Internet-Draft | I2NSF Capability YANG Data Model | September 2021 |
Hares, et al. | Expires 1 April 2022 | [Page] |
- Workgroup:
- I2NSF Working Group
- Internet-Draft:
- draft-ietf-i2nsf-capability-data-model-19
- Published:
- Intended Status:
- Standards Track
- Expires:
I2NSF Capability YANG Data Model
Abstract
This document defines an information model and the corresponding YANG data model for the capabilities of various Network Security Functions (NSFs) in the Interface to Network Security Functions (I2NSF) framework to centrally manage the capabilities of the various NSFs.¶
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 1 April 2022.¶
Copyright Notice
Copyright (c) 2021 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.¶
1. Introduction
As the industry becomes more sophisticated and network devices (e.g., Internet-of-Things (IoT) devices, autonomous vehicles, and smartphones using Voice over IP (VoIP) and Voice over LTE (VoLTE)) require advanced security protection in various scenarios, security service providers have a lot of problems described in [RFC8192] to provide such network devices with efficient and reliable security services in network infrastructure. To resolve these problems, this document specifies the information and data models of the capabilities of Network Security Functions (NSFs) in a framework of the Interface to Network Security Functions (I2NSF) [RFC8329].¶
NSFs produced by multiple security vendors provide various security capabilities to customers. Multiple NSFs can be combined together to provide security services over the given network traffic, regardless of whether the NSFs are implemented as physical or virtual functions. Security Capabilities describe the functions that Network Security Functions (NSFs) can provide for security policy enforcement. Security Capabilities are independent of the actual security policy that will implement the functionality of the NSF.¶
Every NSF SHOULD be described with the set of capabilities it offers. Security Capabilities enable security functionality to be described in a vendor-neutral manner. Security Capabilities are a market enabler, providing a way to define customized security protection by unambiguously describing the security features offered by a given NSF. Note that this YANG data model constructs the structure of the NSF Monitoring Interface YANG data model [I-D.ietf-i2nsf-nsf-monitoring-data-model] and the NSF-Facing Interface YANG Data Model [I-D.ietf-i2nsf-nsf-facing-interface-dm].¶
This document provides an information model and the corresponding YANG data model [RFC6020][RFC7950] that defines the capabilities of NSFs to centrally manage the capabilities of those NSFs. The NSFs can register their own capabilities into a Network Operator Management (Mgmt) System (i.e., Security Controller) with this YANG data model through the registration interface [RFC8329]. With the database of the capabilities of those NSFs that are maintained centrally, those NSFs can be more easily managed [RFC8329].¶
This YANG data model uses an "Event-Condition-Action" (ECA) policy model that is used as the basis for the design of I2NSF Policy as described in [RFC8329] and Section 3.1. The "ietf-i2nsf-capability" YANG module defined in this document provides the following features:¶
- Definition for event capabilities of network security functions.¶
- Definition for condition capabilities of network security functions.¶
- Definition for action capabilities of network security functions.¶
- Definition for resolution strategy capabilities of network security functions.¶
- Definition for default action capabilities of network security functions.¶
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
This document uses the terminology described in [RFC8329].¶
This document follows the guidelines of [RFC8407], uses the common YANG types defined in [RFC6991], and adopts the Network Management Datastore Architecture (NMDA). The meaning of the symbols in tree diagrams is defined in [RFC8340].¶
3. Information Model of I2NSF NSF Capability
This section provides the I2NSF Capability Information Model (CapIM). A CapIM is a formalization of the functionality that an NSF advertises. This enables the precise specification of what an NSF can do in terms of security policy enforcement, so that computer-based tasks can unambiguously refer to, use, configure, and manage NSFs. Capabilities MUST be defined in a vendor- and technology-independent manner (i.e., regardless of the differences among vendors and individual products).¶
Humans can refer to categories of security controls and understand each other. For instance, network security experts agree on what is meant by the terms "NAT", "filtering", and "VPN concentrator". As a further example, network security experts unequivocally refer to "packet filters" as stateless devices that allow or deny packet forwarding based on various conditions (e.g., source and destination IP addresses, source and destination ports, and IP protocol type fields) [Alshaer].¶
However, more information is required in case of other devices, like stateful firewalls or application layer filters. These devices filter packets or communications, but there are differences in the packets and communications that they can categorize and the states they maintain. Humans deal with these differences by asking more questions to determine the specific category and functionality of the device. Machines can follow a similar approach, which is commonly referred to as question-answering [Hirschman]. In this context, the CapIM and the derived data model can provide important and rich information sources.¶
Analogous considerations can be applied for channel protection protocols, where we all understand that they will protect packets by means of symmetric algorithms whose keys could have been negotiated with asymmetric cryptography, but they may work at different layers and support different algorithms and protocols. To ensure protection, these protocols apply integrity, optionally confidentiality, anti-reply protections, and authentication.¶
