--- 1/draft-ietf-detnet-security-10.txt 2020-08-14 20:13:17.323897211 -0700 +++ 2/draft-ietf-detnet-security-11.txt 2020-08-14 20:13:17.439900162 -0700 @@ -1,126 +1,102 @@ Internet Engineering Task Force T. Mizrahi Internet-Draft HUAWEI Intended status: Informational E. Grossman, Ed. -Expires: December 1, 2020 DOLBY - May 30, 2020 +Expires: February 15, 2021 DOLBY + August 14, 2020 Deterministic Networking (DetNet) Security Considerations - draft-ietf-detnet-security-10 + draft-ietf-detnet-security-11 Abstract A DetNet (deterministic network) provides specific performance guarantees to its data flows, such as extremely low data loss rates - and bounded latency. As a result, securing a DetNet implies that in + and bounded latency. As a result, securing a DetNet requires that in addition to the best practice security measures taken for any mission-critical network, additional security measures may be needed - whose purpose is exclusively to secure the intended operation of - these novel service properties. - - Designers of DetNet components (such as routers) that provide these - unique DetNet properties have the responsibility to uphold certain - security-related properties that can be assumed by DetNet system- - level designers. For example, the assumption that network traffic - associated with a given flow can never affect traffic associated with - a different flow is only true if the underlying components make it - so. + to secure the intended operation of these novel service properties. This document addresses DetNet-specific security considerations from - the perspective of both the DetNet component designer and the DetNet - system-level designer. It is assumed that both classes of reader are - already familiar with network security best practices for the data - plane technologies underlying a given DetNet implementation. - Component-level considerations include isolation of data flows from - each other, ingress filtering, and detection and reporting of packet - arrival time violations. System-level considerations include a - threat model and a taxonomy of relevant attacks, including their - potential impacts and mitigations. - - A given DetNet may require securing only certain aspects of DetNet - performance, for example extremely low data loss rates but not - necessarily bounded latency. Therefore this document provides an - association of threats against various use cases by industry, and - also against the individual service properties as defined in the - DetNet Use Cases. - - This document also addresses common DetNet security considerations - related to the IP and MPLS data plane technologies (the first to be - identified as supported by DetNet), thereby complementing the + the perspectives of both the DetNet system-level designer and + component designer. System considerations include a threat model, + taxonomy of relevant attacks, and associations of threats versus use + cases and service properties. Component-level considerations include + ingress filtering and packet arrival time violation detection. This + document also addresses DetNet security considerations specific to + the IP and MPLS data plane technologies thereby complementing the Security Considerations sections of the various DetNet Data Plane (and other) DetNet documents. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at 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 December 1, 2020. + This Internet-Draft will expire on February 15, 2021. Copyright Notice Copyright (c) 2020 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . 6 - 3. Security Considerations for DetNet Component Design . . . . . 7 + 2. Abbreviations and Terminology . . . . . . . . . . . . . . . . 6 + 3. Security Considerations for DetNet Component Design . . . . . 6 3.1. Resource Allocation . . . . . . . . . . . . . . . . . . . 7 3.2. Explicit Routes . . . . . . . . . . . . . . . . . . . . . 7 - 3.3. Redundant Path Support . . . . . . . . . . . . . . . . . 8 - 3.4. Timing Violation Reporting . . . . . . . . . . . . . . . 9 + 3.3. Redundant Path Support . . . . . . . . . . . . . . . . . 7 + 3.4. Timing (or other) Violation Reporting . . . . . . . . . . 8 4. DetNet Security Considerations Compared With DiffServ Security Considerations . . . . . . . . . . . . . . . . . . . 9 5. Security Threats . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 10 5.2. Threat Analysis . . . . . . . . . . . . . . . . . . . . . 11 5.2.1. Delay . . . . . . . . . . . . . . . . . . . . . . . . 11 - 5.2.1.1. Delay Attack . . . . . . . . . . . . . . . . . . 11 5.2.2. DetNet Flow Modification or Spoofing . . . . . . . . 11 - 5.2.3. Resource Segmentation or Slicing . . . . . . . . . . 11 - 5.2.3.1. Inter-segment Attack . . . . . . . . . . . . . . 11 + 5.2.3. Resource Segmentation (Inter-segment Attack) . . . . 12 5.2.4. Packet Replication and Elimination . . . . . . . . . 12 5.2.4.1. Replication: Increased Attack Surface . . . . . . 12 5.2.4.2. Replication-related Header Manipulation . . . . . 12 - 5.2.5. Path Choice . . . . . . . . . . . . . . . . . . . . . 12 - 5.2.5.1. Path Manipulation . . . . . . . . . . . . . . . . 12 + 5.2.5. Path Choice . . . . . . . . . . . . . . . . . . . . . 13 + 5.2.5.1. Path Manipulation . . . . . . . . . . . . . . . . 13 5.2.5.2. Path Choice: Increased Attack Surface . . . . . . 13 5.2.6. Controller Plane . . . . . . . . . . . . . . . . . . 13 5.2.6.1. Control or Signaling Packet Modification . . . . 13 5.2.6.2. Control or Signaling Packet Injection . . . . . . 13 5.2.7. Scheduling or Shaping . . . . . . . . . . . . . . . . 13 5.2.7.1. Reconnaissance . . . . . . . . . . . . . . . . . 13 5.2.8. Time Synchronization Mechanisms . . . . . . . . . . . 13 - 5.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 13 + 5.3. Threat Summary . . . . . . . . . . . . . . . . . . . . . 14 6. Security Threat Impacts . . . . . . . . . . . . . . . . . . . 14 6.1. Delay-Attacks . . . . . . . . . . . . . . . . . . . . . . 17 6.1.1. Data Plane Delay Attacks . . . . . . . . . . . . . . 17 6.1.2. Controller Plane Delay Attacks . . . . . . . . . . . 