draft-ietf-detnet-security-06.txt   draft-ietf-detnet-security-07.txt 
Internet Engineering Task Force T. Mizrahi Internet Engineering Task Force T. Mizrahi
Internet-Draft HUAWEI Internet-Draft HUAWEI
Intended status: Informational E. Grossman, Ed. Intended status: Informational E. Grossman, Ed.
Expires: May 4, 2020 DOLBY Expires: July 13, 2020 DOLBY
A. Hacker A. Hacker
MISTIQ MISTIQ
S. Das S. Das
Applied Communication Sciences Applied Communication Sciences
J. Dowdell J. Dowdell
Airbus Defence and Space Airbus Defence and Space
H. Austad H. Austad
SINTEF Digital SINTEF Digital
N. Finn N. Finn
HUAWEI HUAWEI
November 1, 2019 January 10, 2020
Deterministic Networking (DetNet) Security Considerations Deterministic Networking (DetNet) Security Considerations
draft-ietf-detnet-security-06 draft-ietf-detnet-security-07
Abstract Abstract
A deterministic network is one that can carry data flows for real- A deterministic network is one that can carry data flows for real-
time applications with extremely low data loss rates and bounded time applications with extremely low data loss rates and bounded
latency. Deterministic networks have been successfully deployed in latency. Deterministic networks have been successfully deployed in
real-time operational technology (OT) applications for some years. real-time operational technology (OT) applications for some years.
However, such networks are typically isolated from external access, However, such networks are typically isolated from external access,
and thus the security threat from external attackers is low. IETF and thus the security threat from external attackers is low. IETF
Deterministic Networking (DetNet) specifies a set of technologies Deterministic Networking (DetNet) specifies a set of technologies
that enable creation of deterministic networks on IP-based networks that enable creation of deterministic networks on IP-based networks
of potentially wide area (on the scale of a corporate network) of potentially wide area (on the scale of a corporate network)
potentially bringing the OT network into contact with Information potentially bringing the OT network into contact with Information
Technology (IT) traffic and security threats that lie outside of a Technology (IT) traffic and security threats that lie outside of a
tightly controlled and bounded area (such as the internals of an tightly controlled and bounded area (such as the internals of an
aircraft). These DetNet technologies have not previously been aircraft). These DetNet technologies have not previously been
deployed together on a wide area IP-based network, and thus can deployed together on a wide area IP-based network, and thus can
present security considerations that may be new to IP-based wide area present security considerations that may be new to IP-based wide area
network designers. This draft, intended for use by DetNet network network designers. This document, intended for use by DetNet network
designers, provides insight into these security considerations. In designers, provides insight into these security considerations.
addition, this draft collects all security-related statements from
the various DetNet drafts (Architecture, Use Cases, etc) into a
single location Section 8.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 4, 2020. This Internet-Draft will expire on July 13, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 2, line 43 skipping to change at page 2, line 40
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Security Threats . . . . . . . . . . . . . . . . . . . . . . 6 3. Security Threats . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 7 3.2. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 7
3.2.1. Delay . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2.1. Delay . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.1.1. Delay Attack . . . . . . . . . . . . . . . . . . 7 3.2.1.1. Delay Attack . . . . . . . . . . . . . . . . . . 7
3.2.2. DetNet Flow Modification or Spoofing . . . . . . . . 7 3.2.2. DetNet Flow Modification or Spoofing . . . . . . . . 7
3.2.3. Resource Segmentation or Slicing . . . . . . . . . . 7 3.2.3. Resource Segmentation or Slicing . . . . . . . . . . 7
3.2.3.1. Inter-segment Attack . . . . . . . . . . . . . . 8 3.2.3.1. Inter-segment Attack . . . . . . . . . . . . . . 7
3.2.4. Packet Replication and Elimination . . . . . . . . . 8 3.2.4. Packet Replication and Elimination . . . . . . . . . 8
3.2.4.1. Replication: Increased Attack Surface . . . . . . 8 3.2.4.1. Replication: Increased Attack Surface . . . . . . 8
3.2.4.2. Replication-related Header Manipulation . . . . . 8 3.2.4.2. Replication-related Header Manipulation . . . . . 8
3.2.5. Path Choice . . . . . . . . . . . . . . . . . . . . . 9 3.2.5. Path Choice . . . . . . . . . . . . . . . . . . . . . 8
3.2.5.1. Path Manipulation . . . . . . . . . . . . . . . . 9 3.2.5.1. Path Manipulation . . . . . . . . . . . . . . . . 8
3.2.5.2. Path Choice: Increased Attack Surface . . . . . . 9 3.2.5.2. Path Choice: Increased Attack Surface . . . . . . 9
3.2.6. Control Plane . . . . . . . . . . . . . . . . . . . . 9 3.2.6. Control Plane . . . . . . . . . . . . . . . . . . . . 9
3.2.6.1. Control or Signaling Packet Modification . . . . 9 3.2.6.1. Control or Signaling Packet Modification . . . . 9
3.2.6.2. Control or Signaling Packet Injection . . . . . . 9 3.2.6.2. Control or Signaling Packet Injection . . . . . . 9
3.2.7. Scheduling or Shaping . . . . . . . . . . . . . . . . 9 3.2.7. Scheduling or Shaping . . . . . . . . . . . . . . . . 9
3.2.7.1. Reconnaissance . . . . . . . . . . . . . . . . . 9 3.2.7.1. Reconnaissance . . . . . . . . . . . . . . . . . 9
3.2.8. Time Synchronization Mechanisms . . . . . . . . . . . 9 3.2.8. Time Synchronization Mechanisms . . . . . . . . . . . 9
3.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 10 3.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 9
4. Security Threat Impacts . . . . . . . . . . . . . . . . . . . 10 4. Security Threat Impacts . . . . . . . . . . . . . . . . . . . 10
4.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 13 4.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 13
4.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 13 4.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 13
4.1.2. Control Plane Delay Attacks . . . . . . . . . . . . . 14 4.1.2. Control Plane Delay Attacks . . . . . . . . . . . . . 13
4.2. Flow Modification and Spoofing . . . . . . . . . . . . . 14 4.2. Flow Modification and Spoofing . . . . . . . . . . . . . 14
4.2.1. Flow Modification . . . . . . . . . . . . . . . . . . 14 4.2.1. Flow Modification . . . . . . . . . . . . . . . . . . 14
4.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 14 4.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 14
4.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 14 4.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 14
4.2.2.2. Control Plane Spoofing . . . . . . . . . . . . . 14 4.2.2.2. Control Plane Spoofing . . . . . . . . . . . . . 14
4.3. Segmentation attacks (injection) . . . . . . . . . . . . 15 4.3. Segmentation attacks (injection) . . . . . . . . . . . . 15
4.3.1. Data Plane Segmentation . . . . . . . . . . . . . . . 15 4.3.1. Data Plane Segmentation . . . . . . . . . . . . . . . 15
4.3.2. Control Plane segmentation . . . . . . . . . . . . . 15 4.3.2. Control Plane segmentation . . . . . . . . . . . . . 15
4.4. Replication and Elimination . . . . . . . . . . . . . . . 15 4.4. Replication and Elimination . . . . . . . . . . . . . . . 15
4.4.1. Increased Attack Surface . . . . . . . . . . . . . . 16 4.4.1. Increased Attack Surface . . . . . . . . . . . . . . 15
4.4.2. Header Manipulation at Elimination Bridges . . . . . 16 4.4.2. Header Manipulation at Elimination Bridges . . . . . 16
4.5. Control or Signaling Packet Modification . . . . . . . . 16 4.5. Control or Signaling Packet Modification . . . . . . . . 16
4.6. Control or Signaling Packet Injection . . . . . . . . . . 16 4.6. Control or Signaling Packet Injection . . . . . . . . . . 16
4.7. Reconnaissance . . . . . . . . . . . . . . . . . . . . . 16 4.7. Reconnaissance . . . . . . . . . . . . . . . . . . . . . 16
4.8. Attacks on Time Sync Mechanisms . . . . . . . . . . . . . 16 4.8. Attacks on Time Sync Mechanisms . . . . . . . . . . . . . 16
4.9. Attacks on Path Choice . . . . . . . . . . . . . . . . . 16 4.9. Attacks on Path Choice . . . . . . . . . . . . . . . . . 16
5. Security Threat Mitigation . . . . . . . . . . . . . . . . . 16 5. Security Threat Mitigation . . . . . . . . . . . . . . . . . 17
5.1. Path Redundancy . . . . . . . . . . . . . . . . . . . . . 17 5.1. Path Redundancy . . . . . . . . . . . . . . . . . . . . . 17