The CapIM is intended to clarify these ambiguities by providing a formal description of NSF functionality. The set of functions that are advertised MAY be restricted according to the privileges of the user or application that is viewing those functions. I2NSF Capabilities enable unambiguous specification of the security capabilities available in a (virtualized) networking environment, and their automatic processing by means of computer-based techniques.¶
This CapIM includes enabling a security controller in an I2NSF framework [RFC8329] to properly identify and manage NSFs, and allow NSFs to properly declare their functionality through a Developer's Management System (DMS) [RFC8329], so that they can be used in the correct way.¶
3.1. Design Principles and ECA Policy Model
This document defines an information model for representing NSF capabilities. Some basic design principles for security capabilities and the systems that manage them are:¶
- Independence: Each security capability SHOULD be an independent function, with minimum overlap or dependency on other capabilities. This enables each security capability to be utilized and assembled together freely. More importantly, changes to one capability SHOULD NOT affect other capabilities. This follows the Single Responsibility Principle [Martin] [OODSRP].¶
- Abstraction: Each capability MUST be defined in a vendor- independent manner.¶
- Advertisement: Registration Interface [I-D.ietf-i2nsf-registration-interface-dm] MUST be used to advertise and register the capabilities of each NSF. This same interface MUST be used by other I2NSF Components to determine what Capabilities are currently available to them.¶
- Execution: NSF-Facing Interface [I-D.ietf-i2nsf-nsf-facing-interface-dm] and NSF Monitoring Interface [I-D.ietf-i2nsf-nsf-monitoring-data-model] MUST be used to configure the use of a capability into an NSF and monitor the NSF, respectively. These provide a standardized ability to describe its functionality, and report its processing results, respectively. These facilitate multi-vendor interoperability.¶
- Automation: The system MUST have the ability to auto-discover, auto-negotiate, and auto-update its security capabilities (i.e., without human intervention). These features are especially useful for the management of a large number of NSFs. They are essential for adding smart services (e.g., refinement, analysis, capability reasoning, and optimization) to the security scheme employed. These features are supported by many design patterns, including the Observer Pattern [OODOP], the Mediator Pattern [OODMP], and a set of Message Exchange Patterns [Hohpe]. Registration Interface [I-D.ietf-i2nsf-registration-interface-dm] can register the capabilities of NSFs with the security controller from the request of Developer's Management System providing NSFs and the corresponding security capabilities. Also, this interface can send a query to Developer's Management System in order to find an NSF to satisfy the requested security capability from the security controller that receives a security policy.¶
- Scalability: The management system SHOULD have the capability to scale up/down or scale in/out. Thus, it can meet various performance requirements derived from changeable network traffic or service requests. In addition, security capabilities that are affected by scalability changes SHOULD support reporting statistics to the security controller to assist its decision on whether it needs to invoke scaling or not. NSF Monitoring Interface [I-D.ietf-i2nsf-nsf-monitoring-data-model] can observe the performance of NSFs to let the security controller decide scalability changes of the NSFs.¶
Based on the above principles, this document defines a capability model that enables an NSF to register (and hence advertise) its set of capabilities that other I2NSF Components can use. These capabilities MUST have their access control restricted by a policy; this is out of scope for this document. The set of capabilities provided by a given set of NSFs unambiguously defines the security services offered by the set of NSFs used. The security controller can compare the requirements of users and applications with the set of capabilities that are currently available in order to choose which capabilities of which NSFs are needed to meet those requirements. Note that this choice is independent of vendor, and instead relies specifically on the capabilities (i.e., the description) of the functions provided.¶
Furthermore, NSFs are subject to the updates of security capabilities and software to cope with newly found security attacks or threats, hence new capabilities may be created, and/or existing capabilities may be updated (e.g., by updating its signature and algorithm). New capabilities may be sent to and stored in a centralized repository, or stored separately in a vendor's local repository. In either case, Registration Interface can facilitate this update process to Developer's Management System to let the security controller update its repository for NSFs and their security capabilities.¶
The "Event-Condition-Action" (ECA) policy model in [RFC8329] is used as the basis for the design of the capability model; The following three terms define the structure and behavior of an I2NSF imperative policy rule:¶
- Event: An Event is defined as any important occurrence in time of a change in the system being managed, and/or in the environment of the system being managed. When used in the context of I2NSF Policy Rules, it is used to determine whether the condition clause of an I2NSF Policy Rule can be evaluated or not. Examples of an I2NSF Event include time and user actions (e.g., logon, logoff, and actions that violate an ACL).¶
- Condition: A condition is defined as a set of attributes, features, and/or values that are to be compared with a set of known attributes, features, and/or values in order to determine whether or not the set of actions in that (imperative) I2NSF Policy Rule can be executed or not. Examples of I2NSF conditions include matching attributes of a packet or flow, and comparing the internal state of an NSF with a desired state.¶
