--- 1/draft-ietf-detnet-security-00.txt 2017-10-30 12:13:21.825935616 -0700 +++ 2/draft-ietf-detnet-security-01.txt 2017-10-30 12:13:21.901937436 -0700 @@ -1,31 +1,31 @@ Internet Engineering Task Force T. Mizrahi Internet-Draft MARVELL Intended status: Informational E. Grossman, Ed. -Expires: April 2, 2018 DOLBY +Expires: May 3, 2018 DOLBY A. Hacker MISTIQ S. Das Applied Communication Sciences J. Dowdell Airbus Defence and Space H. Austad Cisco Systems K. Stanton INTEL N. Finn HUAWEI - September 29, 2017 + October 30, 2017 Deterministic Networking (DetNet) Security Considerations - draft-ietf-detnet-security-00 + draft-ietf-detnet-security-01 Abstract A deterministic network is one that can carry data flows for real- time applications with extremely low data loss rates and bounded latency. Deterministic networks have been successfully deployed in real-time operational technology (OT) applications for some years (for example [ARINC664P7]). However, such networks are typically isolated from external access, and thus the security threat from external attackers is low. IETF Deterministic Networking (DetNet) @@ -51,21 +51,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 2, 2018. + This Internet-Draft will expire on May 3, 2018. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -77,110 +77,111 @@ Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Security Threats . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 6 3.2. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 7 3.2.1. Delay . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2.1.1. Delay Attack . . . . . . . . . . . . . . . . . . 7 - 3.2.2. DetNet Flow Identification . . . . . . . . . . . . . 7 - 3.2.2.1. DetNet Flow Modification or Spoofing . . . . . . 7 + 3.2.2. DetNet Flow Modification or Spoofing . . . . . . . . 7 3.2.3. Resource Segmentation or Slicing . . . . . . . . . . 7 3.2.3.1. Inter-segment Attack . . . . . . . . . . . . . . 7 - 3.2.4. Packet Replication and Elimination . . . . . . . . . 7 + 3.2.4. Packet Replication and Elimination . . . . . . . . . 8 3.2.4.1. Replication: Increased Attack Surface . . . . . . 8 3.2.4.2. Replication-related Header Manipulation . . . . . 8 - 3.2.5. Path Choice . . . . . . . . . . . . . . . . . . . . . 8 3.2.5.1. Path Manipulation . . . . . . . . . . . . . . . . 8 - 3.2.5.2. Path Choice: Increased Attack Surface . . . . . . 8 + 3.2.5.2. Path Choice: Increased Attack Surface . . . . . . 9 3.2.6. Control Plane . . . . . . . . . . . . . . . . . . . . 9 3.2.6.1. Control or Signaling Packet Modification . . . . 9 3.2.6.2. Control or Signaling Packet Injection . . . . . . 9 3.2.7. Scheduling or Shaping . . . . . . . . . . . . . . . . 9 3.2.7.1. Reconnaissance . . . . . . . . . . . . . . . . . 9 3.2.8. Time Synchronization Mechanisms . . . . . . . . . . . 9 3.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 9 4. Security Threat Impacts . . . . . . . . . . . . . . . . . . . 10 - 4.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 10 - 4.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 11 - 4.1.2. Control Plane Delay Attacks . . . . . . . . . . . . . 11 - 4.2. Flow Identification and Spoofing . . . . . . . . . . . . 11 - 4.2.1. Flow identification . . . . . . . . . . . . . . . . . 11 - 4.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 12 - 4.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 12 - 4.2.2.2. Control Plane Spoofing . . . . . . . . . . . . . 12 - 4.3. Segmentation attacks (injection) . . . . . . . . . . . . 12 - 4.3.1. Data Plane Segmentation . . . . . . . . . . . . . . . 12 - 4.3.2. Control Plane segmentation . . . . . . . . . . . . . 13 - 4.4. Replication and Elimination . . . . . . . . . . . . . . . 13 - 4.4.1. Increased Attack Surface . . . . . . . . . . . . . . 13 - 4.4.2. Header Manipulation at Elimination Bridges . . . . . 13 - 4.5. Impact of Attacks to Path Choice . . . . . . . . . . . . 13 - 4.6. Impact of Attacks by Use Case Industry . . . . . . . . . 13 - 5. Security Threat Mitigation . . . . . . . . . . . . . . . . . 15 + 4.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 13 + 4.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 13 + 4.1.2. Control Plane Delay Attacks . . . . . . . . . . . . . 13 + 4.2. Flow Modification and Spoofing . . . . . . . . . . . . . 14 + 4.2.1. Flow Modification . . . . . . . . . . . . . . . . . . 14 + 4.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 14 + 4.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 14 + 4.2.2.2. Control Plane Spoofing . . . . . . . . . . . . . 14 + 4.3. Segmentation attacks (injection) . . . . . . . . . . . . 15 + 4.3.1. Data Plane Segmentation . . . . . . . . . . . . . . . 15 + 4.3.2. Control Plane segmentation . . . . . . . . . . . . . 15 + 4.4. Replication and Elimination . . . . . . . . . . . . . . . 15 + 4.4.1. Increased Attack Surface . . . . . . . . . . . . . . 15 + 4.4.2. Header Manipulation at Elimination Bridges . . . . . 15 + 4.5. Control or Signaling Packet Modification . . . . . . . . 16 + 4.6. Control or Signaling Packet Injection . . . . . . . . . . 16 + 4.7. Reconnaissance . . . . . . . . . . . . . . . . . . . . . 16 + 4.8. Attacks on Time Sync Mechanisms . . . . . . . . . . . . . 16 + 4.9. Attacks on Path Choice . . . . . . . . . . . . . . . . . 16 + 5. Security Threat Mitigation . . . . . . . . . . . . . . . . . 16 5.1. Path Redundancy . . . . . . . . . . . . . . . . . . . . . 16 - 5.2. Integrity Protection . . . . . . . . . . . . . . . . . . 16 - 5.3. DetNet Node Authentication . . . . . . . . . . . . . . . 16 + 5.2. Integrity Protection . . . . . . . . . . . . . . . . . . 17 + 5.3. DetNet Node Authentication . . . . . . . . . . . . . . . 17 5.4. Encryption . . . . . . . . . . . . . . . . . . . . . . . 17 - 5.5. Control and Signaling Message Protection . . . . . . . . 17 - 5.6. Dynamic Performance Analytics . . . . . . . . . . . . . . 17 + 5.5. Control and Signaling Message Protection . . . . . . . . 18 + 5.6. Dynamic Performance Analytics . . . . . . . . . . . . . . 18 5.7. Mitigation Summary . . . . . . . . . . . . . . . . . . . 18 - 6. Association of Attacks to Use Cases . . . . . . . . . . . . . 19 - 6.1. Use Cases by Common Themes . . . . . . . . . . . . . . . 19 - 6.1.1. Network Layer - AVB/TSN Ethernet . . . . . . . . . . 19 - 6.1.2. Central Administration . . . . . . . . . . . . . . . 19 - 6.1.3. Hot Swap . . . . . . . . . . . . . . . . . . . . . . 20 - 6.1.4. Data Flow Information Models . . . . . . . . . . . . 20 - 6.1.5. L2 and L3 Integration . . . . . . . . . . . . . . . . 20 - 6.1.6. End-to-End Delivery . . . . . . . . . . . . . . . . . 20 - 6.1.7. Proprietary Deterministic Ethernet Networks . . . . . 20 - 6.1.8. Replacement for Proprietary Fieldbuses . . . . . . . 20 - 6.1.9. Deterministic vs Best-Effort Traffic . . . . . . . . 21 - 6.1.10. Deterministic Flows . . . . . . . . . . . . . . . . . 21 - 6.1.11. Unused Reserved Bandwidth . . . . . . . . . . . . . . 21 - 6.1.12. Interoperability . . . . . . . . . . . . . . . . . . 21 - 6.1.13. Cost Reductions . . . . . . . . . . . . . . . . . . . 21 - 6.1.14. Insufficiently Secure Devices . . . . . . . . . . . . 22 - 6.1.15. DetNet Network Size . . . . . . . . . . . . . . . . . 22 - 6.1.16. Multiple Hops . . . . . . . . . . . . . . . . . . . . 22 - 6.1.17. Level of Service . . . . . . . . . . . . . . . . . . 22 - 6.1.18. Bounded Latency . . . . . . . . . . . . . . . . . . . 23 - 6.1.19. Low Latency . . . . . . . . . . . . . . . . . . . . . 23 - 6.1.20. Symmetrical Path Delays . . . . . . . . . . . . . . . 23 - 6.1.21. Reliability and Availability . . . . . . . . . . . . 23 - 6.1.22. Redundant Paths . . . . . . . . . . . . . . . . . . . 24 - 6.1.23. Security Measures . . . . . . . . . . . . . . . . . . 24 - 6.2. Attack Types by Use Case Common Theme . . . . . . . . . . 24 - 7. Appendix A: DetNet Draft Security-Related Statements . . . . 26 - 7.1. Architecture (draft 8) . . . . . . . . . . . . . . . . . 27 - 7.1.1. Fault Mitigation (sec 4.5) . . . . . . . . . . . . . 27 - 7.1.2. Security Considerations (sec 7) . . . . . . . . . . . 27 - 7.2. Data Plane Alternatives (draft 4) . . . . . . . . . . . . 28 - 7.2.1. Security Considerations (sec 7) . . . . . . . . . . . 28 - 7.3. Problem Statement (draft 5) . . . . . . . . . . . . . . . 28 - 7.3.1. Security Considerations (sec 5) . . . . . . . . . . . 28 - 7.4. Use Cases (draft 11) . . . . . . . . . . . . . . . . . . 29 + 6. Association of Attacks to Use Cases . . . . . . . . . . . . . 