Network Working Group A. Barbir
Internet-Draft Nortel Networks
Expires: October 12, 2004 S. Murphy
Sparta, Inc.
Y. Yang
Cisco Systems
April 13, 2004
Generic Threats to Routing Protocols
draft-ietf-rpsec-routing-threats-06
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Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
Routing protocols are subject to attacks that can harm individual
users or network operations as a whole. This document provides a
description and a summary of generic threats that affect routing
protocols in general. This work describes threats, including threat
sources and capabilities, threat actions, and threat consequences as
well as a breakdown of routing functions that might be separately
attacked.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Routing Functions Overview . . . . . . . . . . . . . . . . . . 4
3. Generic Routing Protocol Threat Model . . . . . . . . . . . . 5
3.1 Threat Definitions . . . . . . . . . . . . . . . . . . . . 5
3.1.1 Threat Sources . . . . . . . . . . . . . . . . . . . . 6
3.1.2 Threat Consequences . . . . . . . . . . . . . . . . . 6
4. Generally Identifiable Routing Threats . . . . . . . . . . . . 11
4.1 Deliberate Exposure . . . . . . . . . . . . . . . . . . . 11
4.2 Sniffing . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3 Traffic Analysis . . . . . . . . . . . . . . . . . . . . . 12
4.4 Spoofing . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5 Falsification . . . . . . . . . . . . . . . . . . . . . . 13
4.5.1 Falsifications by Originators . . . . . . . . . . . . 13
4.5.2 Falsifications by Forwarders . . . . . . . . . . . . . 16
4.6 Interference . . . . . . . . . . . . . . . . . . . . . . . 17
4.7 Overload . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8 Byzantine Failures . . . . . . . . . . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 19
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 Normative References . . . . . . . . . . . . . . . . . . . . 20
6.2 Informative References . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 20
A. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22
B. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Intellectual Property and Copyright Statements . . . . . . . . 24
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1. Introduction
Routing protocols are subject to threats and attacks that can harm
individual users or the network operations as a whole. The document
provides a summary of generic threats that affect routing protocols.
In particular, this work identifies generic threats to routing
protocols that include threat sources, threat actions, and threat
consequences. A breakdown of routing functions that might be
separately attacked is provided.
This work should be considered as a precursor to developing a common
set of security requirements for routing protocols. While it is well
known that bad, incomplete, or poor implementations of routing
protocols may, in themselves, lead to routing problems or failures,
or may increase the risk of a network being attacked successfully,
these issues are not considered here. This document only considers
attacks against robust, well considered implementations of routing
protocols, as outlined in OSPF [5], IS-IS [6], RIP [7] and BGP [8].
The document is organized as follows: Section 2 provides a review of
routing functions. Section 3 defines threats. In section 4, a
discussion on generally identifiable routing threat actions is
provided. Section 5 addresses security considerations.
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2. Routing Functions Overview
This section provides an overview of common functions that are shared
among various routing protocols. In general, routing protocols share
the following functions:
o Transport Subsystem: The routing protocol transmits messages to
its neighbors using some underlying protocol. For example, OSPF
uses IP, while other protocols may run over TCP.
o Neighbor State Maintenance: Neighboring relationship formation is
the first step for topology determination. For this reason,
routing protocols may need to maintain state information. Each
routing protocol may use a different mechanism for determining its
neighbors in the routing topology. Some protocols have distinct
exchanges through which they establish neighboring relationships,
e.g., Hello exchanges in OSPF.
o Database Maintenance: Routing protocols exchange network topology
and reachability information. The routers collect this information
in routing databases with varying detail. The maintenance of these
databases is a significant portion of the function of a routing
protocol.
In a routing protocol there are message exchanges that are intended
for the control of the state of the protocol. For example, neighbor
maintenance messages carry such information. On the other hand, there
are messages that are used to exchange information that is intended
to be used in the forwarding function. These messages effects the
data (information) part of the routing protocol. For example,
messages that are used to maintain the database.
