHDP, the invalid
links/routers can be propagated as link state information with TC
messages and results in route failure. As illustrated in Figure 8,
if NHDP router B tries to send data packets to NHDP router E, it will
choose router A as its next hop, based on the information of non-
existing link {A-E} reported by the Compromised NHDP router X.
Herberg, et al. Expires September 21, 2013 [Page 14]
Internet-Draft Security Threats for NHDP March 2013
5.4. Data Sinkhole
With the ability to spoof multiple identities of legitimate NHDP
routers (by eavesdropping, for example), the Compromised NHDP router
can represent a "data sinkhole" for its 1-hop and 2-hop neighbors.
Data packets that come across its neighbors may be forwarded to the
Compromised NHDP router instead of to the real destination. The
packet can then be dropped, manipulated, duplicated, etc., by the
Compromised NHDP router. As shown in Figure 8, if the Compromised
NHDP router X spoofs the identity of NHDP router E, all the data
packets to E that cross NHDP routers A and B will be sent to NHDP
router X, instead of to E.
6. Security Considerations
This document does not specify a protocol or a procedure. The
document, however, reflects on security considerations for NHDP and
MANET routing protocols using NHDP for neighborhood discovery.
7. IANA Considerations
This document contains no actions for IANA.
8. Acknowledgments
The authors would like to gratefully acknowledge the following people
for valuable comments and technical discussions: Teco Boot, Henning
Rogge, Christopher Dearlove, John Dowdell, and the all the other
participants of IETF MANET working group.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5444] Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
"Generalized MANET Packet/Message Format", RFC 5444,
February 2009.
[RFC5497] Clausen, T. and C. Dearlove, "Representing Multi-Value
Time in Mobile Ad Hoc Networks (MANETs)", RFC 5497,
March 2009.
Herberg, et al. Expires September 21, 2013 [Page 15]
Internet-Draft Security Threats for NHDP March 2013
[RFC6130] Clausen, T., Dean, J., and C. Dearlove, "MANET
Neighborhood Discovery Protocol (NHDP)", RFC 6130,
April 2011.
9.2. Informative References
[OLSRv2] Clausen, T., Dearlove, C., Philippe, P., and U. Herberg,
"The Optimized Link State Routing Protocol version 2",
work in progress draft-ietf-manet-olsrv2-18.txt,
March 2013.
[RFC6621] Macker, J., "Simplified Multicast Forwarding", RFC 6621,
March 2012.
[broadcast-storm]
Ni, S., Tseng, Y., Chen, Y., and J. Sheu, "The Broadcast
Storm Problem in a Mobile Ad Hoc Network", Proceedings of
the 5th annual ACM/IEEE international conference on Mobile
computing and networking, 1999.
Authors' Addresses
Ulrich Herberg
Fujitsu Laboratories of America
1240 E Arques Ave
Sunnyvale, CA 94085
USA
Email: ulrich@herberg.name
URI: http://www.herberg.name/
Jiazi Yi
LIX, Ecole Polytechnique
91128 Palaiseau Cedex,
France
Phone: +33 1 69 33 40 31
Email: jiazi@jiaziyi.com
URI: http://www.jiaziyi.com/
Herberg, et al. Expires September 21, 2013 [Page 16]
Internet-Draft Security Threats for NHDP March 2013
Thomas Heide Clausen
LIX, Ecole Polytechnique
91128 Palaiseau Cedex,
France
Phone: +33 6 6058 9349
Email: T.Clausen@computer.org
URI: http://www.thomasclausen.org/
Herberg, et al. Expires September 21, 2013 [Page 17]