18 6.2. Flow Modification and Spoofing . . . . . . . . . . . . . 18 6.2.1. Flow Modification . . . . . . . . . . . . . . . . . . 18 6.2.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . 18 6.2.2.1. Dataplane Spoofing . . . . . . . . . . . . . . . 18 6.2.2.2. Controller Plane Spoofing . . . . . . . . . . . . 19 6.3. Segmentation Attacks (injection) . . . . . . . . . . . . 19 @@ -129,80 +105,80 @@ 6.4. Replication and Elimination . . . . . . . . . . . . . . . 20 6.4.1. Increased Attack Surface . . . . . . . . . . . . . . 20 6.4.2. Header Manipulation at Elimination Routers . . . . . 20 6.5. Control or Signaling Packet Modification . . . . . . . . 20 6.6. Control or Signaling Packet Injection . . . . . . . . . . 20 6.7. Reconnaissance . . . . . . . . . . . . . . . . . . . . . 20 6.8. Attacks on Time Sync Mechanisms . . . . . . . . . . . . . 21 6.9. Attacks on Path Choice . . . . . . . . . . . . . . . . . 21 7. Security Threat Mitigation . . . . . . . . . . . . . . . . . 21 7.1. Path Redundancy . . . . . . . . . . . . . . . . . . . . . 21 - 7.2. Integrity Protection . . . . . . . . . . . . . . . . . . 21 + 7.2. Integrity Protection . . . . . . . . . . . . . . . . . . 22 7.3. DetNet Node Authentication . . . . . . . . . . . . . . . 22 7.4. Dummy Traffic Insertion . . . . . . . . . . . . . . . . . 23 7.5. Encryption . . . . . . . . . . . . . . . . . . . . . . . 23 - 7.5.1. Encryption Considerations for DetNet . . . . . . . . 23 - 7.6. Control and Signaling Message Protection . . . . . . . . 24 + 7.5.1. Encryption Considerations for DetNet . . . . . . . . 24 + 7.6. Control and Signaling Message Protection . . . . . . . . 25 7.7. Dynamic Performance Analytics . . . . . . . . . . . . . . 25 - 7.8. Mitigation Summary . . . . . . . . . . . . . . . . . . . 25 + 7.8. Mitigation Summary . . . . . . . . . . . . . . . . . . . 26 8. Association of Attacks to Use Cases . . . . . . . . . . . . . 27 - 8.1. Use Cases by Common Themes . . . . . . . . . . . . . . . 27 + 8.1. Association of Attacks to Use Case Common Themes . . . . 27 8.1.1. Sub-Network Layer . . . . . . . . . . . . . . . . . . 27 8.1.2. Central Administration . . . . . . . . . . . . . . . 28 8.1.3. Hot Swap . . . . . . . . . . . . . . . . . . . . . . 28 8.1.4. Data Flow Information Models . . . . . . . . . . . . 29 8.1.5. L2 and L3 Integration . . . . . . . . . . . . . . . . 29 8.1.6. End-to-End Delivery . . . . . . . . . . . . . . . . . 29 - 8.1.7. Proprietary Deterministic Ethernet Networks . . . . . 30 - 8.1.8. Replacement for Proprietary Fieldbuses . . . . . . . 30 - 8.1.9. Deterministic vs Best-Effort Traffic . . . . . . . . 30 - 8.1.10. Deterministic Flows . . . . . . . . . . . . . . . . . 31 - 8.1.11. Unused Reserved Bandwidth . . . . . . . . . . . . . . 31 - 8.1.12. Interoperability . . . . . . . . . . . . . . . . . . 31 - 8.1.13. Cost Reductions . . . . . . . . . . . . . . . . . . . 32 - 8.1.14. Insufficiently Secure Devices . . . . . . . . . . . . 32 - 8.1.15. DetNet Network Size . . . . . . . . . . . . . . . . . 32 - 8.1.16. Multiple Hops . . . . . . . . . . . . . . . . . . . . 33 - 8.1.17. Level of Service . . . . . . . . . . . . . . . . . . 33 - 8.1.18. Bounded Latency . . . . . . . . . . . . . . . . . . . 33 - 8.1.19. Low Latency . . . . . . . . . . . . . . . . . . . . . 34 - 8.1.20. Bounded Jitter (Latency Variation) . . . . . . . . . 34 - 8.1.21. Symmetrical Path Delays . . . . . . . . . . . . . . . 34 - 8.1.22. Reliability and Availability . . . . . . . . . . . . 34 - 8.1.23. Redundant Paths . . . . . . . . . . . . . . . . . . . 35 - 8.1.24. Security Measures . . . . . . . . . . . . . . . . . . 35 - 8.2. Attack Types by Use Case Common Theme . . . . . . . . . . 35 + 8.1.7. Replacement for Proprietary Fieldbuses and Ethernet- + based Networks . . . . . . . . . . . . . . . . . . . 30 + 8.1.8. Deterministic vs Best-Effort Traffic . . . . . . . . 30 + 8.1.9. Deterministic Flows . . . . . . . . . . . . . . . . . 31 + 8.1.10. Unused Reserved Bandwidth . . . . . . . . . . . . . . 31 + 8.1.11. Interoperability . . . . . . . . . . . . . . . . . . 31 + 8.1.12. Cost Reductions . . . . . . . . . . . . . . . . . . . 31 + 8.1.13. Insufficiently Secure Devices . . . . . . . . . . . . 32 + 8.1.14. DetNet Network Size . . . . . . . . . . . . . . . . . 32 + 8.1.15. Multiple Hops . . . . . . . . . . . . . . . . . . . . 33 + 8.1.16. Level of Service . . . . . . . . . . . . . . . . . . 33 + 8.1.17. Bounded Latency . . . . . . . . . . . . . . . . . . . 33 + 8.1.18. Low Latency . . . . . . . . . . . . . . . . . . . . . 34 + 8.1.19. Bounded Jitter (Latency Variation) . . . . . . . . . 34 + 8.1.20. Symmetrical Path Delays . . . . . . . . . . . . . . . 34 + 8.1.21. Reliability and Availability . . . . . . . . . . . . 34 + 8.1.22. Redundant Paths . . . . . . . . . . . . . . . . . . . 35 + 8.1.23. Security Measures . . . . . . . . . . . . . . . . . . 35 + 8.2. Summary of Attack Types per Use Case Common Theme . . . . 35 8.3. Security Considerations for OAM Traffic . . . . . . . . . 38 9. DetNet Technology-Specific Threats . . . . . . . . . . . . . 38 9.1. IP . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 9.2. MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . 40 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 41 11. Security Considerations . . . . . . . . . . . . . . . . . . . 41 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 41 13. Informative References . . . . . . . . . . . . . . . . . . . 