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3. Generic Routing Protocol Threat Model
The model developed in this section can be used to identify threats
to any routing protocol. It examines attacks which can be launched
against routing from subverted entities within the routing system and
from entities outside the routing system. Both of these types of
entities are called unauthorized entities.
Routing protocols are subject to threats at various levels. For
example, an attacker may attack messages that carry control
information in a routing protocol to break a neighboring (e.g.,
peering, adjacency) relationship. This type of attack can impact the
network routing behavior in the affected routers and likely the
surrounding neighborhood. An attacker may attack messages that carry
data information to break a database exchange between two routers. An
attacker who is able to introduce bogus data can have a strong effect
on the behavior of routing in the neighborhood.
At the routing function level, threats can affect the transport
subsystem, where the routing protocol can be subject to attacks on
its underlying protocol. At the neighbor state maintenance level,
there are threats that can lead to attacks that can disrupt the
neighboring relationship with widespread consequences. For example,
in BGP, if a router receives a CEASE message, it can lead to breaking
its neighboring relationship to other routers.
There are threats against the database maintenance functionality. For
example, the information in the database must be authentic and
authorized. Threats that jeopardize this information can affect the
routing functionality in the overall network. For example, if an OSPF
router sends LSAs with the wrong Advertising Router, the receivers
will compute an SPF tree that is incorrect and might not forward the
traffic. If a BGP router advertises a NLRI that it is not authorized
to advertise, then receivers might forward that NLRI's traffic toward
that router and the traffic would not be deliverable. A PIM router
might transmit a JOIN message to receive multicast data it would
otherwise not receive.
3.1 Threat Definitions
In this work, a threat is defined as a motivated, capable adversary.
This characterization of threats clearly distinguishes threats from
attacks. By modeling the motivations (attack goals) and capabilities
of the adversaries who are threats, one can better understand what
classes of attacks these threats may mount and thus what types of
countermeasures will be required to deal with these attacks. In [1],
a threat is defined as a potential for violation of security, which
exists when there is a circumstance, capability, action, or event
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that could breach security and cause harm. Threats can be categorized
based on various rules, such as threat sources, threat actions,
threat consequences, threat consequence zones, and threat consequence
periods.
3.1.1 Threat Sources
There are many sources for threats that may affect routing protocols.
In some cases, unauthorized entities such as attackers may illegally
participate in the routing operations. In other circumstances, there
are threats to routing protocols from entities that are running
incorrect code, or using invalid configurations.
Threats can originate from outsiders or insiders. An insider is an
authorized participant in the routing protocol. An outsider is any
other host or network. A particular router determines if a host is an
outsider or an insider.
In general, threats can be classified into the following categories
based on their sources [2]:
o Threats that result from subverted links: A link becomes subverted
when an attacker gains access to (or control) it through a
physical medium. The attacker can then take control over the link.
This threat can result from the lack (or the use of weak) access
control mechanisms as applied to physical mediums or channels. The
attacker may eavesdrop, replay, delay, or drop routing messages,
or break routing sessions between authorized routers, without
participating in the routing exchange.
o Threats that result from subverted devices (e.g. routers): A
subverted device (router) is an authorized router that may have
been broken into by an attacker. The attacker can use the
subverted device to inappropriately claim authority for some
network resources, or violate routing protocols, such as
advertising invalid routing information.
3.1.2 Threat Consequences
A threat consequence is a security violation that results from a
threat action [1]. The compromise to the behavior of the routing
system can damage a particular network or host or can damage the
operation of the network as a whole.
There are four types of threat consequences: disclosure, deception,
disruption, and usurpation [1].
o Disclosure: Disclosure of routing information happens when a
router successfully accesses the information without being
authorized. Subverted links can cause disclosure, if routing
exchanges lack confidentiality. Subverted devices (routers), can
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cause disclosure, as long as they are successfully involved in the
routing exchanges. Although inappropriate disclosure of routing
information can pose a security threat or be part of a later,
larger, or higher layer attack, confidentiality is not generally a
design goal of routing protocols.
o Deception: This consequence happens when a legitimate router
receives a forged routing message and believes it to be authentic.