5.2. Integrity Protection . . . . . . . . . . . . . . . . . . 17 5.2. Integrity Protection . . . . . . . . . . . . . . . . . . 17
5.3. DetNet Node Authentication . . . . . . . . . . . . . . . 18 5.3. DetNet Node Authentication . . . . . . . . . . . . . . . 18
5.4. Dummy Traffic Insertion . . . . . . . . . . . . . . . . . 18 5.4. Dummy Traffic Insertion . . . . . . . . . . . . . . . . . 18
5.5. Encryption . . . . . . . . . . . . . . . . . . . . . . . 18 5.5. Encryption . . . . . . . . . . . . . . . . . . . . . . . 18
5.5.1. Encryption Considerations for DetNet . . . . . . . . 19 5.5.1. Encryption Considerations for DetNet . . . . . . . . 19
5.6. Control and Signaling Message Protection . . . . . . . . 20 5.6. Control and Signaling Message Protection . . . . . . . . 20
5.7. Dynamic Performance Analytics . . . . . . . . . . . . . . 20 5.7. Dynamic Performance Analytics . . . . . . . . . . . . . . 20
5.8. Mitigation Summary . . . . . . . . . . . . . . . . . . . 21 5.8. Mitigation Summary . . . . . . . . . . . . . . . . . . . 21
6. Association of Attacks to Use Cases . . . . . . . . . . . . . 22 6. Association of Attacks to Use Cases . . . . . . . . . . . . . 22
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6.1.19. Low Latency . . . . . . . . . . . . . . . . . . . . . 29 6.1.19. Low Latency . . . . . . . . . . . . . . . . . . . . . 29
6.1.20. Bounded Jitter (Latency Variation) . . . . . . . . . 29 6.1.20. Bounded Jitter (Latency Variation) . . . . . . . . . 29
6.1.21. Symmetrical Path Delays . . . . . . . . . . . . . . . 29 6.1.21. Symmetrical Path Delays . . . . . . . . . . . . . . . 29
6.1.22. Reliability and Availability . . . . . . . . . . . . 30 6.1.22. Reliability and Availability . . . . . . . . . . . . 30
6.1.23. Redundant Paths . . . . . . . . . . . . . . . . . . . 30 6.1.23. Redundant Paths . . . . . . . . . . . . . . . . . . . 30
6.1.24. Security Measures . . . . . . . . . . . . . . . . . . 30 6.1.24. Security Measures . . . . . . . . . . . . . . . . . . 30
6.2. Attack Types by Use Case Common Theme . . . . . . . . . . 31 6.2. Attack Types by Use Case Common Theme . . . . . . . . . . 31
6.3. Security Considerations for OAM Traffic . . . . . . . . . 33 6.3. Security Considerations for OAM Traffic . . . . . . . . . 33
7. DetNet Technology-Specific Threats . . . . . . . . . . . . . 33 7. DetNet Technology-Specific Threats . . . . . . . . . . . . . 33
7.1. IP . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.1. IP . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.2. MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.2. MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.3. TSN . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
8. Appendix A: DetNet Draft Security-Related Statements . . . . 35 9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
8.1. Architecture (draft 8) . . . . . . . . . . . . . . . . . 35 10. Informative References . . . . . . . . . . . . . . . . . . . 36
8.1.1. Fault Mitigation (sec 4.5) . . . . . . . . . . . . . 35 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38
8.1.2. Security Considerations (sec 7) . . . . . . . . . . . 36
8.2. Data Plane Alternatives (draft 4) . . . . . . . . . . . . 36
8.2.1. Security Considerations (sec 7) . . . . . . . . . . . 36
8.3. Problem Statement (draft 5) . . . . . . . . . . . . . . . 37
8.3.1. Security Considerations (sec 5) . . . . . . . . . . . 37
8.4. Use Cases (draft 11) . . . . . . . . . . . . . . . . . . 37
8.4.1. (Utility Networks) Security Current Practices and
Limitations (sec 3.2.1) . . . . . . . . . . . . . . . 37
8.4.2. (Utility Networks) Security Trends in Utility
Networks (sec 3.3.3) . . . . . . . . . . . . . . . . 39
8.4.3. (BAS) Security Considerations (sec 4.2.4) . . . . . . 41
8.4.4. (6TiSCH) Security Considerations (sec 5.3.3) . . . . 41
8.4.5. (Cellular radio) Security Considerations (sec 6.1.5) 41
8.4.6. (Industrial M2M) Communication Today (sec 7.2) . . . 42
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42
10. Security Considerations . . . . . . . . . . . . . . . . . . . 42
11. Informative References . . . . . . . . . . . . . . . . . . . 42
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
1. Introduction 1. Introduction
Security is of particularly high importance in DetNet networks Security is of particularly high importance in DetNet networks
because many of the use cases which are enabled by DetNet [RFC8578] because many of the use cases which are enabled by DetNet [RFC8578]
include control of physical devices (power grid components, include control of physical devices (power grid components,
industrial controls, building controls) which can have high industrial controls, building controls) which can have high
operational costs for failure, and present potentially attractive operational costs for failure, and present potentially attractive
targets for cyber-attackers. targets for cyber-attackers.
This situation is even more acute given that one of the goals of This situation is even more acute given that one of the goals of
DetNet is to provide a "converged network", i.e. one that includes DetNet is to provide a "converged network", i.e. one that includes
both IT traffic and OT traffic, thus exposing potentially sensitive both IT traffic and OT traffic, thus exposing potentially sensitive
OT devices to attack in ways that were not previously common (usually OT devices to attack in ways that were not previously common (usually
because they were under a separate control system or otherwise because they were under a separate control system or otherwise
isolated from the IT network, for example [ARINC664P7]). Security isolated from the IT network, for example [ARINC664P7]). Security
considerations for OT networks is not a new area, and there are many considerations for OT networks are not a new area, and there are many
OT networks today that are connected to wide area networks or the OT networks today that are connected to wide area networks or the
Internet; this draft focuses on the issues that are specific to the Internet; this document focuses on the issues that are specific to
DetNet technologies and use cases. the DetNet technologies and use cases.
Given the above considerations, securing a DetNet starts with a
scrupulously well-designed and well-managed engineered network
following industry best practices for security at both the data plane
and control plane; this is the assumed starting point for the
considerations discussed herein. In this context we view the network
design and managment aspects of network security as being primarily
concerned with denial-of service prevention by ensuring that DetNet
traffic goes where it's supposed to and that an external attacker
can't inject traffic that disrupts the DetNet's delivery timing
assurance. The time-specific aspects of DetNet security presented
here take up where the design and management aspects leave off.
The security requirements for any given DetNet network are
necessarily specific to the use cases handled by that network. Thus
the reader is assumed to be familiar with the specific security
requirements of their use cases, for example those outlined in the
DetNet Use Cases [RFC8578] and the Security Considerations sections
of the DetNet documents applicable to the network technologies in
use, for example [I-D.ietf-detnet-ip]).
The DetNet technologies include ways to: The DetNet technologies include ways to:
o Reserve data plane resources for DetNet flows in some or all of o Reserve data plane resources for DetNet flows in some or all of
the intermediate nodes (e.g. bridges or routers) along the path of the intermediate nodes (e.g. bridges or routers) along the path of
the flow the flow
o Provide explicit routes for DetNet flows that do not rapidly o Provide explicit routes for DetNet flows that do not rapidly
change with the network topology change with the network topology
o Distribute data from DetNet flow packets over time and/or space to o Distribute data from DetNet flow packets over time and/or space to
ensure delivery of each packet's data' in spite of the loss of a ensure delivery of each packet's data' in spite of the loss of a
path path
This draft includes sections on threat modeling and analysis, threat This document includes sections on threat modeling and analysis,
impact and mitigation, and the association of attacks with use cases threat impact and mitigation, and the association of attacks with use
based on the Use Case Common Themes section of the DetNet Use Cases cases based on the Use Case Common Themes section of the DetNet Use
draft [RFC8578]. Cases [RFC8578].