- Action: An action is used to control and monitor aspects of NSFs to handle packets or flows when the event and condition clauses are satisfied. NSFs provide security functions by executing various Actions. Examples of I2NSF actions include providing intrusion detection and/or protection, web and flow filtering, and deep packet inspection for packets and flows.¶
An I2NSF Policy Rule is made up of three clauses: an Event clause, a Condition clause, and an Action clause. This structure is also called an ECA (Event-Condition-Action) Policy Rule. A Boolean clause is a logical statement that evaluates to either TRUE or FALSE. It may be made up of one or more terms; if more than one term is present, then each term in the Boolean clause is combined using logical connectives (i.e., AND, OR, and NOT).¶
An I2NSF ECA Policy Rule has the following semantics:¶
Technically, the "Policy Rule" is really a container that aggregates the above three clauses, as well as metadata, which describe the characteristics and behaviors of a capability (or an NSF). Aggregating metadata enables a business logic to be used to prescribe a behavior. For example, suppose a particular ECA Policy Rule contains three actions (A1, A2, and A3, in that order). Action A2 has a priority of 10; actions A1 and A3 have no priority specified. Then, metadata may be used to restrict the set of actions that can be executed when the event and condition clauses of this ECA Policy Rule are evaluated to be TRUE; two examples are: (1) only the first action (A1) is executed, and then the policy rule returns to its caller, or (2) all actions are executed, starting with the highest priority.¶
The above ECA policy model is very general and easily extensible.¶
3.2. Conflict, Resolution Strategy and Default Action
Formally, two I2NSF Policy Rules conflict with each other if:¶
- the Event Clauses of each evaluate to TRUE;¶
- the Condition Clauses of each evaluate to TRUE;¶
- the Action Clauses affect the same object in different ways.¶
For example, if we have two Policy Rules called R1 and R2 in the same Policy:¶
- R1: During 8am-6pm, if traffic is external, then run through firewall¶
- R2: During 7am-8pm, run anti-virus¶
There is no conflict between the two policy rules R1 and R2, since the actions are different. However, consider these two rules called R3 and R4:¶
- R3: During 9am-6pm, allow John to access social networking service websites¶
- R4: During 9am-6pm, disallow all users to access social networking service websites¶
The two policy rules R3 and R4 are now in conflict, between the hours of 9am and 6pm, because the actions of R3 and R4 are different and apply to the same user (i.e., John).¶
Conflicts theoretically compromise the correct functioning of devices. However, NSFs have been designed to cope with these issues. Since conflicts are originated by simultaneously matching rules, an additional process decides the action to be applied, e.g., among the actions which the matching rule would have enforced. This process is described by means of a resolution strategy for conflicts. The finding and handling of conflicted matching rules is performed by resolution strategies in the security controller. The implementation of such resolution strategies is out of scope for I2NSF.¶
On the other hand, it may happen that, if an event is caught, none of the policy rules matches the condition. Note that a packet or flow is handled only when it matches both the event and condition of a policy rule according to the ECA policy model. As a simple case, no condition in the rules may match a packet arriving at the border firewall. In this case, the packet is usually dropped, that is, the firewall has a default behavior of packet dropping in order to manage the cases that are not covered by specific rules.¶
Therefore, this document introduces two further capabilities for an NSF to handle security policy conflicts with resolution strategies and enforce a default action if no rules match.¶
- Resolution Strategies: They can be used to specify how to resolve conflicts that occur between the actions of the same or different policy rules that are matched and contained in this particular NSF;¶
- Default Action: It provides the default behavior to be executed when there are no other alternatives. This action can be either an explicit action or a set of actions.¶
4. Overview of YANG Data Model
This section provides an overview of how the YANG data model can be used in the I2NSF framework described in [RFC8329]. Figure 1 shows the capabilities (e.g., firewall and web filter) of NSFs in the I2NSF Framework. As shown in this figure, a Developer's Management System (DMS) can register NSFs and their capabilities with a Security Controller. To register NSFs in this way, the DMS utilizes the standardized capability YANG data model in this document through the I2NSF Registration Interface [RFC8329]. That is, this Registration Interface uses the YANG module described in this document to describe the capabilities of an NSF that is registered with the Security Controller. As described in [RFC8192], with the usage of Registration Interface and the YANG module in this document, the NSFs manufactured by multiple vendors can be managed together by the Security Controller in a centralized way and be updated dynamically by each vendor as the NSF has software or hardware updates.¶
In Figure 1, a new NSF at a Developer's Management System has capabilities of Firewall (FW) and Web Filter (WF), which are denoted as (Cap = {FW, WF}), to support Event-Condition-Action (ECA) policy rules where 'E', 'C', and 'A' mean "Event", "Condition", and "Action", respectively. The condition involves IPv4 or IPv6 datagrams, and the action includes "Allow" and "Deny" for those datagrams.¶
Note that the NSF-Facing Interface [RFC8329] is used by the Security Controller to configure the security policy rules of NSFs (e.g., firewall and Distributed-Denial-of-Service (DDoS) attack mitigator) with the capabilities of the NSFs registered with the Security Controller.¶
A use case of an NSF with the capabilities of firewall and web filter is described as follows.¶