Subverted links and/or subverted devices (routers)can cause this
consequence if the receiving router lacks the ability to check
routing message integrity or origin authentication.
o Disruption: This consequence occurs when a legitimate router's
operation is being interrupted or prevented. Subverted links can
cause this by replaying, delaying, or dropping routing messages,
or breaking routing sessions between legitimate routers. Subverted
devices (routers) can cause this consequence by sending false
routing messages, interfering with normal routing exchanges, or
flooding unnecessary messages. (DoS is a common threat action
causing disruption.)
o Usurpation: This consequence happens when an attacker gains
control over a legitimate router's services/functions. Subverted
links can cause this by delaying or dropping routing exchanges, or
replaying out-dated routing information. Subverted routers can
cause this consequence by sending false routing information or
interfering routing exchanges.
Note: an attacker does not have to directly control a router to
control its services. For example, in Figure 1, Network 1 is
dual-homed through Router A and Router B, and Router A is preferred.
However, Router B is compromised and advertises a better metric.
Consequently, devices on the Internet choose the path through Router
B to reach Network 1. In this way, Router B steals the data traffic
and Router A surrenders its control of the services to Router B. This
depicted in Figure 1.
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+-------------+ +-------+
| Internet |---| Rtr A |
+------+------+ +---+---+
| |
| |
| |
| *-+-*
+-------+ / \
| Rtr B |----------* N 1 *
+-------+ \ /
*---*
Figure 1: Dual-homed Network
Several threat consequences might be caused by a single threat
action. In Figure 1, there exist at least two consequences: routers
using Router B to reach Network 1 are deceived, while Router A is
usurped.
Within the context of the threat consequences described above, damage
that might result from attacks against the network as a whole may
include:
o Network congestion: more data traffic is forwarded through some
portion of the network than would otherwise need to carry the
traffic,
o Blackhole: the consequence is that "packets go in, but go
nowhere",
o Looping: data traffic is forwarded along a route that loops, so
that the data is never delivered (resulting in network
congestion),
o Partition: some portion of the network believes that it is
partitioned from the rest of the network when it is not,
o Churn: the forwarding in the network changes (unnecessarily) at a
rapid pace, resulting in large variations in the data delivery
patterns (and adversely affecting congestion control techniques),
o Instability: the protocol becomes unstable so that convergence on
a global forwarding state is not achieved, and
o Overload: the protocol messages themselves become a significant
portion of the traffic the network carries.
The damage that might result from attacks against a particular host
or network address may include:
o Starvation: data traffic destined for the network or host is
forwarded to a part of the network that cannot deliver it,
o Eavesdrop: data traffic is forwarded through some router or
network that would otherwise not see the traffic, affording an
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opportunity to see the data or at least the data delivery pattern,
o Cut: some portion of the network believes that it has no route to
the host or network when it is in fact connected,
o Delay: data traffic destined for the network or host is forwarded
along a route that is in some way inferior to the route it would
otherwise take,
o Looping: data traffic for the network or host is forwarded along a
route that loops, so that the data is never delivered
It is important to consider all compromises, because some security
solutions can protect against one attack but not against others. It
might be possible to design a security solution that protects against
an attack that eavesdropped on one destination's traffic without
protecting against an attack that overwhelmed a router. Similarly, it
is possible to design a security solution that prevents a starvation
attack against one host, but not against a network wide resources.
The security requirements must be clear as to which compromises are
being avoided and which compromises must be addressed by other means
(e.g., by administrative means outside the protocol).
3.1.2.1 Threat Consequence Zone
A threat consequence zone covers the area within which the network
operations have been affected by threat actions. Possible threat
consequence zones can be classified as: a single link or router,
multiple routers (within a single routing domain), a single routing
domain, multiple routing domains, or the global Internet. The threat
consequence zone varies based on the threat action and origin.