This draft also provides context for the DetNet security
considerations by collecting into one place Section 8 the various
remarks about security from the various DetNet drafts (Use Cases,
Architecture, etc). This text is duplicated here primarily because
the DetNet working group has elected not to produce a Requirements
draft and thus collectively these statements are as close as we have
to "DetNet Security Requirements".
2. Abbreviations 2. Abbreviations
IT Information technology (the application of computers to IT Information technology (the application of computers to
store, study, retrieve, transmit, and manipulate data or information, store, study, retrieve, transmit, and manipulate data or information,
often in the context of a business or other enterprise - Wikipedia). often in the context of a business or other enterprise - Wikipedia).
OT Operational Technology (the hardware and software OT Operational Technology (the hardware and software
dedicated to detecting or causing changes in physical processes dedicated to detecting or causing changes in physical processes
through direct monitoring and/or control of physical devices such as through direct monitoring and/or control of physical devices such as
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authenticated traffic. authenticated traffic.
o Man in the Middle (MITM) vs. packet injector: MITM attackers are o Man in the Middle (MITM) vs. packet injector: MITM attackers are
located in a position that allows interception and modification of located in a position that allows interception and modification of
in-flight protocol packets, whereas a traffic injector can only in-flight protocol packets, whereas a traffic injector can only
attack by generating protocol packets. attack by generating protocol packets.
Care has also been taken to adhere to Section 5 of [RFC3552], both Care has also been taken to adhere to Section 5 of [RFC3552], both
with respect to which attacks are considered out-of-scope for this with respect to which attacks are considered out-of-scope for this
document, but also which are considered to be the most common threats document, but also which are considered to be the most common threats
(explored furhter in Section 3.2. Most of the direct threats to (explored further in Section 3.2. Most of the direct threats to
DetNet are Active attacks, but it is highly suggested that DetNet DetNet are Active attacks, but it is highly suggested that DetNet
application developers take appropriate measures to protect the application developers take appropriate measures to protect the
content of the streams from passive attacks. content of the streams from passive attacks.
DetNet-Service, one of the service scenarios described in DetNet-Service, one of the service scenarios described in
[I-D.varga-detnet-service-model], is the case where a service [I-D.varga-detnet-service-model], is the case where a service
connects DetNet networking islands, i.e. two or more otherwise connects DetNet networking islands, i.e. two or more otherwise
independent DetNet network domains are connected via a link that is independent DetNet network domains are connected via a link that is
not intrinsically part of either network. This implies that there not intrinsically part of either network. This implies that there
could be DetNet traffic flowing over a non-DetNet link, which may could be DetNet traffic flowing over a non-DetNet link, which may
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3.2. Threat Analysis 3.2. Threat Analysis
3.2.1. Delay 3.2.1. Delay
3.2.1.1. Delay Attack 3.2.1.1. Delay Attack
An attacker can maliciously delay DetNet data flow traffic. By An attacker can maliciously delay DetNet data flow traffic. By
delaying the traffic, the attacker can compromise the service of delaying the traffic, the attacker can compromise the service of
applications that are sensitive to high delays or to high delay applications that are sensitive to high delays or to high delay
variation. variation. The delay may be constant or modulated.
3.2.2. DetNet Flow Modification or Spoofing 3.2.2. DetNet Flow Modification or Spoofing
An attacker can modify some header fields of en route packets in a An attacker can modify some header fields of en route packets in a
way that causes the DetNet flow identification mechanisms to way that causes the DetNet flow identification mechanisms to
misclassify the flow. Alternatively, the attacker can inject traffic misclassify the flow. Alternatively, the attacker can inject traffic
that is tailored to appear as if it belongs to a legitimate DetNet that is tailored to appear as if it belongs to a legitimate DetNet
flow. The potential consequence is that the DetNet flow resource flow. The potential consequence is that the DetNet flow resource
allocation cannot guarantee the performance that is expected when the allocation cannot guarantee the performance that is expected when the
flow identification works correctly. flow identification works correctly.
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A passive eavesdropper can identify DetNet flows and then gather A passive eavesdropper can identify DetNet flows and then gather
information about en route DetNet flows, e.g., the number of DetNet information about en route DetNet flows, e.g., the number of DetNet
flows, their bandwidths, their schedules, or other temporal flows, their bandwidths, their schedules, or other temporal
properties. The gathered information can later be used to invoke properties. The gathered information can later be used to invoke
other attacks on some or all of the flows. other attacks on some or all of the flows.
Note that in some cases DetNet flows may be identified based on an Note that in some cases DetNet flows may be identified based on an
explicit DetNet header, but in some cases the flow identification may explicit DetNet header, but in some cases the flow identification may
be based on fields from the L3/L4 headers. If L3/L4 headers are be based on fields from the L3/L4 headers. If L3/L4 headers are
involved, for purposes of this draft we assume they are encrypted involved, for purposes of this document we assume they are encrypted
and/or integrity-protected from external attackers. and/or integrity-protected from external attackers.
3.2.8. Time Synchronization Mechanisms 3.2.8. Time Synchronization Mechanisms
An attacker can use any of the attacks described in [RFC7384] to An attacker can use any of the attacks described in [RFC7384] to
attack the synchronization protocol, thus affecting the DetNet attack the synchronization protocol, thus affecting the DetNet
service. service.
3.3. Threat Summary 3.3. Threat Summary
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under the assumption that a corresponding security mechanism is being under the assumption that a corresponding security mechanism is being
used, and that the corresponding network equipment takes part in this used, and that the corresponding network equipment takes part in this
mechanism. mechanism.
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
| Attack | Attacker Type | | Attack | Attacker Type |
| +---------+---------+ | +---------+---------+
| |Internal |External | | |Internal |External |
| |MITM|Inj.|MITM|Inj.| | |MITM|Inj.|MITM|Inj.|
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|Delay attack | + | | + | | |Delay attack | + | + | + | + |
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|DetNet Flow Modification or Spoofing | + | + | | | |DetNet Flow Modification or Spoofing | + | + | | |
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|Inter-segment Attack | + | + | | | |Inter-segment Attack | + | + | | |
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|Replication: Increased Attack Surface | + | + | + | + | |Replication: Increased Attack Surface | + | + | + | + |
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|Replication-related Header Manipulation | + | | | | |Replication-related Header Manipulation | + | | | |
+-----------------------------------------+----+----+----+----+ +-----------------------------------------+----+----+----+----+
|Path Manipulation | + | + | | | |Path Manipulation | + | + | | |
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information. information.
DetNet raises these stakes significantly for OT applications, DetNet raises these stakes significantly for OT applications,
particularly those which may have been designed to run in an OT-only particularly those which may have been designed to run in an OT-only
environment and thus may not have been designed for security in an IT environment and thus may not have been designed for security in an IT
environment with its associated devices, services and protocols. environment with its associated devices, services and protocols.
The severity of various components of the impact of a successful The severity of various components of the impact of a successful
vulnerability exploit to use cases by industry is available in more vulnerability exploit to use cases by industry is available in more
detail in [RFC8578]. Each of the use cases in the DetNet Use Cases detail in [RFC8578]. Each of the use cases in the DetNet Use Cases
draft is represented in the table below, including Pro Audio, is represented in the table below, including Pro Audio, Electrical
Electrical Utilities, Industrial M2M (split into two areas, M2M Data Utilities, Industrial M2M (split into two areas, M2M Data Gathering
Gathering and M2M Control Loop), and others. and M2M Control Loop), and others.
Components of Impact (left column) include Criticality of Failure, Components of Impact (left column) include Criticality of Failure,
Effects of Failure, Recovery, and DetNet Functional Dependence. Effects of Failure, Recovery, and DetNet Functional Dependence.
Criticality of failure summarizes the seriousness of the impact. The Criticality of failure summarizes the seriousness of the impact. The
impact of a resulting failure can affect many different metrics that impact of a resulting failure can affect many different metrics that
vary greatly in scope and severity. In order to reduce the number of vary greatly in scope and severity. In order to reduce the number of
variables, only the following were included: Financial, Health and variables, only the following were included: Financial, Health and
Safety, People well being (People WB), Affect on a single Safety, People well being (People WB), Affect on a single
organization, and affect on multiple organizations. Recovery organization, and affect on multiple organizations. Recovery
outlines how long it would take for an affected use case to get back outlines how long it would take for an affected use case to get back
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Figure 2: Impact of Attacks by Use Case Industry Figure 2: Impact of Attacks by Use Case Industry
The rest of this section will cover impact of the different groups in The rest of this section will cover impact of the different groups in
more detail. more detail.