42 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 1. Introduction 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. + real-time Operational Technology (OT) applications for some years. However, such networks are typically isolated from external access, and thus the security threat from external attackers is low. IETF - Deterministic Networking (DetNet) specifies a set of technologies - that enable creation of deterministic networks on IP-based networks - of potentially wide area (on the scale of a corporate network) - potentially bringing the OT network into contact with Information - Technology (IT) traffic and security threats that lie outside of a - tightly controlled and bounded area (such as the internals of an - aircraft). + Deterministic Networking (DetNet, [RFC8655]) specifies a set of + technologies that enable creation of deterministic networks on IP- + based networks of potentially wide area (on the scale of a corporate + network) potentially bringing the OT network into contact with + Information Technology (IT) traffic and security threats that lie + outside of a tightly controlled and bounded area (such as the + internals of an aircraft). These DetNet technologies have not previously been deployed together on a wide area IP-based network, and thus can present security considerations that may be new to IP-based wide area network designers; this document provides insight into such system-level security considerations. In addition, designers of DetNet components (such as routers) face new security-related challenges in providing DetNet services, for example maintaining reliable isolation between traffic flows in an environment where IT traffic co-mingles with critical reserved-bandwidth OT traffic; this document also examines @@ -248,64 +224,73 @@ management aspects leave off. The exact 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]). A general introduction to the DetNet architecture can be found in [RFC8655] and it is also - recommended to be familiar with the Data Plane model + recommended to be familiar with the DetNet Data Plane [I-D.ietf-detnet-data-plane-framework] and Flow Information Model [I-D.ietf-detnet-flow-information-model]. The DetNet technologies include ways to: o Assign data plane resources for DetNet flows in some or all of the intermediate nodes (routers) along the path of the flow o Provide explicit routes for DetNet flows that do not dynamically change with the network topology in ways that affect the quality of service received by the affected flow(s) 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 document includes sections considering DetNet component design - as well as system design. The latter include threat modeling and + as well as system design. The latter includes threat modeling and analysis, threat impact and mitigation, and the association of attacks with use cases (based on the Use Case Common Themes section - of the DetNet Use Cases). + of the DetNet Use Cases [RFC8578]). The structure of the threat model and threat analysis sections were originally derived from [RFC7384], which also considers time-related security considerations in IP networks. -2. Abbreviations +2. Abbreviations and Terminology - 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, - often in the context of a business or other enterprise - Wikipedia). + often in the context of a business or other enterprise - [IT_DEF]). OT Operational Technology (the hardware and software dedicated to detecting or causing changes in physical processes through direct monitoring and/or control of physical devices such as - valves, pumps, etc. - Wikipedia) + valves, pumps, etc. - [OT_DEF]) MITM Man in the Middle + Component A component of a DetNet system - used here to refer + to any hardware or software element of a DetNet network which + implements DetNet-specific functionality, for example all or part of + a router, switch, or end system. + + Resource Segmentation Used as a more general form for Network + Segmentation (the act or practice of splitting a computer network + into subnetworks, each being a network segment - [RS_DEF]) + 3. Security Considerations for DetNet Component Design As noted above, DetNet provides resource allocation, explicit routes - and redundant path support. Each of these have associated security + and redundant path support. Each of these has associated security implications, which are discussed in this section, in the context of component design. Detection, reporting and appropriate action in the case of packet arrival time violations are also discussed. 3.1. Resource Allocation A DetNet system security designer relies on the premise that any resources allocated to a resource-reserved (OT-type) flow are inviolable, in other words there is no physical possibility within a DetNet component that resources allocated to a given flow can be @@ -323,24 +308,25 @@ The DetNet-specific purpose for constraining the network's ability to re-route OT traffic is to maintain the specified service parameters (such as upper and lower latency boundaries) for a given flow. For example if the network were to re-route a flow (or some part of a flow) based exclusively on statistical path usage metrics, or due to malicious activity, it is possible that the new path would have a latency that is outside the required latency bounds which were designed into the original TE-designed path, thereby violating the quality of service for the affected flow (or part of that flow). - (However, is acceptable for the network to re-route OT traffic in + + However, it is acceptable for the network to re-route OT traffic in such a way as to maintain the specified latency bounds (and any other specified service properties) for any reason, for example in response - to a runtime component or path failure). From a security standpoint, + to a runtime component or path failure. From a security standpoint, the system designer relies on the premise that the packets will be delivered with the specified latency boundaries; thus any component that is involved in controlling or implementing any change of the initially TE-configured flow routes needs to prevent malicious or accidental re-routing of OT flows that might adversely affect delivering the traffic within the specified service parameters. 