20 + 6.1. Use Cases by Common Themes . . . . . . . . . . . . . . . 20 + 6.1.1. Network Layer - AVB/TSN Ethernet . . . . . . . . . . 20 + 6.1.2. Central Administration . . . . . . . . . . . . . . . 21 + 6.1.3. Hot Swap . . . . . . . . . . . . . . . . . . . . . . 21 + 6.1.4. Data Flow Information Models . . . . . . . . . . . . 22 + 6.1.5. L2 and L3 Integration . . . . . . . . . . . . . . . . 22 + 6.1.6. End-to-End Delivery . . . . . . . . . . . . . . . . . 22 + 6.1.7. Proprietary Deterministic Ethernet Networks . . . . . 23 + 6.1.8. Replacement for Proprietary Fieldbuses . . . . . . . 23 + 6.1.9. Deterministic vs Best-Effort Traffic . . . . . . . . 23 + 6.1.10. Deterministic Flows . . . . . . . . . . . . . . . . . 24 + 6.1.11. Unused Reserved Bandwidth . . . . . . . . . . . . . . 24 + 6.1.12. Interoperability . . . . . . . . . . . . . . . . . . 24 + 6.1.13. Cost Reductions . . . . . . . . . . . . . . . . . . . 25 + 6.1.14. Insufficiently Secure Devices . . . . . . . . . . . . 25 + 6.1.15. DetNet Network Size . . . . . . . . . . . . . . . . . 25 + 6.1.16. Multiple Hops . . . . . . . . . . . . . . . . . . . . 26 + 6.1.17. Level of Service . . . . . . . . . . . . . . . . . . 26 + 6.1.18. Bounded Latency . . . . . . . . . . . . . . . . . . . 27 + 6.1.19. Low Latency . . . . . . . . . . . . . . . . . . . . . 27 + 6.1.20. Symmetrical Path Delays . . . . . . . . . . . . . . . 27 + 6.1.21. Reliability and Availability . . . . . . . . . . . . 27 + 6.1.22. Redundant Paths . . . . . . . . . . . . . . . . . . . 28 + 6.1.23. Security Measures . . . . . . . . . . . . . . . . . . 28 + 6.2. Attack Types by Use Case Common Theme . . . . . . . . . . 28 + 7. Appendix A: DetNet Draft Security-Related Statements . . . . 30 + 7.1. Architecture (draft 8) . . . . . . . . . . . . . . . . . 31 + 7.1.1. Fault Mitigation (sec 4.5) . . . . . . . . . . . . . 31 + 7.1.2. Security Considerations (sec 7) . . . . . . . . . . . 31 + 7.2. Data Plane Alternatives (draft 4) . . . . . . . . . . . . 32 + 7.2.1. Security Considerations (sec 7) . . . . . . . . . . . 32 + 7.3. Problem Statement (draft 5) . . . . . . . . . . . . . . . 32 + 7.3.1. Security Considerations (sec 5) . . . . . . . . . . . 32 + 7.4. Use Cases (draft 11) . . . . . . . . . . . . . . . . . . 33 7.4.1. (Utility Networks) Security Current Practices and - Limitations (sec 3.2.1) . . . . . . . . . . . . . . . 29 + Limitations (sec 3.2.1) . . . . . . . . . . . . . . . 33 7.4.2. (Utility Networks) Security Trends in Utility - Networks (sec 3.3.3) . . . . . . . . . . . . . . . . 30 - 7.4.3. (BAS) Security Considerations (sec 4.2.4) . . . . . . 32 - 7.4.4. (6TiSCH) Security Considerations (sec 5.3.3) . . . . 32 - 7.4.5. (Cellular radio) Security Considerations (sec 6.1.5) 32 - 7.4.6. (Industrial M2M) Communication Today (sec 7.2) . . . 33 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 - 9. Security Considerations . . . . . . . . . . . . . . . . . . . 33 - 10. Informative References . . . . . . . . . . . . . . . . . . . 33 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 + Networks (sec 3.3.3) . . . . . . . . . . . . . . . . 34 + 7.4.3. (BAS) Security Considerations (sec 4.2.4) . . . . . . 36 + 7.4.4. (6TiSCH) Security Considerations (sec 5.3.3) . . . . 36 + 7.4.5. (Cellular radio) Security Considerations (sec 6.1.5) 36 + 7.4.6. (Industrial M2M) Communication Today (sec 7.2) . . . 37 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37 + 9. Security Considerations . . . . . . . . . . . . . . . . . . . 37 + 10. Informative References . . . . . . . . . . . . . . . . . . . 37 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 1. Introduction Security is of particularly high importance in DetNet networks because many of the use cases which are enabled by DetNet [I-D.ietf-detnet-use-cases] include control of physical devices (power grid components, industrial controls, building controls) which can have high operational costs for failure, and present potentially attractive targets for cyber-attackers. @@ -202,24 +203,23 @@ the flow o Provide explicit routes for DetNet flows that do not rapidly change with the network topology 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 path This draft includes sections on threat modeling and analysis, threat - impact and mitigation, and the association of various attacks with - various use cases both by industry and based on the Use Case Common - Themes section of the DetNet Use Cases draft - [I-D.ietf-detnet-use-cases]. + impact and mitigation, and the association of attacks with use cases + based on the Use Case Common Themes section of the DetNet Use Cases + draft [I-D.ietf-detnet-use-cases]. This draft also provides context for the DetNet security considerations by collecting into one place Section 7 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 @@ -245,43 +245,52 @@ many Affected users, Discoverability. PTP Precision Time Protocol [IEEE1588] 3. Security Threats This section presents a threat model, and analyzes the possible threats in a DetNet-enabled network. We distinguish control plane threats from data plane threats. The - attack surface may be the same, but the types of attacks are - different. For example, a delay attack is more relevant to data - plane than to control plane. There is also a difference in terms of - security solutions: the way you secure the data plane is often - different than the way you secure the control plane. + attack surface may be the same, but the types of attacks as well as + the motivation behind them, are different. For example, a delay + attack is more relevant to data plane than to control plane. There + is also a difference in terms of security solutions: the way you + secure the data plane is often different than the way you secure the + control plane. 3.1. Threat Model The threat model used in this memo is based on the threat model of Section 3.1 of [RFC7384]. This model classifies attackers based on two criteria: o Internal vs. external: internal attackers either have access to a trusted segment of the network or possess the encryption or authentication keys. External attackers, on the other hand, do not have the keys and have access only to the encrypted or authenticated traffic. o Man in the Middle (MITM) vs. packet injector: MITM attackers are located in a position that allows interception and modification of in-flight protocol packets, whereas a traffic injector can only attack by generating protocol packets. + Care has also been taken to adhere to Section 5 of [RFC3552], both + with respect to what attacks are considered out-of-scope for this + document, but also what is considered to be the most common threats + (explored furhter in Section 3.2. Most of the direct threats to + DetNet are Active attacks, but it is highly suggested that DetNet + application developers take appropriate measures to protect the + content of the streams from passive attacks. + DetNet-Service, one of the service scenarios described in [I-D.varga-detnet-service-model], is the case where a service connects DetNet networking islands, i.e. two or more otherwise independent DetNet network domains are connected via a link that is not intrinsically part of either network. This implies that there could be DetNet traffic flowing over a non-DetNet link, which may provide an attacker with an advantageous opportunity to tamper with DetNet traffic. The security properties of non-DetNet links are outside of the scope of DetNet Security, but it should be noted that use of non-DetNet services to interconnect DetNet networks merits @@ -292,38 +301,30 @@ 3.2.1. Delay 3.2.1.1. Delay Attack An attacker can maliciously delay DetNet data flow traffic. By delaying the traffic, the attacker can compromise the service of applications that are sensitive to high delays or to high delay variation. -3.2.2. DetNet Flow Identification - -3.2.2.1. 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 way that causes the DetNet flow identification mechanisms to misclassify the flow. Alternatively, the attacker can inject traffic that is tailored to appear as if it belongs to a legitimate DetNet flow. The potential consequence is that the DetNet flow resource allocation cannot guarantee the performance that is expected when the flow identification works correctly. - Note that in some cases there may be an 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 involved, for purposes of this - draft we assume they are encrypted and/or integrity-protected from - external attackers. - 3.2.3. Resource Segmentation or Slicing 3.2.3.1. Inter-segment Attack An attacker can inject traffic, consuming network device resources, thereby affecting DetNet flows. This can be performed using non- DetNet traffic that affects DetNet traffic, or by using DetNet traffic from one DetNet flow that affects traffic from different DetNet flows. @@ -387,24 +389,31 @@ 3.2.6.2. Control or Signaling Packet Injection An attacker can maliciously inject control packets in order to disrupt or manipulate the DetNet path/resource allocation. 