- If a network administrator wants to apply security policy rules to block malicious users with firewall and web filter, it is a tremendous burden for a network administrator to apply all of the needed rules to NSFs one by one. This problem can be resolved by managing the capabilities of NSFs as described in this document.¶
- If a network administrator wants to block IPv4 or IPv6 packets from malicious users, the network administrator sends a security policy rule to block the users to the Network Operator Management System (i.e., Security Controller) using the I2NSF Consumer-Facing Interface.¶
- When the Network Operator Management System receives the security policy rule, it automatically sends that security policy rule to appropriate NSFs (i.e., NSF-m in Developer's Management System A and NSF-1 in Developer's Management System B) which can support the capabilities (i.e., IPv6). This lets an I2NSF User not consider which specific NSF(s) will work for the security policy rule.¶
- If NSFs encounter the suspicious IPv4 or IPv6 packets of malicious users, they can filter the packets out according to the configured security policy rule. Therefore, the security policy rule against the malicious users' packets can be automatically applied to appropriate NSFs without human intervention.¶
5. YANG Tree Diagram
This section shows a YANG tree diagram of capabilities of network security functions, as defined in the Section 3.¶
5.1. Network Security Function (NSF) Capabilities
This section explains a YANG tree diagram of NSF capabilities and its features. Figure 2 shows a YANG tree diagram of NSF capabilities. The NSF capabilities in the tree include time capabilities, event capabilities, condition capabilities, action capabilities, resolution strategy capabilities, and default action capabilities. Those capabilities can be tailored or extended according to a vendor's specific requirements. Refer to the NSF capabilities information model for detailed discussion in Section 3.¶
The data model in this document provides identities for the capabilities of NSFs. Every identity in the data model represents the capability of an NSF. Each identity is explained in the description of the identity.¶
Event capabilities are used to specify the capabilities that describe an event that would trigger the evaluation of the condition clause of the I2NSF Policy Rule. The defined event capabilities are system event, system alarm, and time. Time capabilities are used to specify the capabilities which describe when to execute the I2NSF policy rule. The time capabilities are defined in terms of absolute time and periodic time. The absolute time means the exact time to start or end. The periodic time means repeated time like day, week, month, or year.¶
Condition capabilities are used to specify capabilities of a set of attributes, features, and/or values that are to be compared with a set of known attributes, features, and/or values in order to determine whether a set of actions needs to be executed or not so that an imperative I2NSF policy rule can be executed. In this document, two kinds of condition capabilities are used to classify different capabilities of NSFs such as generic-nsf-capabilities and advanced-nsf-capabilities. First, the generic-nsf-capabilities define NSFs that operate on packet header for layer 2 (i.e., Ethernet capability), layer 3 (i.e., IPv4 capability, IPv6 capability, ICMPv4 capability, and ICMPv6 capability.), and layer 4 (i.e., TCP capability, UDP capability, SCTP capability, and DCCP capability). Second, the advanced-nsf-capabilities define NSFs that operate on features different from the generic-nsf-capabilities, e.g., the payload, cross flow state, application layer, traffic statistics, network behavior, etc. This document defines the advanced-nsf into two categories such as content-security-control and attack-mitigation-control.¶
- Content security control is an NSF that evaluates the payload of a packet, such as Intrusion Prevention System (IPS), URL-Filtering, Antivirus, and VoIP/VoLTE Filter.¶
- Attack mitigation control is an NSF that mitigates an attack such as anti-DDoS (DDoS-mitigator).¶
The advanced-nsf can be extended with other types of NSFs. This document only provides five advanced-nsf capabilities, i.e., IPS capability, URL-Filtering capability, Antivirus capability, VoIP/VoLTE Filter capability, and Anti-DDoS capability. Note that VoIP and VoLTE are merged into a single capability in this document because VoIP and VoLTE use the Session Initiation Protocol (SIP) [RFC3261] for a call setup. See Section 3.1 for more information about the condition in the ECA policy model.¶
The context capabilities provide extra information for the condition. The given context conditions are application filter, target, user condition, and geography location. The application filter capability is capability in matching the packet based on the application protocol, such as HTTP, HTTPS, FTP, etc. The target capability is capability in matching the type of the target devices, such as PC, IoT, Network Infrastructure devices, etc. The user condition is capability in matching the users of the network by mapping each user ID to an IP address. Users can be combined into one group. The geography location capability is capability in matching the geographical location of a source or destination of a packet.¶
Action capabilities are used to specify the capabilities that describe the control and monitoring aspects of flow-based NSFs when the event and condition clauses are satisfied. The action capabilities are defined as ingress-action capability, egress-action capability, and log-action capability. See Section 3.1 for more information about the action in the ECA policy model. Also, see Section 7.2 (NSF-Facing Flow Security Policy Structure) in [RFC8329] for more information about the ingress and egress actions. In addition, see Section 9.1 (Flow-Based NSF Capability Characterization) in [RFC8329] and Section 7.5 (NSF Logs) in [I-D.ietf-i2nsf-nsf-monitoring-data-model] for more information about logging at NSFs.¶