4.1. Delay-Attacks 4.1. Delay-Attacks
4.1.1. Data Plane Delay Attacks 4.1.1. Data Plane Delay Attacks
Severely delayed messages in a DetNet link can result in the same Delayed messages in a DetNet link can result in the same behavior as
behavior as dropped messages in ordinary networks as the services dropped messages in ordinary networks as the services attached to the
attached to the stream has strict deterministic requirements. stream has strict deterministic requirements.
For a single path scenario, disruption is a real possibility, whereas For a single path scenario, disruption is a real possibility, whereas
in a multipath scenario, large delays or instabilities in one stream in a multipath scenario, large delays or instabilities in one stream
can lead to increased buffer and CPU resources on the elimination can lead to increased buffer and CPU resources on the elimination
bridge. bridge.
A data-plane delay attack on a system controlling substantial moving A data-plane delay attack on a system controlling substantial moving
devices, for example in industrial automation, can cause physical devices, for example in industrial automation, can cause physical
damage. For example, if the network promises a bounded latency of damage. For example, if the network promises a bounded latency of
2ms for a flow, yet the machine receives it with 5ms latency, the 2ms for a flow, yet the machine receives it with 5ms latency, the
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from receiving expected frames thus disrupting expected behavior. from receiving expected frames thus disrupting expected behavior.
o Delaying messages removing an EP from a group can lead to loss of o Delaying messages removing an EP from a group can lead to loss of
privacy as the EP will continue to receive messages even after it privacy as the EP will continue to receive messages even after it
is supposedly removed. is supposedly removed.
4.2. Flow Modification and Spoofing 4.2. Flow Modification and Spoofing
4.2.1. Flow Modification 4.2.1. Flow Modification
ToDo. If the contents of a packet header or body can be modified by the
attacker, this can cause the packet to be routed incorrectly or
dropped, or the payload to be corrupted or subtly modified.
4.2.2. Spoofing 4.2.2. Spoofing
4.2.2.1. Dataplane Spoofing 4.2.2.1. Dataplane Spoofing
Spoofing dataplane messages can result in increased resource Spoofing dataplane messages can result in increased resource
consumptions on the bridges throughout the network as it will consumptions on the bridges throughout the network as it will
increase buffer usage and CPU utilization. This can lead to resource increase buffer usage and CPU utilization. This can lead to resource
exhaustion and/or increased delay. exhaustion and/or increased delay.
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4.4.1. Increased Attack Surface 4.4.1. Increased Attack Surface
Covered briefly in Section 4.3 Covered briefly in Section 4.3
4.4.2. Header Manipulation at Elimination Bridges 4.4.2. Header Manipulation at Elimination Bridges
Covered briefly in Section 4.3 Covered briefly in Section 4.3
4.5. Control or Signaling Packet Modification 4.5. Control or Signaling Packet Modification
ToDo. If the control plane packets are subject to manipulation undetected,
the network can be severely compromised.
4.6. Control or Signaling Packet Injection 4.6. Control or Signaling Packet Injection
ToDo. If an attacker can inject control plane packets undetected, the
network can be severely compromised.
4.7. Reconnaissance 4.7. Reconnaissance
Of all the attacks, this is one of the most difficult to detect and Of all the attacks, this is one of the most difficult to detect and
counter. Often, an attacker will start out by observing the traffic counter. Often, an attacker will start out by observing the traffic
going through the network and use the knowledge gathered in this going through the network and use the knowledge gathered in this
phase to mount future attacks. phase to mount future attacks.
The attacker can, at their leisure, observe over time all aspects of The attacker can, at their leisure, observe over time all aspects of
the messaging and signalling, learning the intent and purpose of all the messaging and signalling, learning the intent and purpose of all
traffic flows. At some later date, possibly at an important time in traffic flows. At some later date, possibly at an important time in
an operational context, the attacker can launch a multi-faceted an operational context, the attacker can launch a multi-faceted
attack, possibly in conjunction with some demand for ransom. attack, possibly in conjunction with some demand for ransom.
The flow-id in the header of the data plane-messages gives an The flow-id in the header of the data plane-messages gives an
attacker a very reliable identifier for DetNet traffic, and this attacker a very reliable identifier for DetNet traffic, and this
traffic has a high probability of going to lucrative targets. traffic has a high probability of going to lucrative targets.
Applications which are ported from a private OT network to the higher
visibility DetNet environment may need to be adapted to limit
distinctive flow properties that could make them susceptible to
reconnaissance.
4.8. Attacks on Time Sync Mechanisms 4.8. Attacks on Time Sync Mechanisms
ToDo. Attacks on time sync mechanisms are addressed in [RFC7384].
4.9. Attacks on Path Choice 4.9. Attacks on Path Choice
This is covered in part in Section 4.3, and as with Replication and This is covered in part in Section 4.3, and as with Replication and
Elimination (Section 4.4, this is relevant for DataPlane messages. Elimination (Section 4.4), this is relevant for DataPlane messages.
5. Security Threat Mitigation 5. Security Threat Mitigation
This section describes a set of measures that can be taken to This section describes a set of measures that can be taken to
mitigate the attacks described in Section 3. These mitigations mitigate the attacks described in Section 3. These mitigations
should be viewed as a toolset that includes several different and should be viewed as a toolset that includes several different and
diverse tools. Each application or system will typically use a diverse tools. Each application or system will typically use a
subset of these tools, based on a system-specific threat analysis. subset of these tools, based on a system-specific threat analysis.
5.1. Path Redundancy 5.1. Path Redundancy
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A DetNet flow that can be forwarded simultaneously over multiple A DetNet flow that can be forwarded simultaneously over multiple
paths. Path replication and elimination [RFC8655] provides paths. Path replication and elimination [RFC8655] provides
resiliency to dropped or delayed packets. This redundancy resiliency to dropped or delayed packets. This redundancy
improves the robustness to failures and to man-in-the-middle improves the robustness to failures and to man-in-the-middle
attacks. attacks.
Related attacks Related attacks
Path redundancy can be used to mitigate various man-in-the-middle Path redundancy can be used to mitigate various man-in-the-middle
attacks, including attacks described in Section 3.2.1, attacks, including attacks described in Section 3.2.1,
Section 3.2.2, Section 3.2.3, and Section 3.2.8. Section 3.2.2, Section 3.2.3, and Section 3.2.8. However it is
also possible that multiple paths may make it more difficult to
locate the source of a MITM attacker.
5.2. Integrity Protection 5.2. Integrity Protection
Description Description
An integrity protection mechanism, such as a Hash-based Message An integrity protection mechanism, such as a Hash-based Message
Authentication Code (HMAC) can be used to mitigate modification Authentication Code (HMAC) can be used to mitigate modification
attacks. Integrity protection can be used on the data plane attacks on IP packets. Integrity protection in the control plane
header, to prevent its modification and tampering. Integrity is discussed in Section 5.6.
protection in the control plane is discussed in Section 5.6.
Packet Sequence Number Integrity Considerations Packet Sequence Number Integrity Considerations
The use of PREOF in a DetNet implementation implies the use of a The use of PREOF in a DetNet implementation implies the use of a
sequence number for each packet. There is a trust relationship sequence number for each packet. There is a trust relationship
between the device that adds the sequence number and the device between the device that adds the sequence number and the device
that removes the sequence number. The sequence number may be end- that removes the sequence number. The sequence number may be end-
to-end source to destination, or may be added/deleted by network to-end source to destination, or may be added/deleted by network
edge devices. The adder and remover(s) have the trust edge devices. The adder and remover(s) have the trust
relationship because they are the ones that ensure that the relationship because they are the ones that ensure that the
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Figure 3: Mapping Attacks to Impact and Mitigations Figure 3: Mapping Attacks to Impact and Mitigations
6. Association of Attacks to Use Cases 6. Association of Attacks to Use Cases
Different attacks can have different impact and/or mitigation Different attacks can have different impact and/or mitigation
depending on the use case, so we would like to make this association depending on the use case, so we would like to make this association
in our analysis. However since there is a potentially unbounded list in our analysis. However since there is a potentially unbounded list
of use cases, we categorize the attacks with respect to the common of use cases, we categorize the attacks with respect to the common
themes of the use cases as identified in the Use Case Common Themes themes of the use cases as identified in the Use Case Common Themes
section of the DetNet Use Cases draft [RFC8578]. section of the DetNet Use Cases [RFC8578].