3.2.7. Scheduling or Shaping 3.2.7.1. Reconnaissance - A passive eavesdropper can gather information about en route DetNet - flows, e.g., the number of DetNet flows, their bandwidths, and their - schedules. The gathered information can later be used to invoke - other attacks on some or all of the flows. + A passive eavesdropper can identify DetNet flows and then gather + information about en route DetNet flows, e.g., the number of DetNet + flows, their bandwidths, and their schedules. The gathered + information can later be used to invoke other attacks on some or all + of the flows. + + Note that in some cases DetNet flows may be identified based on an + 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 + involved, for purposes of this draft we assume they are encrypted + and/or integrity-protected from external attackers. 3.2.8. Time Synchronization Mechanisms An attacker can use any of the attacks described in [RFC7384] to attack the synchronization protocol, thus affecting the DetNet service. 3.3. Threat Summary A summary of the attacks that were discussed in this section is @@ -441,77 +450,184 @@ +-----------------------------------------+----+----+----+----+ |Reconnaissance | + | | + | | +-----------------------------------------+----+----+----+----+ |Attacks on Time Sync Mechanisms | + | + | + | + | +-----------------------------------------+----+----+----+----+ Figure 1: Threat Analysis Summary 4. Security Threat Impacts - This section describes the impact of the attacks described in - Section 3. Mitigations are discussed further in Section 5. + This section describes and rates the impact of the attacks described + in Section 3. In this section, the impacts as described assume that + the associated mitigation is not present or has failed. Mitigations + are discussed in Section 5. In computer security, the impact (or consequence) of an incident can be measured in loss of confidentiality, integrity or availability of - information. In other words, this section describes the effect of a - successful attack. The scope is limited to the effect of a - successful attack on DetNet itself, not the applications that _use_ - Detnet as this is highly application specific. + information. + + DetNet raises these stakes significantly for OT applications, + 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 with its associated devices, services and protocols. + + The severity of various components of the impact of a successful + vulnerability exploit to use cases by industry is available in more + detail in [I-D.ietf-detnet-use-cases]. Each of the use cases in the + DetNet Use Cases draft is represented in the table below, including + Pro Audio, Electrical Utilities, Industrial M2M (split into two + areas, M2M Data Gathering and M2M Control Loop), and others. + + Components of Impact (left column) include Criticality of Failure, + Effects of Failure, Recovery, and DetNet Functional Dependence. + Criticality of failure summarizes the seriousness of the impact. The + impact of a resulting failure can affect many different metrics that + vary greatly in scope and severity. In order to reduce the number of + variables, only the following were included: Financial, Health and + Safety, People well being, Affect on a single organization, and + affect on multiple organizations. Recovery outlines how long it + would take for an affected use case to get back to its pre-failure + state (Recovery time objective, RTO), and how much of the original + service would be lost in between the time of service failure and + recovery to original state (Recovery Point Objective, RPO). DetNet + dependence maps how much the following DetNet service objectives + contribute to impact of failure: Time dependency, data integrity, + source node integrity, availability, latency/jitter. + + The scale of the Impact mappings is low, medium, and high. In some + use cases there may be a multitude of specific applications in which + DetNet is used. For simplicity this section attempts to average the + varied impacts of different applications. This section does not + address the overall risk of a certain impact which would require the + likelihood of a failure happening. + + In practice any such ratings will vary from case to case; the ratings + shown here are given as examples. + + Table, Part One (of Two) + +------------------+-----------------------------------------+-----+ + | | Pro A | Util | Bldg |Wire- | Cell |M2M |M2M | + | | | | | less | |Data |Ctrl | + +------------------+-----------------------------------------+-----+ + | Criticality | Med | Hi | Low | Med | Med | Med | Med | + +------------------+-----------------------------------------+-----+ + | Effects + +------------------+-----------------------------------------+-----+ + | Financial | Med | Hi | Med | Med | Low | Med | Med | + +------------------+-----------------------------------------+-----+ + | Health/Safety | Med | Hi | Hi | Med | Med | Med | Med | + +------------------+-----------------------------------------+-----+ + | People WB | Med | Hi | Hi | Low | Hi | Low | Low | + +------------------+-----------------------------------------+-----+ + | Effect 1 org | Hi | Hi | Med | Hi | Med | Med | Med | + +------------------+-----------------------------------------+-----+ + | Effect >1 org | Med | Hi | Low | Med | Med | Med | Med | + +------------------+-----------------------------------------+-----+ + |Recovery + +------------------+-----------------------------------------+-----+ + | Recov Time Obj | Med | Hi | Med | Hi | Hi | Hi | Hi | + +------------------+-----------------------------------------+-----+ + | Recov Point Obj | Med | Hi | Low | Med | Low | Hi | Hi | + +------------------+-----------------------------------------+-----+ + |DetNet Dependence + +------------------+-----------------------------------------+-----+ + | Time Dependency | Hi | Hi | Low | Hi | Med | Low | Hi | + +------------------+-----------------------------------------+-----+ + | Latency/Jitter | Hi | Hi | Med | Med | Low | Low | Hi | + +------------------+-----------------------------------------+-----+ + | Data Integrity | Hi | Hi | Med | Hi | Low | Hi | Low | + +------------------+-----------------------------------------+-----+ + | Src Node Integ | Hi | Hi | Med | Hi | Med | Hi | Hi | + +------------------+-----------------------------------------+-----+ + | Availability | Hi | Hi | Med | Hi | Low | Hi | Hi | + +------------------+-----------------------------------------+-----+ + + Table, Part Two (of Two) + +------------------+--------------------------+ + | | Mining | Block | Network | + | | | Chain | Slicing | + +------------------+--------------------------+ + | Criticality | Hi | Med | Hi | + +------------------+--------------------------+ + | Effects + +------------------+--------------------------+ + | Financial | Hi | Hi | Hi | + +------------------+--------------------------+ + | Health/Safety | Hi | Low | Med | + +------------------+--------------------------+ + | People WB | Hi | Low | Med | + +------------------+--------------------------+ + | Effect 1 org | Hi | Hi | Hi | + +------------------+--------------------------+ + | Effect >1 org | Hi | Low | Hi | + +------------------+--------------------------+ + |Recovery + +------------------+--------------------------+ + | Recov Time Obj | Hi | Low | Hi | + +------------------+--------------------------+ + | Recov Point Obj | Hi | Low | Hi | + +------------------+--------------------------+ + |DetNet Dependence + +------------------+--------------------------+ + | Time Dependency | Hi | Low | Hi | + +------------------+--------------------------+ + | Latency/Jitter | Hi | Low | Hi | + +------------------+--------------------------+ + | Data Integrity | Hi | Hi | Hi | + +------------------+--------------------------+ + | Src Node Integ | Hi | Hi | Hi | + +------------------+--------------------------+ + | Availability | Hi | Hi | Hi | + +------------------+--------------------------+ + + Figure 2: Impact of Attacks by Use Case Industry + + The rest of this section will cover impact of the different groups in + more detail. 