Resolution strategy capabilities are used to specify the capabilities that describe conflicts that occur between the actions of the same or different policy rules that are matched and contained in this particular NSF. The resolution strategy capabilities are defined as First Matching Rule (FMR), Last Matching Rule (LMR), Prioritized Matching Rule (PMR), Prioritized Matching Rule with Errors (PMRE), and Prioritized Matching Rule with No Errors (PMRN). See Section 3.2 for more information about the resolution strategy.¶
Default action capabilities are used to specify the capabilities that describe how to execute I2NSF policy rules when no rule matches a packet. The default action capabilities are defined as pass, drop, rate-limit, and mirror. See Section 3.2 for more information about the default action.¶
6. YANG Data Model of I2NSF NSF Capability
This section introduces a YANG module for NSFs' capabilities, as defined in the Section 3.¶
It makes references to¶
- [RFC0768]¶
- [RFC0791]¶
- [RFC0792]¶
- [RFC0854]¶
- [RFC0959]¶
- [RFC1939]¶
- [RFC2474]¶
- [RFC2818]¶
- [RFC3168]¶
- [RFC3261]¶
- [RFC3501]¶
- [RFC4250]¶
- [RFC4340]¶
- [RFC4443]¶
- [RFC4766]¶
- [RFC4960]¶
- [RFC5103]¶
- [RFC5321]¶
- [RFC5595]¶
- [RFC6335]¶
- [RFC6437]¶
- [RFC6691]¶
- [RFC6864]¶
- [RFC7230]¶
- [RFC7231]¶
- [RFC7323]¶
- [RFC8200]¶
- [RFC8329]¶
- [RFC8805]¶
- [IEEE802.3-2018]¶
- [IANA-Protocol-Numbers]¶
- [I-D.ietf-tcpm-rfc793bis]¶
- [I-D.ietf-tcpm-accurate-ecn]¶
- [I-D.ietf-tsvwg-udp-options]¶
- [I-D.ietf-i2nsf-nsf-monitoring-data-model]¶
7. IANA Considerations
This document requests IANA to register the following URI in the "IETF XML Registry" [RFC3688]:¶
ID: yang:ietf-i2nsf-capability URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-capability Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. Filename: [ TBD-at-Registration ] Reference: [ RFC-to-be ]¶
This document requests IANA to register the following YANG module in the "YANG Module Names" registry [RFC7950][RFC8525]:¶
Name: ietf-i2nsf-capability Maintained by IANA? N Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-capability Prefix: nsfcap Module: Reference: [ RFC-to-be ]¶
8. Privacy Considerations
This YANG module specifies the capabilities for NSFs. Some of the capabilities in this document MAY require highly sensitive private data to operate properly. The usage of such capability MUST be reported to the users and permitted before using the private information related to the capability. Using any of the capabilities that require private data MUST preserve the privacy by preventing any leakage or unauthorized disclosure of the private data.¶
In regards to the privacy data used, the security for accessibility of the data should be tightly secured and monitored. The Security Considerations are discussed in Section 9.¶
9. Security Considerations
The YANG module specified in this document defines a data schema designed to be accessed through network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest layer of NETCONF protocol layers MUST use Secure Shell (SSH) [RFC4254][RFC6242] as a secure transport layer. The lowest layer of RESTCONF protocol layers MUST use HTTP over Transport Layer Security (TLS), that is, HTTPS [RFC7230][RFC8446] as a secure transport layer.¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides a means of restricting access to specific NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and contents. Thus, NACM SHOULD be used to restrict the NSF registration from unauthorized users.¶
There are a number of data nodes defined in this YANG module that are writable, creatable, and deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations to these data nodes could have a negative effect on network and security operations. These data nodes are collected into a single list node. This list node is defined by list nsf with the following sensitivity/vulnerability:¶
- list nsf: An attacker could alter the security capabilities associated with an NSF by disabling or enabling the functionality of the security capabilities of the NSF.¶
Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes with their sensitivity/vulnerability:¶
- list nsf: The leak of this node to an attacker could reveal the specific configuration of security controls to an attacker. An attacker can craft an attack path that avoids observation or mitigations; one may reveal topology information to inform additional targets or enable lateral movement; one enables the construction of an attack path that avoids observation or mitigations; one provides an indication that the operator has discovered the attack.¶
Some of the features that this document defines capability indicators for are highly sensitive and/or privileged operations that inherently require access to individuals' private data. These are subtrees and data nodes that are considered privacy sensitive:¶
- voip-volte-filtering-capability: The NSF that is able to filter VoIP/VoLTE calls might identify certain individual identification.¶
- user-condition-capabilities: The capability uses a set of IP addresses mapped to users.¶
- geography-capabilities: The IP address used in this capability can identify a user's geographical location.¶
It is noted that some private information is made accessible in this manner. Thus, the nodes/entities given access to this data MUST be tightly secured, monitored, and audited to prevent leakage or other unauthorized disclosure of private data. Refer to [RFC6973] for the description of privacy aspects that protocol designers (including YANG data model designers) should consider along with regular security and privacy analysis.¶
10. References
10.1. Normative References
- [RFC0768]
- Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI 10.17487/RFC0768, , <https://www.rfc-editor.org/info/rfc768>.
- [RFC0791]
- Postel, J., "Internet Protocol", STD 5, RFC 791, DOI 10.17487/RFC0791, , <https://www.rfc-editor.org/info/rfc791>.
- [RFC0792]
- Postel, J., "Internet Control Message Protocol", STD 5, RFC 792, DOI 10.17487/RFC0792, , <https://www.rfc-editor.org/info/rfc792>.
- [RFC0854]
- Postel, J. and J. Reynolds, "Telnet Protocol Specification", STD 8, RFC 854, DOI 10.17487/RFC0854, , <https://www.rfc-editor.org/info/rfc854>.
- [RFC0959]
- Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9, RFC 959, DOI 10.17487/RFC0959, , <https://www.rfc-editor.org/info/rfc959>.