See also Figure 2 for a mapping of the impact of attacks per use case See also Figure 2 for a mapping of the impact of attacks per use case
by industry. by industry.
6.1. Use Cases by Common Themes 6.1. Use Cases by Common Themes
In this section we review each theme and discuss the attacks that are In this section we review each theme and discuss the attacks that are
applicable to that theme, as well as anything specific about the applicable to that theme, as well as anything specific about the
impact and mitigations for that attack with respect to that theme. impact and mitigations for that attack with respect to that theme.
The table Figure 5 then provides a summary of the attacks that are The table Figure 5 then provides a summary of the attacks that are
applicable to each theme. applicable to each theme.
6.1.1. Network Layer - AVB/TSN Ethernet 6.1.1. Network Layer - AVB/TSN Ethernet
DetNet is expected to run over various transmission mediums, with DetNet is expected to run over various transmission mediums, with
Ethernet being explicitly supported. Attacks such as Delay or Ethernet being explicitly supported. Attacks such as Delay or
Reconnaissance might be implemented differently on a different Reconnaissance might be implemented differently on a different
transmission medium, however the impact on the DetNet as a whole transmission medium, however the impact on the DetNet as a whole
would be essentially the same. We thus conclude that all attacks and would be essentially the same. We thus conclude that all attacks and
impacts that would be applicable to DetNet over Ethernet (i.e. all impacts that would be applicable to DetNet over Ethernet (i.e. all
those named in this draft) would also be applicable to DetNet over those named in this document) would also be applicable to DetNet over
other transmission mediums. other transmission mediums.
With respect to mitigations, some methods are specific to the With respect to mitigations, some methods are specific to the
Ethernet medium, for example time-aware scheduling using 802.1Qbv can Ethernet medium, for example time-aware scheduling using 802.1Qbv can
protect against excessive use of bandwidth at the ingress - for other protect against excessive use of bandwidth at the ingress - for other
mediums, other mitigations would have to be implemented to provide mediums, other mitigations would have to be implemented to provide
analogous protection. analogous protection.
6.1.2. Central Administration 6.1.2. Central Administration
A DetNet network is expected to be controlled by a centralized A DetNet network is expected to be controlled by a centralized
network configuration and control system (CNC). Such a system may be network configuration and control system (CNC). Such a system may be
in a single central location, or it may be distributed across in a single central location, or it may be distributed across
multiple control entities that function together as a unified control multiple control entities that function together as a unified control
system for the network. system for the network.
In this draft we distinguish between attacks on the DetNet Control In this document we distinguish between attacks on the DetNet Control
plane vs. Data plane. But is an attack affecting control plane plane vs. Data plane. But is an attack affecting control plane
packets synonymous with an attack on the CNC itself? For purposes of packets synonymous with an attack on the CNC itself? For purposes of
this draft let us consider an attack on the CNC itself to be out of this document let us consider an attack on the CNC itself to be out
scope, and consider all attacks named in this draft which are of scope, and consider all attacks named in this document which are
relevant to control plane packets to be relevant to this theme, relevant to control plane packets to be relevant to this theme,
including Path Manipulation, Path Choice, Control Packet Modification including Path Manipulation, Path Choice, Control Packet Modification
or Injection, Reconaissance and Attacks on Time Sync Mechanisms. or Injection, Reconaissance and Attacks on Time Sync Mechanisms.
6.1.3. Hot Swap 6.1.3. Hot Swap
A DetNet network is not expected to be "plug and play" - it is A DetNet network is not expected to be "plug and play" - it is
expected that there is some centralized network configuration and expected that there is some centralized network configuration and
control system. However, the ability to "hot swap" components (e.g. control system. However, the ability to "hot swap" components (e.g.
due to malfunction) is similar enough to "plug and play" that this due to malfunction) is similar enough to "plug and play" that this
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present a new attack surface. Does the threat take advantage of any present a new attack surface. Does the threat take advantage of any
aspect of our new Data Flow Info Models? aspect of our new Data Flow Info Models?
This is TBD, thus there are no specific entries in our table, however This is TBD, thus there are no specific entries in our table, however
that does not imply that there could be no relevant attacks. that does not imply that there could be no relevant attacks.
6.1.5. L2 and L3 Integration 6.1.5. L2 and L3 Integration
A DetNet network integrates Layer 2 (bridged) networks (e.g. AVB/TSN A DetNet network integrates Layer 2 (bridged) networks (e.g. AVB/TSN
LAN) and Layer 3 (routed) networks via the use of well-known LAN) and Layer 3 (routed) networks via the use of well-known
protocols such as IPv6, MPLS-PW, and Ethernet. Presumably security protocols such as IP, MPLS-PW, and Ethernet.
considerations applicable directly to those individual protocols is
not specific to DetNet, and thus out of scope for this draft.
However enabling DetNet to coordinate Layer 2 and Layer 3 behavior
will require some additions to existing protocols (see draft-dt-
detnet-dp-alt) and any such new work can introduce new attack
surfaces.
This is TBD, thus there are no specific entries in our table, however There are no specific entries in our table, however that does not
that does not imply that there could be no relevant attacks. imply that there could be no relevant attacks related to L2,L3
integration.
6.1.6. End-to-End Delivery 6.1.6. End-to-End Delivery
Packets sent over DetNet are guaranteed not to be dropped by the Packets sent over DetNet are not to be dropped by the network due to
network due to congestion. (Packets may however be dropped for congestion. (Packets may however intentionally be dropped for
intended reasons, e.g. per security measures). intended reasons, e.g. per security measures).
A Data plane attack may force packets to be dropped, for example a A Data plane attack may force packets to be dropped, for example a
"long" Delay or Replication/Elimination or Flow Modification attack. "long" Delay or Replication/Elimination or Flow Modification attack.
The same result might be obtained by a Control plane attack, e.g. The same result might be obtained by a Control plane attack, e.g.
Path Manipulation or Signaling Packet Modification. Path Manipulation or Signaling Packet Modification.
It may be that such attacks are limited to Internal MITM attackers, It may be that such attacks are limited to Internal MITM attackers,
but other possibilities should be considered. but other possibilities should be considered.
An attack may also cause packets that should not be delivered to be An attack may also cause packets that should not be delivered to be
delivered, such as by forcing packets from one (e.g. replicated) path delivered, such as by forcing packets from one (e.g. replicated) path
to be preferred over another path when they should not be to be preferred over another path when they should not be
(Replication attack), or by Flow Modification, or by Path Choice or (Replication attack), or by Flow Modification, or by Path Choice or
Packet Injection. A Time Sync attack could cause a system that was Packet Injection. A Time Sync attack could cause a system that was
expecting certain packets at certain times to accept unintended expecting certain packets at certain times to accept unintended
packets based on compromised system time or time windowing in the packets based on compromised system time or time windowing in the
scheduler. scheduler.
Packets may also be dropped due to malfunctioning software or
hardware.
6.1.7. Proprietary Deterministic Ethernet Networks 6.1.7. Proprietary Deterministic Ethernet Networks
There are many proprietary non-interoperable deterministic Ethernet- There are many proprietary non-interoperable deterministic Ethernet-
based networks currently available; DetNet is intended to provide an based networks currently available; DetNet is intended to provide an
open-standards-based alternative to such networks. In cases where a open-standards-based alternative to such networks. In cases where a
DetNet intersects with remnants of such networks or their protocols, DetNet intersects with remnants of such networks or their protocols,
such as by protocol emulation or access to such a network via a such as by protocol emulation or access to such a network via a
gateway, new attack surfaces can be opened. gateway, new attack surfaces can be opened.
For example an Inter-Segment or Control plane attack such as Path For example an Inter-Segment or Control plane attack such as Path
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could be used to exploit commands specific to such a protocol, or could be used to exploit commands specific to such a protocol, or
that are interpreted differently by the different protocols or that are interpreted differently by the different protocols or
gateway. gateway.