4.1. Delay-Attacks + 4.1.1. Data Plane Delay Attacks - Dropped messages can result in stream instability. If only a single - path is used, the entire stream can be disrupted. In a multipath - scenario, large delays on one stream can lead to increased buffer and - CPU resources on the elimination bridge. + Severely delayed messages in a DetNet link can result in the same + behavior as dropped messages in ordinary networks as the services + attached to the stream has strict deterministic requirements. - If the attack is carried out on a sole link (i.e. no multipath), the - DetNet stream can be interrupted and result in outages. + For a single path scenario, disruption is a real possibility, whereas + in a multipath scenario, large delays or instabilities in one stream + can lead to increased buffer and CPU resources on the elimination + bridge. 4.1.2. Control Plane Delay Attacks - In and of itself, this is not directly a threat, the effects of - delaying control messages can have quite adverse effects later. - - Delayed messages for tear-down can lead to resource leakage if a - stream is not torn down at the correct time. This can in turn result - in failure to allocate new streams giving rise to a denial of service - attack. - - In the case where an End-point should be added to a multicast, - failure to deliver said signalling message will prevent the new EP - from receiving expected frames. + In and of itself, this is not directly a threat to the DetNet + service, but the effects of delaying control messages can have quite + adverse effects later. - Likewise, when an EP should be removed from a multicast group, - delaying such messages can lead to loss of privacy as the EP will - continue to receive messages even after it is removed. + o Delayed tear-down can lead to resource leakage, which in turn can + result in failure to allocate new streams finally giving rise to a + denial of service attack. -4.2. Flow Identification and Spoofing + o Failure to deliver, or severely delaying, signalling messages + adding an end-point to a multicast-group will prevent the new EP + from receiving expected frames thus disrupting expected behavior. -4.2.1. Flow identification + 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 + is supposedly removed. - 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 - going through the network and use the knowledge gathered in this - phase to mount future attacks. +4.2. Flow Modification and Spoofing - The attacker can, at their leisure, observe over time all aspects of - the messaging and signalling, learning the intent and purpose of all - traffic flows. At some later date, possibly at an important time in - an operational context, the attacker can launch a multi-faceted - attack, possibly in conjunction with some demand for ransom. +4.2.1. Flow Modification - The flow-id in the header of the data plane-messages gives an - attacker a very reliable identifier for DetNet traffic, and this - traffic has a high probability of going to lucrative targets. + ToDo. 4.2.2. Spoofing 4.2.2.1. Dataplane Spoofing Spoofing dataplane messages can result in increased resource consumptions on the bridges throughout the network as it will increase buffer usage and CPU utilization. This can lead to resource exhaustion and/or increased delay. @@ -519,154 +635,110 @@ can be forwarded through the network, using part of the allocated bandwidth. This in turn can cause legitimate messages to be dropped when the budget has been exhausted. Finally, the endpoint will have to deal with invalid messages being delivered to the endpoint instead of (or in addition to) a valid message. 4.2.2.2. Control Plane Spoofing - A successful control plane spoofing-attack has a very large - potential. It can do anything from modifying existing streams by - changing the available bandwidth, add or remove endpoints or drop the - stream altogether. It would also be possible to falsely create new - streams, which could give an attacker the ability to exhaust the - systems resources, or just enable a high quality DetNet stream - outside the Network engineer's control. + A successful control plane spoofing-attack will potentionally have + adverse effects. It can do virtually anything from: + + o modifying existing streams by changing the available bandwidth + + o add or remove endpoints from a stream + + o drop streams completly + + o falsely create new streams (exhaust the systems resources, or to + enable streams outside the Network engineer's control) 4.3. Segmentation attacks (injection) 4.3.1. Data Plane Segmentation Injection of false messages in a DetNet stream could lead to exhaustion of the available bandwidth for a stream if the bridges accounts false messages to the stream's budget. - In a multipath scenario, injected messages will cause an increased - CPU utilization on elimination bridges and if enough paths are - subject to malicious injection, the legitimate messages could be - dropped. Likewise it can cause an increase in buffer usage. In - total, this will consume more resources on the bridges than normal, - giving rise to a potential resource exhaustion attack on the bridges. + In a multipath scenario, injected messages will cause increased CPU + utilization in elimination bridges. If enough paths are subject to + malicious injection, the legitimate messages can be dropped. + Likewise it can cause an increase in buffer usage. In total, it will + consume more resources in the bridges than normal, giving rise to a + resource exhaustion attack on the bridges. If a stream is interrupted, the end application will be affected by what is now a non-deterministic stream. 4.3.2. Control Plane segmentation - A successful Control Plane segmentation attack will cause control - messages to be interpreted by nodes in the network. This has the - potential to create new streams (exhausting resources), drop existing - (denial of service), add/remove end-stations to a multicast group - (loss of privacy) or modify the stream attributes (reducing available - bandwidth, or increasing it so that new streams cannot reserve a - path). + A successful Control Plane segmentation attack control messages to be + interpreted by nodes in the network, unbeknownst to the central + controller or the network engineer. This has the potential to create - In short, this means that you cannot trust the stream reservation - properties or the network itself. + o new streams (exhausting resources) - As with spoofing, if an attacker is able to inject control-plane - messages and the receiving end does not detect it, the receiving - station must be able to. + o drop existing (denial of service) + + o add/remove end-stations to a multicast group (loss of privacy) + + o modify the stream attributes (affecting available bandwidth 4.4. Replication and Elimination The Replication and Elimination is relevant only to Data Plane messages as Signalling is not subject to multipath routing. 4.4.1. Increased Attack Surface Covered briefly in Section 4.3 4.4.2. Header Manipulation at Elimination Bridges Covered briefly in Section 4.3 -4.5. Impact of Attacks to Path Choice +4.5. Control or Signaling Packet Modification - This is covered in part in Section 4.3, and as with Replication and - Elimination (Section 4.4, this is relevant for DataPlane messages. + ToDo. -4.6. Impact of Attacks by Use Case Industry +4.6. Control or Signaling Packet Injection - This section rates the severity of various components of the impact - of a successful vulnerability exploit to use cases by industry as - described in [I-D.ietf-detnet-use-cases], including Pro Audio, - Electrical Utilities, Building Automation, Wireless for Industrial, - Cellular Radio, and Industrial M2M (split into two areas, M2M Data - Gathering and M2M Control Loop). + ToDo. - Components of Impact (left column) include Criticality of Failure, - Effects of Failure, Recovery, and DetNet Functional Dependence. - Criticality of failure summarizes the seriousness of the impact. The - impact of a resulting failure can affect many different metrics that - vary greatly in scope and severity. In order to reduce the number of - variables, the following were included: Financial, Health and Safety, - People