3.3. Redundant Path Support The DetNet provision for redundant paths (PREOF) (as defined in the @@ -355,69 +341,94 @@ redundant paths sufficient to provide the desired level of reliability (in as much as that reliability can be provided through the use of redundant paths). It is the responsibility of the component designer to ensure that the relevant PREOF operations are executed reliably and securely. (However, note that not all PREOF operations are necessarily implemented in every network; for example a packet re-ordering function may not be necessary if the packets are either not required to be in order, or if the ordering is performed in some other part of the network.) - As noted in Section 7.2, Packet Sequence Number Integrity - Considerations, there is a trust relationship between the pair of - devices that replicate and remove packets, so it is the - responsibility of the system designer to define these relationships - with the appropriate security considerations, and the components must - each uphold the security rights implied by these relationships. + As noted in Section 7.2, Integrity Protection, there is a trust + relationship between the pair of devices that replicate and remove + packets, so it is the responsibility of the system designer to define + these relationships with the appropriate security considerations, and + the components must each uphold the security rights implied by these + relationships. Ideally a redundant path could be specified from end to end of the flow's path, however given that this is not always possible (as described in [RFC8655]) the system designer will need to consider the resulting end-to-end reliability and security resulting from any given arrangment of network segments along the path, each of which provides its individual PREOF implementation and thus its individual level of reliabiilty and security. At the data plane the implementation of PREOF depends on the correct assignment and interpretation of packet sequence numbers, as well as the actions taken based on them, such as elimination. Thus the integrity of these values must be maintained by the component as they - are assigned by the DetNet data plane's Service sub-layer, and + are assigned by the DetNet Data Plane's Service sub-layer, and transported by the Forwarding sub-layer. -3.4. Timing Violation Reporting +3.4. Timing (or other) Violation Reporting Another fundamental assumption of a secure DetNet is that in any case - in which an incoming packet arrives outside of its prescribed time - window or exceeding the reserved flow bandwidth, something can be - done about it. That means that the component's data plane must be - able to detect such cases, then at least alert the control plane, - and/or drop the packet, and/or shut down the link if violations - persist. Logging of such issues may not be adequate, since a delay - in response to the situation could result in material damage, for - example to mechanical devices controlled by the network. + in which an incoming packet arrives with any timing or bandwidth + violation, something can be done about it which doesn't cause damage + to the system. For example having the network shut down a link if a + packet arrives outside of its prescribed time window may serve the + attacker better than it serves the network. That means that the + component's data plane must be able to detect and act on a variety of + such violations, at least alerting the controller plane. Any action + apart from that needs to be carefully considered in the context of + the specific system. Some possible violations that warrant detection + include cases where a packet arrives: + + o Outside of its prescribed time window + + o Within its time window but with a compromised time stamp that + makes it appear that it is not within its window + + o Exceeding the reserved flow bandwidth + + Logging of such issues is unlikely to be adequate, since a delay in + response to the situation could result in material damage, for + example to mechanical devices controlled by the network. Given that + the data plane component probably has no knowledge of the use case of + the network, or its applications and end systems, it would seem + useful for a data plane component to allow the system designer to + configure its actions in the face of such violations. + + Possible direct actions that may be taken at the data plane include + dropping the packet and/or shutting down the link; however if any + such actions are configured to be taken, the system designer must + ensure that such actions do not compromise the continued safe + operation of the system. For example, the controller plane should + mitigate in a timely fashion any potential adverse effect on + mechanical devices controlled by the network. 4. DetNet Security Considerations Compared With DiffServ Security Considerations DetNet is designed to be compatible with DiffServ [RFC2474] as applied to IT traffic in the DetNet. DetNet also incorporates the use of the 6-bit value of the DSCP field of the TOS field of the IP header for flow identification for OT traffic, however the DetNet interpretation of the DSCP value for OT traffic is not equivalent to the PHB selection behavior as defined by DiffServ. Thus security consideration for DetNet have some aspects in common with DiffServ, in fact overlapping 100% with respect to IP IT traffic. Security considerations for these aspects are part of the existing literature on IP network security, specifically the Security - sections of [RFC2474] and [RFC2475]. However DetNet also introduce + sections of [RFC2474] and [RFC2475]. However DetNet also introduces timing and other considerations which are not present in DiffServ, so the DiffServ security considerations are necessary but not sufficient for DetNet. In the case of DetNet OT traffic, the DSCP value, although interpreted differently than in DiffServ, does contribute to determination of the service provided to the packet. Thus in DetNet there are similar consequences to DiffServ for lack of detection of, or incorrect handling of, packets with mismarked DSCP values, and thus many of the points made in the DiffServ draft Security @@ -467,21 +478,21 @@ 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 which attacks are considered out-of-scope for this document, but also which are considered to be the most common threats - (explored further in Section 5.2 (Threat Analysis). Most of the + (explored further in Section 5.2, Threat Analysis). 