Similar threat actions that happened at different locations may cause
totally different threat consequence. For example, when a compromised
link breaks the routing session between a distribution router and a
stub router, only reachability to and from the network devices
attached to the stub router will be impaired. In other words, the
threat consequence zone is a single router. In another case, if the
compromised router is located between a customer edge router and its
corresponding provider edge router, such an action might cause the
whole customer site to lose its connection. In this case, the threat
consequence zone might be a single routing domain.
3.1.2.2 Threat Consequence Periods
Threat consequence period is defined as a portion of time during
which the network operations are impacted by the threat consequences.
The threat consequence period is influenced by, but not totally
dependent on the duration of the threat action. In some cases, the
network operations will get back to normal as soon as the threat
action has been stopped. In other cases, however, threat consequences
may persist longer than the threat action. For example, in the
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original ARPANET link-state algorithm, some errors in a router
introduced three instances of an LSA. All of them flooded throughout
the network continuously, until the entire network was power cycled
[3].
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4. Generally Identifiable Routing Threats
This section addresses generally identifiable and recognized threat
actions against routing protocols. The threat actions are not
necessarily specific to individual protocols but may be present in
one or more of the common routing protocols in use today.
4.1 Deliberate Exposure
Deliberate Exposure occurs when an attacker takes control of a router
and intentionally releases routing information to other entities
(e.g., the attacker, a web page, mail posting, other routers etc. )
that, otherwise, should not receive the exposed information.
The consequence of deliberate exposure is the disclosure of routing
information.
The threat consequence zone of deliberate exposure depends on the
routing information that the attackers have exposed. The more
knowledge they have exposed, the bigger the threat consequence zone.
The threat consequence period of deliberate exposure might be longer
than the duration of the action itself. The routing information
exposed will not be out-dated until there is a topology change of the
exposed network.
4.2 Sniffing
Sniffing is an action whereby attackers monitor and/or record the
routing exchanges between authorized routers. Attackers can use
subverted links to sniff for routing information. Attackers can also
sniff data plane information (however, this is out of scope of the
current work).
The consequence of sniffing is disclosure of routing information.
The threat consequence zone of sniffing depends on the attacker's
location, the routing protocol type, and the routing information that
has been recorded. For example, if the subverted link is in an OSPF
totally stubby area, the threat consequence zone should be limited to
the whole area. An attacker that is sniffing a subverted link in an
EBGP session can gain knowledge of multiple routing domains.
The threat consequence period might be longer than the duration of
the action. If an attacker stops sniffing a subverted link their
acquired knowledge will not be out-dated until there is a topology
change of the affected network.
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4.3 Traffic Analysis
Traffic analysis is an action whereby attackers gain routing
information by analyzing the characteristics of the data traffic on a
subverted link. Traffic analysis threats can affect any data that is
sent over a communication link. This threat is not peculiar to
routing protocols and is included here for completeness.
The consequence of data traffic analysis is the disclosure of routing
information. For example, the source and destination IP addresses of
the data traffic, and the type, magnitude, and volume of traffic can
be disclosed.
The threat consequence zone of the traffic analysis depends on the
attacker's location and what data traffic has passed through. A
subverted link at the network core should be able to disclose more
information than its counterpart at the edge.
The threat consequence period might be longer than the duration of
the traffic analysis. After the attacker stops traffic analysis, its
knowledge will not be out-dated until there is a topology change of
the disclosed network.
4.4 Spoofing
Spoofing occurs when an illegitimate device assumes the identity of a
legitimate one. Spoofing in and of itself is often not the true
attack. Spoofing is special in that it can be used to carry out other
threat actions causing other threat consequences. An attacker can use
spoofing as a means for launching other types of attacks. For
example, if an attacker succeeds in spoofing the identity of a
router, the attacker can act as a masquerading router. In other
situations, the spoofing router can be used to send out unrealistic
routing information that might cause the disruption of network
services.
There are a few cases where spoofing can be an attack in and of
itself. For example, messages from an attacker which spoof the
identity of a legitimate router may cause a neighbor relationship to
form and deny the formation of the relationship with the legitimate
router.