well being, Affect on a single organization, and affect on - multiple organizations. Recovery outlines how long it would take for - an affected use case to get back to its pre-failure state (Recovery - time objective, RTO), and how much of the original service would be - lost in between the time of service failure and recovery to original - state (Recovery Point Objective, RPO). DetNET dependence maps how - much the following DetNet service objectives contribute to impact of - failure: Time dependency, data integrity, source node integrity, - availability, latency/jitter. +4.7. Reconnaissance - The scale of the Impact mappings is low, medium, and high. In some - use cases there may be a multitude of specific applications in which - DetNET is used. For simplicity this section attempts to average the - varied impacts of different applications. This section does not - address the overall risk of a certain impact which would require the - likelihood of a failure happening. + 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 + going through the network and use the knowledge gathered in this + phase to mount future attacks. - In practice any such ratings will vary from case to case; the ratings - shown here are given as examples. + The attacker can, at their leisure, observe over time all aspects of + the messaging and signalling, learning the intent and purpose of all + traffic flows. At some later date, possibly at an important time in + an operational context, the attacker can launch a multi-faceted + attack, possibly in conjunction with some demand for ransom. - +------------------+-----------------------------------------+-----+ - | | Pro A | Util | Bldg |Wire- | Cell |M2M |M2M | - | | | | | less | |Data |Ctrl | - +------------------+-----------------------------------------+-----+ - | Criticality | Med | Hi | Low | Med | Med | Med | Med | - +------------------+-----------------------------------------+-----+ - | Effects - +------------------+-----------------------------------------+-----+ - | Financial | Med | Hi | Med | Med | Low | Med | Med | - +------------------+-----------------------------------------+-----+ - | Health/Safety | Med | Hi | Hi | Med | Med | Med | Med | - +------------------+-----------------------------------------+-----+ - | People WB | Med | Hi | Hi | Low | Hi | Low | Low | - +------------------+-----------------------------------------+-----+ - | Effect 1 org | Hi | Hi | Med | Hi | Med | Med | Med | - +------------------+-----------------------------------------+-----+ - | Effect >1 org | Med | Hi | Low | Med | Med | Med | Med | - +------------------+-----------------------------------------+-----+ - |Recovery - +------------------+-----------------------------------------+-----+ - | Recov Time Obj | Med | Hi | Med | Hi | Hi | Hi | Hi | - +------------------+-----------------------------------------+-----+ - | Recov Point Obj | Med | Hi | Low | Med | Low | Hi | Hi | - +------------------+-----------------------------------------+-----+ - |DetNet Dependence - +------------------+-----------------------------------------+-----+ - | Time Dependency | Hi | Hi | Low | Hi | Med | Low | Hi | - +------------------+-----------------------------------------+-----+ - | Latency/Jitter | Hi | Hi | Med | Med | Low | Low | Hi | - +------------------+-----------------------------------------+-----+ - | Data Integrity | Hi | Hi | Med | Hi | Low | Hi | Low | - +------------------+-----------------------------------------+-----+ - | Src Node Integ | Hi | Hi | Med | Hi | Med | Hi | Hi | - +------------------+-----------------------------------------+-----+ - | Availability | Hi | Hi | Med | Hi | Low | Hi | Hi | - +------------------+-----------------------------------------+-----+ + The flow-id in the header of the data plane-messages gives an + attacker a very reliable identifier for DetNet traffic, and this + traffic has a high probability of going to lucrative targets. - Figure 2: Impact of Attacks by Use Case Industry +4.8. Attacks on Time Sync Mechanisms + + ToDo. + +4.9. Attacks on Path Choice + + This is covered in part in Section 4.3, and as with Replication and + Elimination (Section 4.4, this is relevant for DataPlane messages. 5. Security Threat Mitigation This section describes a set of measures that can be taken to mitigate the attacks described in Section 3. These mitigations should be viewed as a toolset that includes several different and diverse tools. Each application or system will typically use a subset of these tools, based on a system-specific threat analysis. 5.1. Path Redundancy @@ -772,20 +845,23 @@ +----------------------+---------------------+---------------------+ | Attack | Impact | Mitigations | +----------------------+---------------------+---------------------+ |Delay Attack |-Non-deterministic |-Path redundancy | | | delay |-Performance | | |-Data disruption | analytics | | |-Increased resource | | | | consumption | | +----------------------+---------------------+---------------------+ + |Reconnaissance |-Enabler for other |-Encryption | + | | attacks | | + +----------------------+---------------------+---------------------+ |DetNet Flow Modificat-|-Increased resource |-Path redundancy | |ion or Spoofing | consumption |-Integrity protection| | |-Data disruption |-DetNet Node | | | | authentication | +----------------------+---------------------+---------------------+ |Inter-Segment Attack |-Increased resource |-Path redundancy | | | consumption |-Performance | | |-Data disruption | analytics | +----------------------+---------------------+---------------------+ |Replication: Increased|-All impacts of other|-Integrity protection| @@ -807,268 +883,432 @@ | |-Non-deterministic | | | | delay | | | |-Data disruption | | +----------------------+---------------------+---------------------+ |Control or Signaling |-Increased resource |-Control message | |Packet Injection | consumption | protection | | |-Non-deterministic | | | | delay | | | |-Data disruption | | +----------------------+---------------------+---------------------+ - |Reconnaissance |-Enabler for other |-Encryption | - | | attacks | | - +----------------------+---------------------+---------------------+ |Attacks on Time Sync |-Non-deterministic |-Path redundancy | |Mechanisms | delay |-Control message | | |-Increased resource | protection | | | consumption |-Performance | | |-Data disruption | analytics | +----------------------+---------------------+---------------------+ Figure 3: Mapping Attacks to Impact and Mitigations 6. Association of Attacks to Use Cases -6.1. Use Cases by Common Themes - Different attacks can have different impact and/or mitigation depending on the use case, so we would like to make this association in our analysis. However since there is a potentially unbounded list 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 section of the DetNet Use Cases draft [I-D.ietf-detnet-use-cases]. - We describe each theme and its associated attacks, impacts and - mitigations. + + See also Figure 2 for a mapping of the impact of attacks per use case + by industry. + +6.1. Use Cases by Common Themes + + In this section we review each theme and discuss the attacks that are + applicable to that theme, as well as anything specific about the + impact and mitigations for that attack with respect to that theme. + The table Figure 5 then provides a summary of the attacks that are + applicable to each theme. 6.1.1. Network Layer - AVB/TSN Ethernet - Presumably it will be possible to run DetNet over other underlying - network layers besides Ethernet, but Ethernet is explicitly - supported. Is the attack specific to the Ethernet AVB/TSN protocols? - Does the threat affect only Ethernet, or any underlying network - layer? + DetNet is expected to run over various transmission mediums, with + Ethernet being explicitly supported. Attacks such as Delay or + Reconnaissance might be implemented differently on a different + transmission medium, however the impact on the DetNet as a whole + would be essentially the same. We thus conclude that all attacks and + impacts that would be applicable to DetNet over Ethernet (i.e. all + those named in this draft) would also be applicable to DetNet over + other transmission mediums. + + With respect to mitigations, some methods are specific to the + Ethernet medium, for example time-aware scheduling using 802.1Qbv can + protect against excessive use of bandwidth at the ingress - for other + mediums, other mitigations would have to be implemented to provide + analogous protection. 