6.1.9. Deterministic vs Best-Effort Traffic 6.1.9. Deterministic vs Best-Effort Traffic
DetNet is intended to support coexistence of time-sensitive DetNet is intended to support coexistence of time-sensitive
operational (OT, deterministic) traffic and information (IT, "best operational (OT, deterministic) traffic and information (IT, "best
effort") traffic on the same ("unified") network. effort") traffic on the same ("unified") network.
The presence of IT traffic on a network carrying OT traffic has long With DetNet, this coexistance will become more common, and
been considered insecure design [reference needed here]. With mitigations will need to be established. The fact that the IT
DetNet, this coexistance will become more common, and mitigations traffic on a DetNet is limited to a corporate controlled network
will need to be established. The fact that the IT traffic on a makes this a less difficult problem compared to being exposed to the
DetNet is limited to a corporate controlled network makes this a less open Internet, however this aspect of DetNet security should not be
difficult problem compared to being exposed to the open Internet, underestimated.
however this aspect of DetNet security should not be underestimated.
Most of the themes described in this draft address OT (reserved) Most of the themes described in this document address OT (reserved)
streams - this item is intended to address issues related to IT streams - this item is intended to address issues related to IT
traffic on a DetNet. traffic on a DetNet.
An Inter-segment attack can flood the network with IT-type traffic An Inter-segment attack can flood the network with IT-type traffic
with the intent of disrupting handling of IT traffic, and/or the goal with the intent of disrupting handling of IT traffic, and/or the goal
of interfering with OT traffic. Presumably if the stream reservation of interfering with OT traffic. Presumably if the stream reservation
and isolation of the DetNet is well-designed (better-designed than and isolation of the DetNet is well-designed (better-designed than
the attack) then interference with OT traffic should not result from the attack) then interference with OT traffic should not result from
an attack that floods the network with IT traffic. an attack that floods the network with IT traffic.
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be required of a given system, and should define parameters for be required of a given system, and should define parameters for
communicating these kinds of metrics within the network. communicating these kinds of metrics within the network.
Any attack on the system, of any type, can affect its overall Any attack on the system, of any type, can affect its overall
reliability and availability, thus in our table we have marked every reliability and availability, thus in our table we have marked every
attack. Since every DetNet depends to a greater or lesser degree on attack. Since every DetNet depends to a greater or lesser degree on
reliability and availability, this essentially means that all reliability and availability, this essentially means that all
networks have to mitigate all attacks, which to a greater or lesser networks have to mitigate all attacks, which to a greater or lesser
degree defeats the purpose of associating attacks with use cases. It degree defeats the purpose of associating attacks with use cases. It
also underscores the difficulty of designing "extremely high also underscores the difficulty of designing "extremely high
reliability" networks. I hope that in future drafts we can say reliability" networks.
something more useful here.
6.1.23. Redundant Paths 6.1.23. Redundant Paths
DetNet based systems are expected to be implemented with essentially DetNet based systems are expected to be implemented with essentially
arbitrarily high reliability/availability. A strategy used by DetNet arbitrarily high reliability/availability. A strategy used by DetNet
for providing such extraordinarily high levels of reliability is to for providing such extraordinarily high levels of reliability is to
provide redundant paths that can be seamlessly switched between, all provide redundant paths that can be seamlessly switched between, all
the while maintaining the required performance of that system. the while maintaining the required performance of that system.
Replication-related attacks are by definition applicable here. Replication-related attacks are by definition applicable here.
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o OAM traffic generated by the customer. From a DetNet security o OAM traffic generated by the customer. From a DetNet security
point of view, DetNet security considerations for such traffic are point of view, DetNet security considerations for such traffic are
exactly the same as for any other customer data flows. exactly the same as for any other customer data flows.
Thus OAM traffic presents no additional (i.e. OAM-specific) DetNet Thus OAM traffic presents no additional (i.e. OAM-specific) DetNet
security considerations. security considerations.
7. DetNet Technology-Specific Threats 7. DetNet Technology-Specific Threats
Section 3 described threats which are independent of the DetNet Section 3 described threats which are independent of a DetNet
implementation. This section considers threats related to the implementation. This section considers threats specifically related
specific technologies referenced in to the IP- and MPLS-specific aspects of DetNet implementations.
[I-D.ietf-detnet-data-plane-framework] which have not already been
enumerated in Section 3.
As in this document in general, this section only enumerates security The primary security considerations for the data plane specifically
aspects which are unique to providing the specific quality of service are to maintain the integrity of the data and the delivery of the
aspects of DetNet, which are primarily to deliver data flows with associated DetNet service traversing the DetNet network.
extremely low packet loss rates and bounded end-to-end delivery
latency. The primary considerations for the data plane specifically The primary relevant differences between IP and MPLS implementations
are to maintain integrity of data and delivery of the associated are in flow identification and OAM methodologies.
DetNet service traversing the DetNet network.
As noted in [RFC8655], DetNet operates at the IP layer As noted in [RFC8655], DetNet operates at the IP layer
([I-D.ietf-detnet-ip]) and delivers service over sub-layer ([I-D.ietf-detnet-ip]) and delivers service over sub-layer
technologies such as MPLS ([I-D.ietf-detnet-mpls]) and IEEE 802.1 technologies such as MPLS ([I-D.ietf-detnet-mpls]) and IEEE 802.1
Time-Sensitive Networking (TSN) ([I-D.ietf-detnet-ip-over-tsn]). Time-Sensitive Networking (TSN) ([I-D.ietf-detnet-ip-over-tsn]).
Application flows can be protected through whatever means are
provided by the layer and sub-layer technologies. For example,
technology-specific encryption may be used, such as that provided by
IPSec [RFC4301] for IP flows and/or by an underlying sub-net using
MACSec [IEEE802.1AE-2018] for IP over Ethernet (Layer-2) flows.
Application flows can be protected through whatever means is provided However, if the DetNet nodes cannot decrypt IPsec traffic, IPSec may
by the underlying technology. For example, technology-specific not be a valid option; this is because the DetNet IP data plane
encryption may be used, such as that provided by IPSec [RFC4301] for identifies flows via a 6-tuple that consists of two IP addresses, the
IP flows and/or by an underlying sub-net using MACSec transport protocol ID, two transport protocol port numbers and the
[IEEE802.1AE-2018] for IP over Ethernet (Layer-2) flows. DSCP in the IP header. When IPsec is used, the transport header is
encrypted and the next protocol ID is an IPsec protocol, usually ESP,
and not a transport protocol (e.g., neither TCP nor UDP, etc.)
leaving only three components of the 6-tuple, which are the two IP
addresses and the DSCP, which are in general not sufficient to
identify a DetNet flow.
Sections below discuss threats specific to IP, MPLS, and TSN in more Sections below discuss threats specific to IP and MPLS in more
detail. detail.
7.1. IP 7.1. IP
The IP protocol has a long history of security considerations and The IP protocol has a long history of security considerations and
architectural protection mechanisms. From a data plane perspective architectural protection mechanisms. From a data plane perspective
DetNet does not add or modify any IP header information, and its use DetNet does not add or modify any IP header information, and its use
as a DetNet Data Plane does not introduce any new security issues as a DetNet Data Plane does not introduce any new security issues
that were not there before, apart from those already described in the that were not there before, apart from those already described in the
data-plane-independent threats section Section 3. data-plane-independent threats section Section 3.
Thus the security considerations for a DetNet based on an IP data Thus the security considerations for a DetNet based on an IP data
plane are purely inherited from the rich IP Security literature and plane are purely inherited from the rich IP Security literature and
code/application base, and the data-plane-independent section of this code/application base, and the data-plane-independent section of this
document. document.
Maintaining security for IP segments of a DetNet may be more
challenging than for the MPLS segments of the network, given that the
IP segments of the network may reach the edges of the network, which
are more likely to involve interaction with potentially malevolent
outside actors. Conversely MPLS is inherently more secure than IP
since it is internal to routers and it is well-known how to protect
it from outside influence.