The consequences of spoofing are:
o The disclosure of routing information: The spoofing router will be
able to gain access to the routing information.
o The deception of peer relationship: The authorized routers, which
exchange routing messages with the spoofing router, do not realize
they are neighboring with a router that is faking another router's
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identity.
The threat consequence zone covers:
o The consequence zone of the fake peer relationship will be limited
to those routers trusting the attacker's claimed identity.
o The consequence zone of the disclosed routing information depends
on the attacker's location, the routing protocol type, and the
routing information that has been exchanged between the attacker
and its deceived neighbors.
Note: This section focuses on addressing spoofing as a threat on its
own. However, spoofing creates conditions for other threats. Other
consequences are considered falsifications and are treated in the
next section.
4.5 Falsification
Falsification is an intentional action whereby false routing
information is sent by a subverted router. To falsify the routing
information, an attacker has to be either the originator or a
forwarder of the routing information. It cannot be a receiver-only.
False routing information describes the network in an unrealistic
fashion, whether or not intended by the authoritative network
administrator.
4.5.1 Falsifications by Originators
An originator of routing information can launch the falsifications
that are described in the next sections.
4.5.1.1 Overclaiming
Overclaiming occurs when a subverted router advertises its control of
some network resources, while in reality it does not, or the
advertisement is not authorized. This is given in Figure 2 and Figure
3.
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+-------------+ +-------+ +-------+
| Internet |---| Rtr B |---| Rtr A |
+------+------+ +-------+ +---+---+
| .
| |
| .
| *-+-*
+-------+ / \
| Rtr C |------------------* N 1 *
+-------+ \ /
*---*
Figure 2: Overclaiming-1
+-------------+ +-------+ +-------+
| Internet |---| Rtr B |---| Rtr A |
+------+------+ +-------+ +-------+
|
|
|
| *---*
+-------+ / \
| Rtr C |------------------* N 1 *
+-------+ \ /
*---*
Figure 3: Overclaiming-2
The above figures provide examples of overclaiming. Router A, the
attacker, is connected to the Internet through Router B. Router C is
authorized to advertise its link to Network 1. In Figure 2, Router A
controls a link to Network 1, but is not authorized to advertise it.
In Figure 3, Router A does not control such a link. But in either
case, Router A advertises the link to the Internet, through Router B.
Compromised routers, unauthorized routers, and masquerading routers
can overclaim network resources. The consequence of overclaiming
includes:
o Usurpation of the overclaimed network resources. In Figure 2 and
Figure 3, usurpation of Network 1 can occur when Router B (or
other routers on the Internet, (not shown in the figures))
believes that Router A provides the best path to reach the Network
1. As a result, routers forward data traffic, destined to Network
1 to Router A. The best result is that the data traffic uses an
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unauthorized path, as in Figure 2. The worst case is that the data
never reaches the destination Network 1, as in Figure 3. The
ultimate consequence is Router A gaining control over Network 1's
services, by controlling the data traffic.
o Usurpation of the legitimate advertising routers. In Figure 2 and
Figure 3 Router C is the legitimate advertiser of Network 1. By
overclaiming, Router A also controls (partially or totally) the
services/functions provided by the Router C. (This is NOT a
disruption, because Router C is operating in a way intended by the
authoritative network administrator.)
o Deception of other routers. In Figure 2 and Figure 3, Router B, or
other routers on the Internet, might be deceived to believe the
path through Router A is the best.
o Disruption of data planes on some routers. This might happen to
routers that are on the path that is used by other routers to each
the overclaimed network resources through the attacker. In Figure
2 and Figure 3, when other routers on the Internet are deceived,
they will forward the data traffic to Router B, which might be
overloaded.