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 DetNet flows 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 @@ -490,63 +501,59 @@ 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 security analysis to ensure the integrity of the DetNet networks involved. 5.2. Threat Analysis 5.2.1. Delay -5.2.1.1. 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. The delay may be constant or modulated. 5.2.2. 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. -5.2.3. Resource Segmentation or Slicing - -5.2.3.1. Inter-segment Attack +5.2.3. Resource Segmentation (Inter-segment Attack) An attacker can inject traffic that will consume network resources such that it affects DetNet flows. This can be performed using non- DetNet traffic that indirectly affects DetNet traffic (hardware resource exhaustion), or by using DetNet traffic from one DetNet flow that directly affects traffic from different DetNet flows. 5.2.4. Packet Replication and Elimination 5.2.4.1. Replication: Increased Attack Surface Redundancy is intended to increase the robustness and survivability of DetNet flows, and replication over multiple paths can potentially mitigate an attack that is limited to a single path. However, the fact that packets are replicated over multiple paths increases the attack surface of the network, i.e., there are more points in the network that may be subject to attacks. 5.2.4.2. Replication-related Header Manipulation - An attacker can manipulate the replication-related header fields - (R-TAG). This capability opens the door for various types of - attacks. For example: + An attacker can manipulate the replication-related header fields. + This capability opens the door for various types of attacks. For + example: o Forward both replicas - malicious change of a packet SN (Sequence Number) can cause both replicas of the packet to be forwarded. Note that this attack has a similar outcome to a replay attack. o Eliminate both replicas - SN manipulation can be used to cause both replicas to be eliminated. In this case an attacker that has access to a single path can cause packets from other paths to be dropped, thus compromising some of the advantage of path redundancy. @@ -596,22 +603,22 @@ 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, their schedules, or other temporal properties. 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 document we assume they are encrypted - and/or integrity-protected from external attackers. + involved, for the purposes of this document we assume they are + encrypted and/or integrity-protected from external attackers. 5.2.8. Time Synchronization Mechanisms An attacker can use any of the attacks described in [RFC7384] to attack the synchronization protocol, thus affecting the DetNet service. 5.3. Threat Summary A summary of the attacks that were discussed in this section is @@ -667,22 +674,22 @@ network exploit can also include failure or malfunction of mechanical and/or other OT systems. 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 [RFC8578]. Each of the use cases in the DetNet Use Cases - is represented in the table below, including Pro Audio, Electrical + detail in the DetNet Use Cases [RFC8578]. Each of these use cases 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 (People WB), Affect on a single @@ -892,27 +899,29 @@ In a successful controller plane segmentation attack, control messages are acted on by nodes in the network, unbeknownst to the central controller or the network engineer. This has the potential to: o create new DetNet flows (exhausting resources) o drop existing DetNet flows (denial of service) - o add/remove end-stations to a multicast group (loss of privacy) + o add end-stations to a multicast group (loss of privacy) - o modify the DetNet flow attributes (affecting available bandwidth + o remove end-stations from a multicast group (reduction of service) + + o modify the DetNet flow attributes (affecting available bandwidth) 6.4. Replication and Elimination - The Replication and Elimination is relevant only to Data Plane + The Replication and Elimination is relevant only to data plane messages as controller plane messages are not subject to multipath routing. 6.4.1. Increased Attack Surface Covered briefly in Section 6.3, Segmentation Attacks. 6.4.2. Header Manipulation at Elimination Routers Covered briefly in Section 6.3, Segmentation Attacks. @@ -933,21 +942,21 @@ 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. 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. - 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 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. 6.8. Attacks on Time Sync Mechanisms @@ -1058,24 +1068,24 @@ Section 5.2.7. 7.5. Encryption Description DetNet flows can in principle be forwarded in encrypted form at the DetNet layer, however, regarding encryption of IP headers see Section 9. - Alternatively, if the payload is end-to-end encrypted at the - application layer, the DetNet nodes should not have any need to - inspect the payload itself, and thus the DetNet implementation can - be data-agnostic. + DetNet nodes do not have any need to inspect the payload of any + DetNet packets, making them data-agnostic. This means that end- + to- end encryption at the application layer is an acceptable way + to protect user data. Encryption can also be applied at the subnet layer, for example for Ethernet using MACSec, as noted in Section 9. Related attacks Encryption can be used to mitigate recon attacks (Section 5.2.7). However, for a DetNet network to give differentiated quality of service on a flow-by-flow basis, the network must be able to identify the flows individually. This implies that in a recon @@ -1244,62 +1255,62 @@ 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 [RFC8578]. See also Figure 2 for a mapping of the impact of attacks per use case by industry. -8.1. Use Cases by Common Themes +8.1. Association of Attacks to Use Case 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, Mapping Between Themes and Attacks, then provides a summary of the attacks that are applicable to each theme. 