6.1.2. Central Administration A DetNet network is expected to be controlled by a centralized - network configuration and control system. Such a system may be in a - single central location, or it may be distributed across multiple - control entities that function together as a unified control system - for the network. Is the attack directed at threat the central - control system of the network? Does it interfere with OAM? + network configuration and control system (CNC). Such a system may be + in a single central location, or it may be distributed across + multiple control entities that function together as a unified control + system for the network. + + In this draft we distinguish between attacks on the DetNet Control + plane vs. Data plane. But is an attack affecting control plane + 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 + scope, and consider all attacks named in this draft which are + relevant to control plane packets to be relevant to this theme, + including Path Manipulation, Path Choice, Control Packet Modification + or Injection, Reconaissance and Attacks on Time Sync Mechanisms. 6.1.3. Hot Swap A DetNet network is not expected to be "plug and play" - it is expected that there is some centralized network configuration and control system. However, the ability to "hot swap" components (e.g. due to malfunction) is similar enough to "plug and play" that this kind of behavior may be expected in DetNet networks, depending on the - implementation. Does the attack target "hot swap" ("plug and play") - operation in the network? + implementation. + + An attack surface related to Hot Swap is that the DetNet network must + at least consider input at runtime from devices that were not part of + the initial configuration of the network. Even a "perfect" (or + "hitless") replacement of a device at runtime would not necessarily + be ideal, since presumably one would want to distinguish it from the + original for OAM purposes (e.g. to report hot swap of a failed + device). + + This implies that an attack such as Flow Modification, Spoofing or + Inter-segment (which could introduce packets from a "new" device + (i.e. one heretofore unknown on the network) could be used to exploit + the need to consider such packets (as opposed to rejecting them out + of hand as one would do if one did not have to consider introduction + of a new device). + + Similarly if the network was designed to support runtime replacement + of a clock device, then presence (or apparent presence) and thus + consideration of packets from a new such device could affect the + network, or the time sync of the network, for example by initiating a + new Best Master Clock selection process. Thus attacks on time sync + should be considered when designing hot swap type functionality. 6.1.4. Data Flow Information Models Data Flow Information Models specific to DetNet networks are to be specified by DetNet. Thus they are "new" and thus potentially present a new attack surface. Does the threat take advantage of any aspect of our new Data Flow Info Models? + This is TBD, thus there are no specific entries in our table, however + that does not imply that there could be no relevant attacks. + 6.1.5. L2 and L3 Integration - A DetNet network is intended to integrate between Layer 2 (bridged) - network(s) (e.g. AVB/TSN LAN) and Layer 3 (routed) network(s) (e.g. - using IP-based protocols). Does the attack target L2? L3? Both? - The interaction between the two? + A DetNet network integrates Layer 2 (bridged) networks (e.g. AVB/TSN + LAN) and Layer 3 (routed) networks via the use of well-known + protocols such as IPv6, MPLS-PW, and Ethernet. Presumably security + 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 + that does not imply that there could be no relevant attacks. 6.1.6. End-to-End Delivery Packets sent over DetNet are guaranteed not to be dropped by the network due to congestion. (Packets may however be dropped for - intended reasons, e.g. per security measures). Does the attack - result in packets (which should be delivered) not being delivered? - Does it result in packets that should not be delivered being - delivered? + intended reasons, e.g. per security measures). + + A Data plane attack may force packets to be dropped, for example a + "long" Delay or Replication/Elimination or Flow Modification attack. + + The same result might be obtained by a Control plane attack, e.g. + Path Manipulation or Signaling Packet Modification. + + It may be that such attacks are limited to Internal MITM attackers, + but other possibilities should be considered. + + 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 + to be preferred over another path when they should not be + (Replication attack), or by Flow Modification, or by Path Choice or + Packet Injection. A Time Sync attack could cause a system that was + expecting certain packets at certain times to accept unintended + packets based on compromised system time or time windowing in the + scheduler. 6.1.7. Proprietary Deterministic Ethernet Networks There are many proprietary non-interoperable deterministic Ethernet- based networks currently available; DetNet is intended to provide an - open-standards-based alternative to such networks. Does the threat - relate to a specific such network that is being "emulated" or - "replaced" by DetNet, for example by exploiting specific commands - specific to that network protocol? + open-standards-based alternative to such networks. In cases where a + DetNet intersects with remnants of such networks or their protocols, + such as by protocol emulation or access to such a network via a + gateway, new attack surfaces can be opened. + + For example an Inter-Segment or Control plane attack such as Path + Manipulation, Path Choice or Control Packet Modification/Injection + could be used to exploit commands specific to such a protocol, or + that are interpreted differently by the different protocols or + gateway. 6.1.8. Replacement for Proprietary Fieldbuses There are many proprietary "field buses" used in today's industrial and other industries; DetNet is intended to provide an open- - standards-based alternative to such buses. Does the threat relate to - a specific fieldbus that is being "emulated" or "replaced" by DetNet, - for example by exploiting specific commands specific to that network - protocol? + standards-based alternative to such buses. In cases where a DetNet + intersects with such fieldbuses or their protocols, such as by + protocol emulation or access via a gateway, new attack surfaces can + be opened. + + For example an Inter-Segment or Control plane attack such as Path + Manipulation, Path Choice or Control Packet Modification/Injection + could be used to exploit commands specific to such a protocol, or + that are interpreted differently by the different protocols or + gateway. 6.1.9. Deterministic vs Best-Effort Traffic DetNet is intended to support coexistence of time-sensitive operational (OT, deterministic) traffic and information (IT, "best - effort") traffic on the same ("unified") network. Does the attack - affect only IT or only OT or both types of traffic? Does the threat - affect any interaction between IT and OT traffic, e.g. by changing - relative priority or handling of IT vs. OT packets? + effort") traffic on the same ("unified") network. + + The presence of IT traffic on a network carrying OT traffic has long + been considered insecure design [reference needed here]. With + DetNet, this coexistance will become more common, and mitigations + will need to be established. The fact that the IT traffic on a + DetNet is limited to a corporate controlled network makes this a less + difficult problem compared to being exposed to the open Internet, + however this aspect of DetNet security should not be underestimated. + + Most of the themes described in this draft address OT (reserved) + streams - this item is intended to address issues related to IT + traffic on a DetNet. + + 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 + of interfering with OT traffic. Presumably if the stream reservation + and isolation of the DetNet is well-designed (better-designed than + the attack) then interference with OT traffic should not result from + an attack that floods the network with IT traffic. + + However the DetNet's handling of IT traffic may not (by design) be as + resilient to DOS attack, and thus designers must be otherwise + prepared to mitigate DOS attacks on IT traffic in a DetNet. 