Another way to look at DetNet IP security is to consider it in the
light of VPN security; as an industry we have a lot of experience
with VPNs running through networks with other VPNs, it is well known
how to secure the network for that. However for a DetNet we have the
additional subtlety that any possible interaction of one packet with
another can have a potentially deleterious effect on the time
properties of the flows. So the network must provide sufficient
isolation between flows, for example by protecting the forwarding
bandwidth and related resources so that they are available to detnet
traffic, by whatever means are appropriate for that network's data
plane.
7.2. MPLS 7.2. MPLS
An MPLS network carrying DetNet traffic is expected to be a "well- An MPLS network carrying DetNet traffic is expected to be a "well-
managed" network. Given that this is the case, it is difficult for managed" network. Given that this is the case, it is difficult for
an attacker to pass a raw MPLS encoded packet into a network because an attacker to pass a raw MPLS encoded packet into a network because
operators have considerable experience at excluding such packets at operators have considerable experience at excluding such packets at
the network boundaries, as well as excluding MPLS packets being the network boundaries, as well as excluding MPLS packets being
inserted through the use of a tunnel. inserted through the use of a tunnel.
MPLS security is discussed extensively in [RFC5920] ("Security MPLS security is discussed extensively in [RFC5920] ("Security
skipping to change at page 35, line 24 skipping to change at page 36, line 5
One particular problem that has been observed in operational tests of One particular problem that has been observed in operational tests of
TWTT protocols is the ability for two closely but not completely TWTT protocols is the ability for two closely but not completely
synchronized streams to beat and cause a sudden phase hit to one of synchronized streams to beat and cause a sudden phase hit to one of
the streams. This can be mitigated by the careful use of a the streams. This can be mitigated by the careful use of a
scheduling system in the underlying packet transport. scheduling system in the underlying packet transport.
Further consideration of protection against dynamic attacks is work Further consideration of protection against dynamic attacks is work
in progress. in progress.
7.3. TSN 8. IANA Considerations
Editor's Note: To Be Written.
8. Appendix A: DetNet Draft Security-Related Statements
This section collects the various statements in the currently
existing DetNet Working Group drafts. For each draft, the section
name and number of the quoted section is shown. The text shown here
is the work of the original draft authors, quoted verbatim from the
drafts. The intention is to explicitly quote all relevant text, not
to summarize it.
8.1. Architecture (draft 8)
8.1.1. Fault Mitigation (sec 4.5)
One key to building robust real-time systems is to reduce the
infinite variety of possible failures to a number that can be
analyzed with reasonable confidence. DetNet aids in the process by
providing filters and policers to detect DetNet packets received on
the wrong interface, or at the wrong time, or in too great a volume,
and to then take actions such as discarding the offending packet,
shutting down the offending DetNet flow, or shutting down the
offending interface.
It is also essential that filters and service remarking be employed
at the network edge to prevent non-DetNet packets from being mistaken
for DetNet packets, and thus impinging on the resources allocated to
DetNet packets.
There exist techniques, at present and/or in various stages of
standardization, that can perform these fault mitigation tasks that
deliver a high probability that misbehaving systems will have zero
impact on well-behaved DetNet flows, except of course, for the
receiving interface(s) immediately downstream of the misbehaving
device. Examples of such techniques include traffic policing
functions (e.g. [RFC2475]) and separating flows into per-flow rate-
limited queues.
8.1.2. Security Considerations (sec 7)
Security in the context of Deterministic Networking has an added
dimension; the time of delivery of a packet can be just as important
as the contents of the packet, itself. A man-in-the-middle attack,
for example, can impose, and then systematically adjust, additional
delays into a link, and thus disrupt or subvert a real-time
application without having to crack any encryption methods employed.
See [RFC7384] for an exploration of this issue in a related context.
Furthermore, in a control system where millions of dollars of
equipment, or even human lives, can be lost if the DetNet QoS is not
delivered, one must consider not only simple equipment failures,
where the box or wire instantly becomes perfectly silent, but bizarre
errors such as can be caused by software failures. Because there is
essential no limit to the kinds of failures that can occur,
protecting against realistic equipment failures is indistinguishable,
in most cases, from protecting against malicious behavior, whether
accidental or intentional.
Security must cover:
o Protection of the signaling protocol
o Authentication and authorization of the controlling nodes
o Identification and shaping of the flows
8.2. Data Plane Alternatives (draft 4)
8.2.1. Security Considerations (sec 7)
This document does not add any new security considerations beyond
what the referenced technologies already have.
8.3. Problem Statement (draft 5)
8.3.1. Security Considerations (sec 5)
Security in the context of Deterministic Networking has an added
dimension; the time of delivery of a packet can be just as important
as the contents of the packet, itself. A man-in-the-middle attack,
for example, can impose, and then systematically adjust, additional
delays into a link, and thus disrupt or subvert a real-time
application without having to crack any encryption methods employed.
See [RFC7384] for an exploration of this issue in a related context.
Typical control networks today rely on complete physical isolation to
prevent rogue access to network resources. DetNet enables the
virtualization of those networks over a converged IT/OT
infrastructure. Doing so, DetNet introduces an additional risk that
flows interact and interfere with one another as they share physical
resources such as Ethernet trunks and radio spectrum. The
requirement is that there is no possible data leak from and into a
deterministic flow, and in a more general fashion there is no
possible influence whatsoever from the outside on a deterministic
flow. The expectation is that physical resources are effectively
associated with a given flow at a given point of time. In that
model, Time Sharing of physical resources becomes transparent to the
individual flows which have no clue whether the resources are used by
other flows at other times.
Security must cover:
o Protection of the signaling protocol
o Authentication and authorization of the controlling nodes
o Identification and shaping of the flows
o Isolation of flows from leakage and other influences from any
activity sharing physical resources
8.4. Use Cases (draft 11)
8.4.1. (Utility Networks) Security Current Practices and Limitations
(sec 3.2.1)
Grid monitoring and control devices are already targets for cyber
attacks, and legacy telecommunications protocols have many intrinsic
network-related vulnerabilities. For example, DNP3, Modbus,
PROFIBUS/PROFINET, and other protocols are designed around a common
paradigm of request and respond. Each protocol is designed for a
master device such as an HMI (Human Machine Interface) system to send
commands to subordinate slave devices to retrieve data (reading
inputs) or control (writing to outputs). Because many of these
protocols lack authentication, encryption, or other basic security
measures, they are prone to network-based attacks, allowing a
malicious actor or attacker to utilize the request-and-respond system
as a mechanism for command-and-control like functionality. Specific
security concerns common to most industrial control, including
utility telecommunication protocols include the following:
o Network or transport errors (e.g. malformed packets or excessive
latency) can cause protocol failure.
o Protocol commands may be available that are capable of forcing
slave devices into inoperable states, including powering-off
devices, forcing them into a listen-only state, disabling
alarming.
o Protocol commands may be available that are capable of restarting
communications and otherwise interrupting processes.
o Protocol commands may be available that are capable of clearing,
erasing, or resetting diagnostic information such as counters and
diagnostic registers.
o Protocol commands may be available that are capable of requesting
sensitive information about the controllers, their configurations,
or other need-to-know information.
o Most protocols are application layer protocols transported over
TCP; therefore it is easy to transport commands over non-standard
ports or inject commands into authorized traffic flows.
o Protocol commands may be available that are capable of
broadcasting messages to many devices at once (i.e. a potential
DoS).
o Protocol commands may be available to query the device network to
obtain defined points and their values (i.e. a configuration
scan).
o Protocol commands may be available that will list all available
function codes (i.e. a function scan).
o These inherent vulnerabilities, along with increasing connectivity
between IT an OT networks, make network-based attacks very
feasible.
o Simple injection of malicious protocol commands provides control
over the target process. Altering legitimate protocol traffic can
also alter information about a process and disrupt the legitimate
controls that are in place over that process. A man-in-the-middle
attack could provide both control over a process and
misrepresentation of data back to operator consoles.