- [RFC1939]
- Myers, J. and M. Rose, "Post Office Protocol - Version 3", STD 53, RFC 1939, DOI 10.17487/RFC1939, , <https://www.rfc-editor.org/info/rfc1939>.
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [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, , <https://www.rfc-editor.org/info/rfc2474>.
- [RFC3168]
- Ramakrishnan, K., Floyd, S., and D. Black, "The Addition of Explicit Congestion Notification (ECN) to IP", RFC 3168, DOI 10.17487/RFC3168, , <https://www.rfc-editor.org/info/rfc3168>.
- [RFC3261]
- Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, , <https://www.rfc-editor.org/info/rfc3261>.
- [RFC3501]
- Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, DOI 10.17487/RFC3501, , <https://www.rfc-editor.org/info/rfc3501>.
- [RFC3688]
- Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
- [RFC4250]
- Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH) Protocol Assigned Numbers", RFC 4250, DOI 10.17487/RFC4250, , <https://www.rfc-editor.org/info/rfc4250>.
- [RFC4254]
- Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Connection Protocol", RFC 4254, DOI 10.17487/RFC4254, , <https://www.rfc-editor.org/info/rfc4254>.
- [RFC4340]
- Kohler, E., Handley, M., and S. Floyd, "Datagram Congestion Control Protocol (DCCP)", RFC 4340, DOI 10.17487/RFC4340, , <https://www.rfc-editor.org/info/rfc4340>.
- [RFC4443]
- Conta, A., Deering, S., and M. Gupta, Ed., "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification", STD 89, RFC 4443, DOI 10.17487/RFC4443, , <https://www.rfc-editor.org/info/rfc4443>.
- [RFC4766]
- Wood, M. and M. Erlinger, "Intrusion Detection Message Exchange Requirements", RFC 4766, DOI 10.17487/RFC4766, , <https://www.rfc-editor.org/info/rfc4766>.
- [RFC4960]
- Stewart, R., Ed., "Stream Control Transmission Protocol", RFC 4960, DOI 10.17487/RFC4960, , <https://www.rfc-editor.org/info/rfc4960>.
- [RFC5103]
- Trammell, B. and E. Boschi, "Bidirectional Flow Export Using IP Flow Information Export (IPFIX)", RFC 5103, DOI 10.17487/RFC5103, , <https://www.rfc-editor.org/info/rfc5103>.
- [RFC5321]
- Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, DOI 10.17487/RFC5321, , <https://www.rfc-editor.org/info/rfc5321>.
- [RFC5595]
- Fairhurst, G., "The Datagram Congestion Control Protocol (DCCP) Service Codes", RFC 5595, DOI 10.17487/RFC5595, , <https://www.rfc-editor.org/info/rfc5595>.
- [RFC6020]
- Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/info/rfc6020>.
- [RFC6241]
- Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/info/rfc6241>.
- [RFC6242]
- Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
- [RFC6335]
- Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cheshire, "Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry", BCP 165, RFC 6335, DOI 10.17487/RFC6335, , <https://www.rfc-editor.org/info/rfc6335>.
- [RFC6437]
- Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, "IPv6 Flow Label Specification", RFC 6437, DOI 10.17487/RFC6437, , <https://www.rfc-editor.org/info/rfc6437>.
- [RFC6864]
- Touch, J., "Updated Specification of the IPv4 ID Field", RFC 6864, DOI 10.17487/RFC6864, , <https://www.rfc-editor.org/info/rfc6864>.
- [RFC6991]
- Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
- [RFC7230]
- Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing", RFC 7230, DOI 10.17487/RFC7230, , <https://www.rfc-editor.org/info/rfc7230>.
- [RFC7231]
- Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content", RFC 7231, DOI 10.17487/RFC7231, , <https://www.rfc-editor.org/info/rfc7231>.
- [RFC7323]
- Borman, D., Braden, B., Jacobson, V., and R. Scheffenegger, Ed., "TCP Extensions for High Performance", RFC 7323, DOI 10.17487/RFC7323, , <https://www.rfc-editor.org/info/rfc7323>.
- [RFC7950]
- Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
- [RFC8040]
- Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
- [RFC8200]
- Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, , <https://www.rfc-editor.org/info/rfc8200>.
- [RFC8340]
- Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.
- [RFC8341]
- Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/rfc8341>.
- [RFC8407]
- Bierman, A., "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", BCP 216, RFC 8407, DOI 10.17487/RFC8407, , <https://www.rfc-editor.org/info/rfc8407>.
- [RFC8446]
- Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.
- [RFC8525]
- Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K., and R. Wilton, "YANG Library", RFC 8525, DOI 10.17487/RFC8525, , <https://www.rfc-editor.org/info/rfc8525>.
- [I-D.ietf-tcpm-accurate-ecn]
- Briscoe, B., Kühlewind, M., and R. Scheffenegger, "More Accurate ECN Feedback in TCP", Work in Progress, Internet-Draft, draft-ietf-tcpm-accurate-ecn-15, , <https://www.ietf.org/archive/id/draft-ietf-tcpm-accurate-ecn-15.txt>.
- [I-D.ietf-tsvwg-udp-options]
- Touch, J., "Transport Options for UDP", Work in Progress, Internet-Draft, draft-ietf-tsvwg-udp-options-13, , <https://www.ietf.org/archive/id/draft-ietf-tsvwg-udp-options-13.txt>.