The threat consequence zone varies based on the consequence:
o Where usurpation is concerned, the consequence zone covers the
network resources that are overclaimed by the attacker (Network 1
in Figure 2 and 3), and the routers that are authorized to
advertise the network resources but lose the competition against
the attacker(Router C in Figure 2 and Figure 3).
o Where deception is concerned, the consequence zone covers the
routers that do believe the attacker's advertisement and use the
attacker to reach the claimed networks (Router B and other
deceived routers on the Internet in Figure 2 and Figure 3).
o Where disruption is concerned, the consequence zone includes the
routers that are on the path of misdirected data traffic (Router B
in Figure 2 and Figure 3).
The threat consequence will cease when the attacker stops
overclaiming, and will totally disappear when the routing tables are
converged. As a result the consequence period is longer than the
duration of the overclaiming.
4.5.1.2 Misclaiming
A misclaiming threat is defined as an action where an attacker is
advertising its authorized control of some network resources in a way
that is not intended by the authoritative network administrator. An
attacker can eulogize or disparage when advertising these network
resources. Subverted routers, unauthorized routers, and masquerading
routers can misclaim network resources.
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The threat consequences of misclaiming are similar to the
consequences of overclaiming.
The consequence zone and period are also similar to those of
overclaiming.
4.5.2 Falsifications by Forwarders
When a legitimate router forwards routing information, it must or
must not modify the routing information, depending on the routing
information and the routing protocol type. For example, in RIP, the
forwarder must modify the routing information by increasing the hop
count by 1. On the other hand, the forwarder must not modify the type
1 LSA in OSPF. In general, forwarders in distance vector routing
protocols are authorized to and must modify the routing information,
while most forwarders in link state routing protocols are not
authorized to and must not modify most routing information.
As a forwarder authorized to modify routing message, an attacker
might not forward necessary routing information to other authorized
routers.
4.5.2.1 Misstatement
This is defined as an action whereby the attacker describes route
attributes in an incorrect manner. For example, in RIP, the attacker
might increase the path cost by two hops instead of one. In BGP, the
attacker might delete some AS numbers from the AS PATH.
Where forwarding routing information should not be modified, an
attacker can launch the following falsifications:
o Deletion: Attacker deletes valid data in the routing message.
o Insertion: Attacker inserts false data in the routing message.
o Substitution: Attacker replaces valid data in the routing message
with false data.
o Replaying: Attacker replays out-dated data in the routing message.
All types of attackers (compromised links, compromised routers,
unauthorized routers, and masquerading routers) can falsify the
routing information when they forward the routing messages.
The threat consequences of these falsifications by forwarders are
similar to those caused by originators: usurpation of some network
resources and related routers; deception of routers using false
paths; and disruption of data planes of routers on the false paths.
The threat consequence zone and period are also similar.
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4.6 Interference
Interference is a threat action where an attacker uses a subverted
link or router to inhibit the exchanges by legitimate routers. The
attacker can do this by adding noise, or by not forwarding packets,
or by replaying out-dated packets, or by delaying responses, or by
denial of receipts, or by breaking synchronization.
Subverted, unauthorized and masquerading routers can slow down their
routing exchanges or induce flapping in the routing sessions of
legitimate neighboring routers.
The consequence of interference is the disruption of routing
operations.
The consequence zone of interference varies based on the source of
the threats:
o When a subverted link is used to launch the action, the threat
consequence zone covers routers that are using the link to
exchange the routing information. An attack on a link can cause
consequences at the neighbor maintenance level that may lead to
changes in the database. In this case, the consequences can be
felt network-wide.
o When subverted routers, unauthorized routers, or masquerading
routers are the attackers, the threat consequence zone covers
routers with which the attackers are exchanging routing
information.
The threat consequences might disappear as soon as the interference
is stopped, or might not totally disappear until the networks have
converged. Therefore, the consequence period is equal or longer than
the duration of the interference.
4.7 Overload
Overload is defined as a threat action whereby attackers place excess
burden on legitimate routers. For example, it is possible for an
attacker to trigger a router to create an excessive amount of state
that other routers within the network are not able to handle. In a
similar fashion, it is possible for an attacker to overload database
routing exchanges and thus influence the routing operations.