8.4.2. (Utility Networks) Security Trends in Utility Networks (sec
3.3.3)
Although advanced telecommunications networks can assist in
transforming the energy industry by playing a critical role in
maintaining high levels of reliability, performance, and
manageability, they also introduce the need for an integrated
security infrastructure. Many of the technologies being deployed to
support smart grid projects such as smart meters and sensors can
increase the vulnerability of the grid to attack. Top security
concerns for utilities migrating to an intelligent smart grid
telecommunications platform center on the following trends:
o Integration of distributed energy resources
o Proliferation of digital devices to enable management, automation,
protection, and control
o Regulatory mandates to comply with standards for critical
infrastructure protection
o Migration to new systems for outage management, distribution
automation, condition-based maintenance, load forecasting, and
smart metering
o Demand for new levels of customer service and energy management
This development of a diverse set of networks to support the
integration of microgrids, open-access energy competition, and the
use of network-controlled devices is driving the need for a converged
security infrastructure for all participants in the smart grid,
including utilities, energy service providers, large commercial and
industrial, as well as residential customers. Securing the assets of
electric power delivery systems (from the control center to the
substation, to the feeders and down to customer meters) requires an
end-to-end security infrastructure that protects the myriad of
telecommunications assets used to operate, monitor, and control power
flow and measurement.
"Cyber security" refers to all the security issues in automation and
telecommunications that affect any functions related to the operation
of the electric power systems. Specifically, it involves the
concepts of:
o Integrity : data cannot be altered undetectably
o Authenticity : the telecommunications parties involved must be
validated as genuine
o Authorization : only requests and commands from the authorized
users can be accepted by the system
o Confidentiality : data must not be accessible to any
unauthenticated users
When designing and deploying new smart grid devices and
telecommunications systems, it is imperative to understand the
various impacts of these new components under a variety of attack
situations on the power grid. Consequences of a cyber attack on the
grid telecommunications network can be catastrophic. This is why
security for smart grid is not just an ad hoc feature or product,
it's a complete framework integrating both physical and Cyber
security requirements and covering the entire smart grid networks
from generation to distribution. Security has therefore become one
of the main foundations of the utility telecom network architecture
and must be considered at every layer with a defense-in-depth
approach. Migrating to IP based protocols is key to address these
challenges for two reasons:
o IP enables a rich set of features and capabilities to enhance the
security posture
o IP is based on open standards, which allows interoperability
between different vendors and products, driving down the costs
associated with implementing security solutions in OT networks.
Securing OT (Operation technology) telecommunications over packet-
switched IP networks follow the same principles that are foundational
for securing the IT infrastructure, i.e., consideration must be given
to enforcing electronic access control for both person-to-machine and
machine-to-machine communications, and providing the appropriate
levels of data privacy, device and platform integrity, and threat
detection and mitigation.
Existing power automation security standards can inform network
security. For example the NERC CIP (North American Electric
Reliability Corporation Critical Infrastructure Protection) plan is a
set of requirements designed to secure the assets required for
operating North America's bulk electric system. Another standardized
security control technique is Segmentation (zones and conduits
including access control).
The requirements in Industrial Automation and Control Systems (IACS)
are quite similar, especially in new scenarios such as Industry 4.0/
Digital Factory where workflows and protocols cross zones, segments,
and entities. IEC 62443 (ISA99) defines security for IACS, typically
for installations in other critical infrastructure such as oil and
gas.
Availability and integrity are the most important security objectives
for the lower layers of such networks; confidentiality and privacy
are relevant if customer or market data is involved, typically
handled by higher layers.
8.4.3. (BAS) Security Considerations (sec 4.2.4)
When BAS field networks were developed it was assumed that the field
networks would always be physically isolated from external networks
and therefore security was not a concern. In today's world many BASs
are managed remotely and are thus connected to shared IP networks and
so security is definitely a concern, yet security features are not
available in the majority of BAS field network deployments .
The management network, being an IP-based network, has the protocols
available to enable network security, but in practice many BAS
systems do not implement even the available security features such as
device authentication or encryption for data in transit.
8.4.4. (6TiSCH) Security Considerations (sec 5.3.3)
On top of the classical requirements for protection of control
signaling, it must be noted that 6TiSCH networks operate on limited
resources that can be depleted rapidly in a DoS attack on the system,
for instance by placing a rogue device in the network, or by
obtaining management control and setting up unexpected additional
paths.
8.4.5. (Cellular radio) Security Considerations (sec 6.1.5)
Establishing time-sensitive streams in the network entails reserving
networking resources for long periods of time. It is important that
these reservation requests be authenticated to prevent malicious
reservation attempts from hostile nodes (or accidental
misconfiguration). This is particularly important in the case where
the reservation requests span administrative domains. Furthermore,
the reservation information itself should be digitally signed to
reduce the risk of a legitimate node pushing a stale or hostile
configuration into another networking node.
Note: This is considered important for the security policy of the
network, but does not affect the core DetNet architecture and design.
8.4.6. (Industrial M2M) Communication Today (sec 7.2)
Industrial network scenarios require advanced security solutions.
Many of the current industrial production networks are physically
separated. Preventing critical flows from be leaked outside a domain
is handled today by filtering policies that are typically enforced in
firewalls.
9. IANA Considerations
This memo includes no requests from IANA. This memo includes no requests from IANA.
10. Security Considerations 9. Security Considerations
The security considerations of DetNet networks are presented The security considerations of DetNet networks are presented
throughout this document. throughout this document.
11. Informative References 10. Informative References
[ARINC664P7] [ARINC664P7]
ARINC, "ARINC 664 Aircraft Data Network, Part 7, Avionics ARINC, "ARINC 664 Aircraft Data Network, Part 7, Avionics
Full-Duplex Switched Ethernet Network", 2009. Full-Duplex Switched Ethernet Network", 2009.
[I-D.ietf-detnet-data-plane-framework] [I-D.ietf-detnet-data-plane-framework]
Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A., Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
Bryant, S., and J. Korhonen, "DetNet Data Plane Bryant, S., and J. Korhonen, "DetNet Data Plane
Framework", draft-ietf-detnet-data-plane-framework-02 Framework", draft-ietf-detnet-data-plane-framework-03
(work in progress), September 2019. (work in progress), October 2019.
[I-D.ietf-detnet-ip] [I-D.ietf-detnet-ip]
Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A., Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
Bryant, S., and J. Korhonen, "DetNet Data Plane: IP", Bryant, S., and J. Korhonen, "DetNet Data Plane: IP",
draft-ietf-detnet-ip-03 (work in progress), October 2019. draft-ietf-detnet-ip-04 (work in progress), November 2019.
[I-D.ietf-detnet-ip-over-tsn] [I-D.ietf-detnet-ip-over-tsn]
Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet
Data Plane: IP over IEEE 802.1 Time Sensitive Networking Data Plane: IP over IEEE 802.1 Time Sensitive Networking
(TSN)", draft-ietf-detnet-ip-over-tsn-01 (work in (TSN)", draft-ietf-detnet-ip-over-tsn-01 (work in
progress), October 2019. progress), October 2019.
[I-D.ietf-detnet-mpls] [I-D.ietf-detnet-mpls]
Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A., Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS", Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS",
draft-ietf-detnet-mpls-03 (work in progress), October draft-ietf-detnet-mpls-04 (work in progress), November
2019. 2019.
[I-D.varga-detnet-service-model] [I-D.varga-detnet-service-model]
Varga, B. and J. Farkas, "DetNet Service Model", draft- Varga, B. and J. Farkas, "DetNet Service Model", draft-
varga-detnet-service-model-02 (work in progress), May varga-detnet-service-model-02 (work in progress), May
2017. 2017.
[IEEE1588] [IEEE1588]
IEEE, "IEEE 1588 Standard for a Precision Clock IEEE, "IEEE 1588 Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and Synchronization Protocol for Networked Measurement and
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1275 Market Street 1275 Market Street
San Francisco, CA 94103 San Francisco, CA 94103
USA USA
Phone: +1 415 645 4726 Phone: +1 415 645 4726
Email: ethan.grossman@dolby.com Email: ethan.grossman@dolby.com
URI: http://www.dolby.com URI: http://www.dolby.com
Andrew J. Hacker Andrew J. Hacker
MistIQ Technologies, Inc MistIQ Technologies, Inc
Harrisburg, PA Harrisburg, PA
USA USA
Phone:
Email: ajhacker@mistiqtech.com Email: ajhacker@mistiqtech.com
URI: http://www.mistiqtech.com URI: http://www.mistiqtech.com
Subir Das Subir Das
Applied Communication Sciences Applied Communication Sciences
150 Mount Airy Road, Basking Ridge 150 Mount Airy Road, Basking Ridge
New Jersey, 07920 New Jersey, 07920
USA USA
Email: sdas@appcomsci.com Email: sdas@appcomsci.com
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