- [I-D.ietf-i2nsf-nsf-monitoring-data-model]
- Jeong, J. (., Lingga, P., Hares, S., Xia, L. (., and H. Birkholz, "I2NSF NSF Monitoring Interface YANG Data Model", Work in Progress, Internet-Draft, draft-ietf-i2nsf-nsf-monitoring-data-model-09, , <https://www.ietf.org/archive/id/draft-ietf-i2nsf-nsf-monitoring-data-model-09.txt>.
- [I-D.ietf-i2nsf-nsf-facing-interface-dm]
- Kim, J. (., Jeong, J. (., Park, J., Hares, S., and Q. Lin, "I2NSF Network Security Function-Facing Interface YANG Data Model", Work in Progress, Internet-Draft, draft-ietf-i2nsf-nsf-facing-interface-dm-13, , <https://www.ietf.org/archive/id/draft-ietf-i2nsf-nsf-facing-interface-dm-13.txt>.
- [I-D.ietf-i2nsf-registration-interface-dm]
- Hyun, S., Jeong, J. P., Roh, T., Wi, S., and J. Park, "I2NSF Registration Interface YANG Data Model", Work in Progress, Internet-Draft, draft-ietf-i2nsf-registration-interface-dm-11, , <https://www.ietf.org/archive/id/draft-ietf-i2nsf-registration-interface-dm-11.txt>.
10.2. Informative References
- [RFC2818]
- Rescorla, E., "HTTP Over TLS", RFC 2818, DOI 10.17487/RFC2818, , <https://www.rfc-editor.org/info/rfc2818>.
- [RFC6691]
- Borman, D., "TCP Options and Maximum Segment Size (MSS)", RFC 6691, DOI 10.17487/RFC6691, , <https://www.rfc-editor.org/info/rfc6691>.
- [RFC6973]
- Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., Morris, J., Hansen, M., and R. Smith, "Privacy Considerations for Internet Protocols", RFC 6973, DOI 10.17487/RFC6973, , <https://www.rfc-editor.org/info/rfc6973>.
- [RFC8192]
- Hares, S., Lopez, D., Zarny, M., Jacquenet, C., Kumar, R., and J. Jeong, "Interface to Network Security Functions (I2NSF): Problem Statement and Use Cases", RFC 8192, DOI 10.17487/RFC8192, , <https://www.rfc-editor.org/info/rfc8192>.
- [RFC8329]
- Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R. Kumar, "Framework for Interface to Network Security Functions", RFC 8329, DOI 10.17487/RFC8329, , <https://www.rfc-editor.org/info/rfc8329>.
- [RFC8805]
- Kline, E., Duleba, K., Szamonek, Z., Moser, S., and W. Kumari, "A Format for Self-Published IP Geolocation Feeds", RFC 8805, DOI 10.17487/RFC8805, , <https://www.rfc-editor.org/info/rfc8805>.
- [I-D.ietf-tcpm-rfc793bis]
- Eddy, W. M., "Transmission Control Protocol (TCP) Specification", Work in Progress, Internet-Draft, draft-ietf-tcpm-rfc793bis-25, , <https://www.ietf.org/archive/id/draft-ietf-tcpm-rfc793bis-25.txt>.
- [IANA-Protocol-Numbers]
- "Assigned Internet Protocol Numbers", Available: https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml, .
- [IEEE802.3-2018]
- Committee, I. S., "IEEE 802.3-2018 - IEEE Standard for Ethernet", , <https://ieeexplore.ieee.org/document/8457469>.
- [Alshaer]
- Shaer, Al., Hamed, E., and H. Hamed, "Modeling and management of firewall policies", .
- [Hirschman]
- Hirschman, L. and R. Gaizauskas, "Natural Language Question Answering: The View from Here", Natural Language Engineering 7:4, pgs 275-300, Cambridge University Press , .
- [Hohpe]
- Hohpe, G. and B. Woolf, "Enterprise Integration Patterns", ISBN 0-32-120068-3 , .
- [Martin]
- Martin, R.C., "Agile Software Development, Principles, Patterns, and Practices", Prentice-Hall , ISBN: 0-13-597444-5 , .
- [OODMP]
- "https://www.oodesign.com/mediator-pattern.html".
- [OODOP]
- "https://www.oodesign.com/mediator-pattern.html".
- [OODSRP]
- "https://www.oodesign.com/mediator-pattern.html".