4.8 Byzantine Failures
As described in [4], "A node with a Byzantine failure may corrupt
messages, forge messages, delay messages, or send conflicting
messages to different nodes". These faults may arise from routers
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which have been subverted by an attacker or which have faulty
hardware or software. In any case, they represent a threat to correct
operation of routing and routing protocols.
The ability of the network to function in the face of such defects is
described as Byzantine robustness and would fall into the scope of a
requirements document for routing protocol security which may build
from the base established in this document.
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5. Security Considerations
This entire document is security related. Specifically the document
addresses security of routing protocols as associated with threats to
those protocols. In a larger context, this work builds upon the
recognition of the IETF community that signaling and control/
management planes of networked devices need strengthening. Routing
protocols can be considered part of that signaling and control plane.
However, to date, routing protocols have largely remained unprotected
and open to malicious attacks. This document discusses inter- and
intra-domain routing protocol threats that are currently known and
lays the foundation for other documents that will discuss security
requirements for routing protocols. This document is protocol
independent.
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6. References
6.1 Normative References
[1] Shirey, R, "Internet Security Glossary", RFC 2828 , May 2000.
[2] Smith, B et al., "Securing Distance-Vector Routing Protocols",
Symposium on Network and Distributed System Security , February
1997.
[3] Rosen, E., "Vulnerabilities of Network Control Protocols: An
Example, Computer Communication Review", , July 1981.
[4] Perlman, R, "Network Layer Protocols with Byzantine Robustness",
, August 1988 .
[5] Moy, J, "OSPF Version 2", RFC 2328, April 1998.
[6] Shen, N. et. al., "Dynamic Hostname Exchange Mechanism for
IS-IS", RFC 2763 , February 2000.
[7] Malkin, G., "RIP Version 2 Protocol Analysis", RFC 1721 ,
November 1994.
6.2 Informative References
[8] Kent, S. et al., "Secure Border Gateway Protocol
(Secure-BGP)", IEEE Journal on Selected Areas in Communications
, April 2000.
Authors' Addresses
Abbie Barbir
Nortel Networks
3500 Carling Avenue
Nepean, Ontario K2H 8E9
Canada
Phone:
EMail: abbieb@nortelnetworks.com
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Sandy Murphy
Sparta, Inc.
7075 Samuel Morse Drive
Columbia, MD
USA
Phone: 410-872-1515 x206
EMail: sandy@tislabs.com
Yi Yang
Cisco Systems
7025 Kit Creek Road
RTP, NC 27709
USA
Phone:
EMail: yiya@cisco.com
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Appendix A. Acknowledgments
This draft would not have been possible save for the excellent
efforts and team work characteristics of those listed here.
o Dennis Beard- Nortel Networks
o Ayman Musharbash - Nortel Networks
o Jean-Jacques Puig, int-evry, France
o Paul Knight - Nortel Networks
o Elwyn Davies - Nortel Networks
o Ameya Dilip Pandit - Graduate student - University of Missouri
o Senthilkumar Ayyasamy - Graduate student - University of Missouri
o Stephen Kent- BBN
o Tim Gage - CISCO
o James Ng - CISCO
o Alvaro Retana - CISCO
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Appendix B. Acronyms
AS - Autonomous system. Set of routers under a single technical
administration. Each AS normally uses a single interior gateway
protocol (IGP) and metrics to propagate routing information within
the set of routers. Also called routing domain.
AS-Path - In BGP, the route to a destination. The path consists of
the AS numbers of all routers a packet must go through to reach a
destination.
BGP - Border Gateway Protocol. Exterior gateway protocol used to
exchange routing information among routers in different autonomous
systems.
LSA - Link-State Announcement
NLRI - Network layer reachability information. Information that is
carried in BGP packets and is used by MBGP.
OSPF - Open Shortest Path First. A link-state IGP that makes routing
decisions based on the shortest-path-first (SPF) algorithm (also
referred to as the Dijkstra algorithm).
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