6.1.10. Deterministic Flows - Reserved bandwidth data flows (deterministic flows) must be isolated - from each other and from best-effort traffic, so that even if the - network is saturated with best-effort and/or reserved bandwidth - traffic the configured flows are not adversely affected. Does the - attack affect the isolation of one (reserved) flow from another? + Reserved bandwidth data flows (deterministic flows) must provide the + allocated bandwidth, and must be isolated from each other. + + A Spoofing or Inter-segment attack which adds packet traffic to a + bandwidth-reserved stream could cause that stream to occupy more + bandwidth than it is allocated, resulting in interference with other + deterministic flows. + + A Flow Modification or Spoofing or Header Manipulation or Control + Packet Modification attack could cause packets from one flow to be + directed to another flow, thus breaching isolation between the flows. 6.1.11. Unused Reserved Bandwidth If bandwidth reservations are made for a stream but the associated bandwidth is not used at any point in time, that bandwidth is made available on the network for best-effort traffic. If the owner of the reserved stream then starts transmitting again, the bandwidth is no longer available for best-effort traffic, on a moment-to-moment basis. (Such "temporarily available" bandwidth is not available for - time-sensitive traffic, which must have its own reservation). Does - the attack affect the system's ability to allocate unused reserved BW - to best-effort traffic? + time-sensitive traffic, which must have its own reservation). + + An Inter-segment attack could flood the network with IT traffic, + interfering with the intended IT traffic. + + A Flow Modification or Spoofing or Control Packet Modification or + Injection attack could cause extra bandwidth to be reserved by a new + or existing stream, thus making it unavailable for use by best-effort + traffic. 6.1.12. Interoperability The DetNet network specifications are intended to enable an ecosystem in which multiple vendors can create interoperable products, thus promoting device diversity and potentially higher numbers of each device manufactured. Does the threat take advantage of differences in implementation of "interoperable" products made by different vendors? + This is TBD, thus there are no specific entries in our table, however + that does not imply that there could be no relevant attacks. + 6.1.13. Cost Reductions The DetNet network specifications are intended to enable an ecosystem in which multiple vendors can create interoperable products, thus promoting higher numbers of each device manufactured, promoting cost reduction and cost competition among vendors. Does the threat take advantage of "low cost" HW or SW components or other "cost-related shortcuts" that might be present in devices? + This is TBD, thus there are no specific entries in our table, however + that does not imply that there could be no relevant attacks. + 6.1.14. Insufficiently Secure Devices The DetNet network specifications are intended to enable an ecosystem in which multiple vendors can create interoperable products, thus promoting device diversity and potentially higher numbers of each device manufactured. Does the threat attack "naivete" of SW, for example SW that was not designed to be sufficiently secure (or secure at all) but is deployed on a DetNet network that is intended to be highly secure? (For example IoT exploits like the Mirai video-camera botnet ([MIRAI]). + This is TBD, thus there are no specific entries in our table, however + that does not imply that there could be no relevant attacks. + 6.1.15. DetNet Network Size DetNet networks range in size from very small, e.g. inside a single industrial machine, to very large, for example a Utility Grid network - spanning a whole country, and involving many "hops" over various - kinds of links for example radio repeaters, microwave links, fiber - optic links, etc.. Does the attack affect DetNet networks of only - certain sizes, e.g. very large networks, or very small? This might - be related to how the attack is introduced into the network, for - example if the entire network is local, there is a threat that power - can be cut to the entire network. If the network is large, perhaps - only a part of the network is attacked. Does the threat take - advantage of attack vectors that are specific to network size? + spanning a whole country. + + The size of the network might be related to how the attack is + introduced into the network, for example if the entire network is + local, there is a threat that power can be cut to the entire network. + If the network is large, perhaps only a part of the network is + attacked. + + A Delay attack might be as relevant to a small network as to a large + network, although the amount of delay might be different. + + Attacks sourced from IT traffic might be more likely in large + networks, since more people might have access to the network. + Similarly Path Manipulation, Path Choice and Time Sync attacks seem + more likely relevant to large networks. 6.1.16. Multiple Hops - DetNet networks range in size from very small, e.g. inside a single - industrial machine, to very large, for example a Utility Grid network - spanning a whole country, and involving many "hops" over various - kinds of links for example radio repeaters, microwave links, fiber - optic links, etc.. Does the attack exploit the presence of more than - one "hop"? Does the threat exploit the presence of more than one - type of "hop", e.g. between radio and microwave links? Does the - threat exploit a specific type of "hop", e.g. something specific to - a fiber optic link, or other type of link? + Large DetNet networks (e.g. a Utility Grid network) may involve many + "hops" over various kinds of links for example radio repeaters, + microwave links, fiber optic links, etc.. + + An attack that takes advantage of flaws (or even normal operation) in + the device drivers for the various links (through internal knowledge + of how the individual driver or firmware operates, perhaps like the + Stuxnet attack) could take proportionately greater advantage of this + topology. We don't currently have an attack like this defined; we + have only "protocol" (time or packet) based attacks. Perhaps we need + to define an attack like this? Or is that out of scope for DetNet? + + It is also possible that this DetNet topology will not be in as + common use as other more homogeneous topologies so there may be more + opportunity for attackers to exploit software and/or protocol flaws + in the implementations which have not been wrung out by extensive + use, particularly in the case of early adopters. + + Of the attacks we have defined, the ones identified above as relevant + to "large" networks seem to be most relevant. 6.1.17. Level of Service A DetNet is expected to provide means to configure the network that include querying network path latency, requesting bounded latency for a given stream, requesting worst case maximum and/or minimum latency for a given path or stream, and so on. It is an expected case that the network cannot provide a given requested service level. In such cases the network control system should reply that the requested service level is not available (as opposed to accepting the parameter - but then not delivering the desired behavior). Does the attack - affect any querying or replying to such service-level-related - traffic? Can the attack cause incorrect responses from the system - regarding timing-related configuration? For example replying that a - requested level of service is available when it isn't, or that the - requested level of service is not available when it actually is - available? + but then not delivering the desired behavior). + + Control plane attacks such as Signaling Packet Modification and + Injection could be used to modify or create control traffic that + could interfere with the process of a user requesting a level of + service and/or the network's reply. + + Reconnaissance could be used to characterize flows and perhaps target + specific flows for attack via the Control plane as noted above. 