8.1.1. Sub-Network Layer DetNet is expected to run over various transmission mediums, with Ethernet being the first identified. 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 document) 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. + Ethernet medium, for example time-aware scheduling using 802.1Qbv + [IEEE802.1Qbv-2015] can protect against excessive use of bandwidth at + the ingress - for other mediums, other mitigations would have to be + implemented to provide analogous protection. 8.1.2. Central Administration A DetNet network can 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. In this document we distinguish between attacks on the DetNet - Controller plane vs. Data plane. But is an attack affecting control - plane packets synonymous with an attack on the control plane itself? - For purposes of this document let us consider an attack on the - control system itself to be out of scope, and consider all attacks - named in this document which are relevant to controller 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. + Controller plane vs. Data Plane. But is an attack affecting + controller plane packets synonymous with an attack on the controller + plane itself? For the purposes of this document let us consider an + attack on the control system itself to be out of scope, and consider + all attacks named in this document which are relevant to controller + 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. 8.1.3. 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. @@ -1329,84 +1340,68 @@ 8.1.4. Data Flow Information Models Data Flow YANG models specific to DetNet networks are specified by DetNet, and thus are 'new' and thus potentially present a new attack surface. 8.1.5. L2 and L3 Integration 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 IP, MPLS-PW, and Ethernet. + protocols such as IP, MPLS Pseudowire, and Ethernet. - There are no specific entries in our table, however that does not - imply that there could be no relevant attacks related to L2,L3 - integration. + There are no specific entries in the mapping table Figure 4, however + that does not imply that there could be no relevant attacks related + to L2-L3 integration. 8.1.6. End-to-End Delivery Packets sent over DetNet are not to be dropped by the network due to congestion. (Packets may however intentionally be dropped for 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. The same result might be obtained by a controller 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. - Packets may also be dropped due to malfunctioning software or - hardware. - -8.1.7. 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. 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 Controller 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. - -8.1.8. Replacement for Proprietary Fieldbuses +8.1.7. Replacement for Proprietary Fieldbuses and Ethernet-based + Networks 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. 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. + and other industries, as well as proprietary non-interoperable + deterministic Ethernet-based networks. DetNet is intended to provide + an open-standards-based alternative to such buses/networks. In cases + where a DetNet intersects with such fieldbuses/networks 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 Controller 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. -8.1.9. Deterministic vs Best-Effort Traffic +8.1.8. Deterministic vs Best-Effort Traffic Most of the themes described in this document address OT (reserved) DetNet flows - this item is intended to address issues related to IT traffic on a DetNet. DetNet is intended to support coexistence of time-sensitive operational (OT, deterministic) traffic and information (IT, "best effort") traffic on the same ("unified") network. With DetNet, this coexistance will become more common, and @@ -1420,238 +1415,247 @@ with the intent of disrupting handling of IT traffic, and/or the goal of interfering with OT traffic. Presumably if the DetNet flow 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. -8.1.10. Deterministic Flows +8.1.9. Deterministic Flows 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 DetNet flow could cause that flow to occupy more bandwidth than it was allocated, resulting in interference with other DetNet 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. -8.1.11. Unused Reserved Bandwidth +8.1.10. Unused Reserved Bandwidth If bandwidth reservations are made for a DetNet flow but the associated bandwidth is not used at any point in time, that bandwidth is made available on the network for best-effort traffic. However, note that security considerations for best-effort traffic on a DetNet network is out of scope of the present document, provided that such an attack does not affect performance for DetNet OT traffic. -8.1.12. Interoperability +8.1.11. 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. Given that the DetNet specifications are unambiguously written and that the implementations are accurate, then this should not in and of itself cause a security concern; however, in the real world, it could be. The network operator can mitigate this through sufficient interoperability testing. -8.1.13. Cost Reductions +8.1.12. 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. Such "low cost" - hardware or software components might present security concerns. + reduction and cost competition among vendors. + + This envisioned breadth of DetNet-enabled products is in general a + positive factor, however implementation flaws in any individual + component can present an attack surface. In addition, implementation + differences between components from different vendors can result in + attack surfaces (resulting from their interaction) which may not + exist in any individual component. Network operators can mitigate such concerns through sufficient - product testing. + product and interoperability testing. -8.1.14. Insufficiently Secure Devices +8.1.13. 