Appendix A. Configuration Examples
This section shows configuration examples of "ietf-i2nsf-capability" module for capabilities registration of general firewall.¶
A.1. Example 1: Registration for the Capabilities of a General Firewall
This section shows a configuration example for the capabilities registration of a general firewall in either an IPv4 network or an IPv6 network.¶
Figure 4 shows the configuration XML for the capabilities registration of a general firewall as an NSF in an IPv4 network. Its capabilities are as follows.¶
- The name of the NSF is general_firewall.¶
- The NSF can inspect the IPv4 protocol header field, flow direction, source address(es), and destination address(es)¶
- The NSF can inspect the port number(s) and flow direction for the transport layer protocol, i.e., TCP and UDP.¶
- The NSF can control whether the packets are allowed to pass, drop, or mirror.¶
In addition, Figure 5 shows the configuration XML for the capabilities registration of a general firewall as an NSF in an IPv6 network. Its capabilities are as follows.¶
- The name of the NSF is general_firewall.¶
- The NSF can inspect IPv6 next header, flow direction, source address(es), and destination address(es)¶
- The NSF can inspect the port number(s) and flow direction for the transport layer protocol, i.e., TCP and UDP.¶
- The NSF can control whether the packets are allowed to pass, drop, or mirror.¶
A.2. Example 2: Registration for the Capabilities of a Time-based Firewall
This section shows a configuration example for the capabilities registration of a time-based firewall in either an IPv4 network or an IPv6 network.¶
Figure 6 shows the configuration XML for the capabilities registration of a time-based firewall as an NSF in an IPv4 network. Its capabilities are as follows.¶
- The name of the NSF is time_based_firewall.¶
- The NSF can execute the security policy rule according to absolute time and periodic time.¶
- The NSF can inspect the IPv4 protocol header field, flow direction, source address(es), and destination address(es).¶
- The NSF can control whether the packets are allowed to pass, drop, or mirror.¶
In addition, Figure 7 shows the configuration XML for the capabilities registration of a time-based firewall as an NSF in an IPv6 network. Its capabilities are as follows.¶
- The name of the NSF is time_based_firewall.¶
- The NSF can execute the security policy rule according to absolute time and periodic time.¶
- The NSF can inspect the IPv6 protocol header field, flow direction, source address(es), and destination address(es).¶
- The NSF can control whether the packets are allowed to pass, drop, or mirror.¶
A.3. Example 3: Registration for the Capabilities of a Web Filter
This section shows a configuration example for the capabilities registration of a web filter.¶
Figure 8 shows the configuration XML for the capabilities registration of a web filter as an NSF. Its capabilities are as follows.¶
A.4. Example 4: Registration for the Capabilities of a VoIP/VoLTE Filter
This section shows a configuration example for the capabilities registration of a VoIP/VoLTE filter.¶
Figure 9 shows the configuration XML for the capabilities registration of a VoIP/VoLTE filter as an NSF. Its capabilities are as follows.¶
A.5. Example 5: Registration for the Capabilities of a HTTP and HTTPS Flood Mitigator
This section shows a configuration example for the capabilities registration of a HTTP and HTTPS flood mitigator.¶
Figure 10 shows the configuration XML for the capabilities registration of a HTTP and HTTPS flood mitigator as an NSF. Its capabilities are as follows.¶
Appendix B. Acknowledgments
This work was supported by Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korea MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based Security Intelligence Technology Development for the Customized Security Service Provisioning). This work was supported in part by the IITP grant funded by the MSIT (2020-0-00395, Standard Development of Blockchain based Network Management Automation Technology).¶
Appendix C. Contributors
This document is made by the group effort of I2NSF working group. Many people actively contributed to this document, such as Acee Lindem, Roman Danyliw, and Tom Petch. The authors sincerely appreciate their contributions.¶
The following are co-authors of this document:¶
Patrick Lingga Department of Electrical and Computer Engineering Sungkyunkwan University 2066 Seo-ro Jangan-gu Suwon, Gyeonggi-do 16419 Republic of Korea EMail: patricklink@skku.edu¶
Liang Xia Huawei 101 Software Avenue Nanjing, Jiangsu 210012 China EMail: Frank.Xialiang@huawei.com¶
Cataldo Basile Politecnico di Torino Corso Duca degli Abruzzi, 34 Torino, 10129 Italy EMail: cataldo.basile@polito.it¶
John Strassner Huawei 2330 Central Expressway Santa Clara, CA 95050 USA EMail: John.sc.Strassner@huawei.com¶
Diego R. Lopez Telefonica I+D Zurbaran, 12 Madrid, 28010 Spain Email: diego.r.lopez@telefonica.com¶
Hyoungshick Kim Department of Computer Science and Engineering Sungkyunkwan University 2066 Seo-ro Jangan-gu Suwon, Gyeonggi-do 16419 Republic of Korea EMail: hyoung@skku.edu¶
Daeyoung Hyun Department of Computer Science and Engineering Sungkyunkwan University 2066 Seo-ro Jangan-gu Suwon, Gyeonggi-do 16419 Republic of Korea EMail: dyhyun@skku.edu¶
Dongjin Hong Department of Electronic, Electrical and Computer Engineering Sungkyunkwan University 2066 Seo-ro Jangan-gu Suwon, Gyeonggi-do 16419 Republic of Korea EMail: dong.jin@skku.edu¶
Jung-Soo Park Electronics and Telecommunications Research Institute 218 Gajeong-Ro, Yuseong-Gu Daejeon, 34129 Republic of Korea EMail: pjs@etri.re.kr¶
Tae-Jin Ahn Korea Telecom 70 Yuseong-Ro, Yuseong-Gu Daejeon, 305-811 Republic of Korea EMail: taejin.ahn@kt.com¶
Se-Hui Lee Korea Telecom 70 Yuseong-Ro, Yuseong-Gu Daejeon, 305-811 Republic of Korea EMail: sehuilee@kt.com¶