6.1.18. Bounded Latency - Does the threat affect the network's ability to deliver packets - within the agreed-upon latency boundaries? + DetNet provides the expectation of guaranteed bounded latency. + + Delay attacks can cause packets to miss their agreed-upon latency + boundaries. + + Time Sync attacks can corrupt the system's time reference, resulting + in missed latency deadlines (with respect to the "correct" time + reference). 6.1.19. Low Latency Applications may require "extremely low latency" however depending on the application these may mean very different latency values; for example "low latency" across a Utility grid network is on a different time scale than "low latency" in a motor control loop in a small machine. The intent is that the mechanisms for specifying desired latency include wide ranges, and that architecturally there is nothing to prevent arbitrarily low latencies from being implemented - in a given network. Does the threat affect the network's ability to - deliver packets within the agreed-upon low latency? + in a given network. + + Attacks on the Control plane (as described in the Level of Service + theme) and Delay and Time attacks (as described in the Bounded + Latency theme) both apply here. 6.1.20. Symmetrical Path Delays Some applications would like to specify that the transit delay time - values be equal for both the transmit and return paths. Does the - attack affect the network's ability to provide matched transmit and - return path delays (latencies)? + values be equal for both the transmit and return paths. + + Delay attacks can cause path delays to differ. + + Time Sync attacks can corrupt the system's time reference, resulting + in differing path delays (with respect to the "correct" time + reference). 6.1.21. Reliability and Availability DetNet based systems are expected to be implemented with essentially arbitrarily high availability (for example 99.9999% up time, or even 12 nines). The intent is that the DetNet designs should not make any assumptions about the level of reliability and availability that may be required of a given system, and should define parameters for - communicating these kinds of metrics within the network. Does the - attack affect the reliability of the DetNet network? Is it a large - or small change, e.g. the difference between completely taking down - the network for some period of time, vs reducing its reliability by - just one "nine"? Does the threat affect the availability of the - DetNet network? + communicating these kinds of metrics within the network. + + Any attack on the system, of any type, can affect its overall + reliability and availability, thus in our table we have marked every + attack. Since every DetNet depends to a greater or lesser degree on + reliability and availability, this essentially means that all + networks have to mitigate all attacks, which to a greater or lesser + degree defeats the purpose of associating attacks with use cases. It + also underscores the difficulty of designing "extremely high + reliability" networks. I hope that in future drafts we can say + something more useful here. 6.1.22. Redundant Paths DetNet based systems are expected to be implemented with essentially arbitrarily high reliability/availability. A strategy used by DetNet for providing such extraordinarily high levels of reliability is to provide redundant paths that can be seamlessly switched between, all - the while maintaining the required performance of that system. Does - the attack affect the configuration or operation of redundant paths? + the while maintaining the required performance of that system. + + Replication-related attacks are by definition applicable here. + Control plane attacks can also interfere with the configuration of + redundant paths. 6.1.23. Security Measures A DetNet network must be made secure against devices failures, attackers, misbehaving devices, and so on. Does the threat affect such security measures themselves, e.g. by attacking SW designed to protect against device failure? + This is TBD, thus there are no specific entries in our table, however + that does not imply that there could be no relevant attacks. + 6.2. Attack Types by Use Case Common Theme The following table lists the attacks of Section 3, assigning a number to each type of attack. That number is then used as a short form identifier for the attack in Figure 5. +--+----------------------------------------+----------------------+ | | Attack | Section | +--+----------------------------------------+----------------------+ | 1|Delay Attack | Section 3.2.1 | @@ -1106,53 +1346,53 @@ | | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Network Layer - AVB/TSN Eth.| +| +| +| +| +| +| +| +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Central Administration | | | | | | +| +| +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Hot Swap | | +| +| | | | | | | | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Data Flow Information Models| | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ - |L2 and L3 Integration | | | | | +| +| | | | | | + |L2 and L3 Integration | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ - |End-to-end Delivery | | | | +| +| | | | | | | + |End-to-end Delivery | +| +| +| +| +| +| +| +| +| | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Proprietary Deterministic | | | +| | | +| +| +| +| | | |Ethernet Networks | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Replacement for Proprietary | | | +| | | +| +| +| +| | | |Fieldbuses | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Deterministic vs. Best- | | | +| | | | | | | | | |Effort Traffic | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ - |Deterministic Flows | | | +| | | | | | | | | + |Deterministic Flows | | +| +| | +| +| | +| | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ - |Unused Reserved Bandwidth | | | +| | | | | | | | | + |Unused Reserved Bandwidth | | +| +| | | | | +| +| | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Interoperability | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Cost Reductions | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Insufficiently Secure | | | | | | | | | | | | |Devices | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |DetNet Network Size | +| | | | | +| +| | | | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Multiple Hops | +| +| | | | +| +| | | | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Level of Service | | | | | | | | +| +| +| | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Bounded Latency | +| | | | | | | | | | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ - |Low Latency | +| | | | | | | | | | +| + |Low Latency | +| | | | | | | +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Symmetric Path Delays | +| | | | | | | | | | +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Reliability and Availability| +| +| +| +| +| +| +| +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Redundant Paths | | | | +| +| | | +| +| | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Security Measures | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ @@ -1478,38 +1718,44 @@ [I-D.ietf-detnet-architecture] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", draft-ietf- detnet-architecture-03 (work in progress), August 2017. [I-D.ietf-detnet-use-cases] Grossman, E., Gunther, C., Thubert, P., Wetterwald, P., Raymond, J., Korhonen, J., Kaneko, Y., Das, S., Zha, Y., Varga, B., Farkas, J., Goetz, F., Schmitt, J., Vilajosana, - X., Mahmoodi, T., Spirou, S., and P. Vizarreta, - "Deterministic Networking Use Cases", draft-ietf-detnet- - use-cases-12 (work in progress), April 2017. + X., Mahmoodi, T., Spirou, S., Vizarreta, P., Huang, D., + Geng, X., Dujovne, D., and M. Seewald, "Deterministic + Networking Use Cases", draft-ietf-detnet-use-cases-13 + (work in progress), September 2017. [I-D.varga-detnet-service-model] Varga, B. and J. Farkas, "DetNet Service Model", draft- varga-detnet-service-model-02 (work in progress), May 2017. [IEEE1588] IEEE, "IEEE 1588 Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems Version 2", 2008. [MIRAI] krebsonsecurity.com, "https://krebsonsecurity.com/2016/10/ hacked-cameras-dvrs-powered-todays-massive-internet- outage/", 2016. + [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC + Text on Security Considerations", BCP 72, RFC 3552, + DOI 10.17487/RFC3552, July 2003, + . + [RFC7384] Mizrahi, T., "Security Requirements of Time Protocols in Packet Switched Networks", RFC 7384, DOI 10.17487/RFC7384, October 2014, . Authors' Addresses Tal Mizrahi Marvell Email: talmi@marvell.com