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. Software that was originally designed for - operation in isolated OT networks (and thus may not have been - designed to be sufficiently secure, or secure at all) but is then - deployed on a DetNet network that is intended to be highly secure may - present an attack surface. (For example IoT exploits like the Mirai - video-camera botnet ([MIRAI]). + device manufactured. However this raises the possibility that a + vendor might repurpose for DetNet applications a hardware or software + component that was originally designed for operation in an isolated + OT network, and thus may not have been designed to be sufficiently + secure, or secure at all. Deployment of such a device on a DetNet + network that is intended to be highly secure may present an attack + surface. The DetNet network operator may need to take specific actions to - protect such devices. + protect such devices, such as implementing a dedicated security layer + around the device. -8.1.15. DetNet Network Size +8.1.14. 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. 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, presenting a larger attack surface. Similarly Path Manipulation, Path Choice and Time Sync attacks seem more likely relevant to large networks. -8.1.16. Multiple Hops +8.1.15. Multiple Hops 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. + of how the individual driver or firmware operates) could take + proportionately greater advantage of this topology. 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 + in the implementations which have not been tested through extensive use, particularly in the case of early adopters. - Of the attacks we have defined, the ones identified above as relevant - to "large" networks are the most relevant. + Of the attacks we have defined, the ones identified in Section 8.1.14 + as germane to large networks are the most relevant. -8.1.17. Level of Service +8.1.16. 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 DetNet flow, requesting worst case maximum and/or minimum latency for a given path or DetNet flow, 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). Controller 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 controller plane as noted above. + specific flows for attack via the controller plane as noted in + Section 6.7. -8.1.18. Bounded Latency +8.1.17. Bounded Latency 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). -8.1.19. Low Latency +8.1.18. 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. Attacks on the controller plane (as described in the Level of Service - theme) and Delay and Time attacks (as described in the Bounded - Latency theme) both apply here. + theme Section 8.1.16) and Delay and Time attacks (as described in the + Bounded Latency theme Section 8.1.17) both apply here. -8.1.20. Bounded Jitter (Latency Variation) +8.1.19. Bounded Jitter (Latency Variation) DetNet is expected to provide bounded jitter (packet to packet latency variation). Delay attacks can cause packets to vary in their arrival times, resulting in packet to packet latency variation, thereby violating the jitter specification. -8.1.21. Symmetrical Path Delays +8.1.20. Symmetrical Path Delays Some applications would like to specify that the transit delay time values be equal for both the transmit and return paths. Delay attacks can cause path delays to materially differ between paths. Time Sync attacks can corrupt the system's time reference, resulting in path delays that may be perceived to be different (with respect to the "correct" time reference) even if they are not materially different. -8.1.22. Reliability and Availability +8.1.21. 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. 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. + reliability and availability, thus in the mapping table Figure 4 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. -8.1.23. Redundant Paths +8.1.22. 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. Replication-related attacks are by definition applicable here. Controller plane attacks can also interfere with the configuration of redundant paths. -8.1.24. Security Measures +8.1.23. 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. + This is TBD, thus there are no specific entries in the mapping table + Figure 4, however that does not imply that there could be no relevant + attacks. -8.2. Attack Types by Use Case Common Theme +8.2. Summary of Attack Types per Use Case Common Theme - The following table lists the attacks of Section 5, Security Threats, - assigning a number to each type of attack. That number is then used - as a short form identifier for the attack in Figure 5, Mapping - Between Themes and Attacks. + The List of Attacks table Figure 4 lists the attacks of Section 5, + Security Threats, assigning a number to each type of attack. That + number is then used as a short form identifier for the attack in + Figure 5, Mapping Between Themes and Attacks. +--+----------------------------------------+----------------------+ | | Attack | Section | +--+----------------------------------------+----------------------+ | 1|Delay Attack | Section 3.2.1 | +--+----------------------------------------+----------------------+ | 2|DetNet Flow Modification or Spoofing | Section 3.2.2 | +--+----------------------------------------+----------------------+ | 3|Inter-Segment Attack | Section 3.2.3 | +--+----------------------------------------+----------------------+ @@ -1667,23 +1671,24 @@ +--+----------------------------------------+----------------------+ | 9|Control or Signaling Packet Injection | Section 3.2.6.2 | +--+----------------------------------------+----------------------+ |10|Reconnaissance | Section 3.2.7 | +--+----------------------------------------+----------------------+ |11|Attacks on Time Sync Mechanisms | Section 3.2.8 | +--+----------------------------------------+----------------------+ Figure 4: List of Attacks - The following table maps the use case themes presented in this memo - to the attacks of Figure 4. Each row specifies a theme, and the - attacks relevant to this theme are marked with a '+'. + The Mapping Between Themes and Attacks table Figure 5 maps the use + case themes of [RFC8578] (as also enumerated in this document) to the + attacks of Figure 4. Each row specifies a theme, and the attacks + relevant to this theme are marked with a '+'. +----------------------------+--------------------------------+ | Theme | Attack | | +--+--+--+--+--+--+--+--+--+--+--+ | | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Network Layer - AVB/TSN Eth.| +| +| +| +| +| +| +| +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Central Administration | | | | | | +| +| +| +| +| +| +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ @@ -1735,21 +1740,21 @@ +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ |Security Measures | | | | | | | | | | | | +----------------------------+--+--+--+--+--+--+--+--+--+--+--+ Figure 5: Mapping Between Themes and Attacks 8.3. Security Considerations for OAM Traffic This section considers DetNet-specific security considerations for packet traffic that is generated and transmitted over a DetNet as - part of OAM (Operations, Administration and Maintenance). For + part of OAM (Operations, Administration, and Maintenance). For the purposes of this discussion, OAM traffic falls into one of two basic types: o OAM traffic generated by the network itself. The additional bandwidth required for such packets is added by the network administration, presumably transparent to the customer. Security considerations for such traffic are not DetNet-specific (apart from such traffic being subject to the same DetNet-specific security considerations as any other DetNet data flow) and are thus not covered in this document. @@ -1779,41 +1784,42 @@ ([I-D.ietf-detnet-ip]) and delivers service over sub-layer technologies such as MPLS ([I-D.ietf-detnet-mpls]) and IEEE 802.1 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. However, if the DetNet nodes cannot decrypt IPsec traffic, IPSec may - not be a valid option; this is because the DetNet IP data plane + not be a valid option; this is because the DetNet IP Data Plane identifies flows via a 6-tuple that consists of two IP addresses, the transport protocol ID, two transport protocol port numbers and the 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 and MPLS in more detail. 9.1. IP The IP protocol has a long history of security considerations and architectural protection mechanisms. From a data plane perspective - 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 - that were not there before, apart from those already described in the - data-plane-independent threats section Section 5, Security Threats. + DetNet does not add or modify any IP header information, so the + carriage of DetNet traffic over an IP data plane does not introduce + any new security issues that were not there before, apart from those + already described in the data-plane-independent threats section + Section 5, Security Threats. Thus the security considerations for a DetNet based on an IP data plane are purely inherited from the rich IP Security literature and code/application base, and the data-plane-independent section of this 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 @@ -1940,58 +1946,66 @@ Bryant, "DetNet Data Plane Framework", draft-ietf-detnet- data-plane-framework-06 (work in progress), May 2020. [I-D.ietf-detnet-flow-information-model] Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D. Fedyk, "DetNet Flow Information Model", draft-ietf-detnet- flow-information-model-10 (work in progress), May 2020. [I-D.ietf-detnet-ip] Varga, B., Farkas, J., Berger, L., Fedyk, D., and S. - Bryant, "DetNet Data Plane: IP", draft-ietf-detnet-ip-06 - (work in progress), April 2020. + Bryant, "DetNet Data Plane: IP", draft-ietf-detnet-ip-07 + (work in progress), July 2020. [I-D.ietf-detnet-ip-over-tsn] Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet Data Plane: IP over IEEE 802.1 Time Sensitive Networking - (TSN)", draft-ietf-detnet-ip-over-tsn-02 (work in - progress), March 2020. + (TSN)", draft-ietf-detnet-ip-over-tsn-03 (work in + progress), June 2020. [I-D.ietf-detnet-mpls] Varga, B., Farkas, J., Berger, L., Malis, A., Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS", draft-ietf- - detnet-mpls-06 (work in progress), April 2020. + detnet-mpls-10 (work in progress), July 2020. [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. [IEEE802.1AE-2018] IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC Security (MACsec)", 2018, . + [IEEE802.1Qbv-2015] + IEEE Standards Association, "IEEE Standard for Local and + metropolitan area networks -- Bridges and Bridged Networks + - Amendment 25: Enhancements for Scheduled Traffic", 2015, + . + [IEEE802.1Qch-2017] IEEE Standards Association, "IEEE Standard for Local and metropolitan area networks--Bridges and Bridged Networks-- Amendment 29: Cyclic Queuing and Forwarding", 2017, . - [MIRAI] krebsonsecurity.com, "https://krebsonsecurity.com/2016/10/ - hacked-cameras-dvrs-powered-todays-massive-internet- - outage/", 2016. + [IT_DEF] Wikipedia, "IT Definition", 2020, + . + + [OT_DEF] Wikipedia, "OT Definition", 2020, + . [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, DOI 10.17487/RFC2474, December 1998, . [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., and W. Weiss, "An Architecture for Differentiated Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, @@ -2057,26 +2071,28 @@ [RFC8578] Grossman, E., Ed., "Deterministic Networking Use Cases", RFC 8578, DOI 10.17487/RFC8578, May 2019, . [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, October 2019, . + [RS_DEF] Wikipedia, "RS Definition", 2020, + . + Authors' Addresses Tal Mizrahi Huawei Network.IO Innovation Lab Email: tal.mizrahi.phd@gmail.com - Ethan Grossman (editor) Dolby Laboratories, Inc. 1275 Market Street San Francisco, CA 94103 USA Phone: +1 415 645 4726 Email: ethan.grossman@dolby.com URI: http://www.dolby.com