This document defines an information model and a YANG data model for Registration Interface between Security Controller and Developer's Management System (DMS) in the Interface to Network Security Functions (I2NSF) framework to register Network Security Functions (NSF) of the DMS with the Security Controller. The objective of these information and data models is to support NSF capability registration and query via I2NSF Registration Interface.¶
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A number of Network Security Functions (NSF) may exist in the Interface to Network Security Functions (I2NSF) framework [RFC8329]. Since each of these NSFs likely has different security capabilities from each other, it is important to register the security capabilities of the NSF with the security controller. In addition, it is required to search NSFs of some required security capabilities on demand. As an example, if additional security capabilities are required to serve some security service request(s) from an I2NSF user, the security controller SHOULD be able to request the DMS for NSFs that have the required security capabilities.¶
This document describes an information model (see Section 4) and a YANG [RFC7950] data model (see Section 5) for the I2NSF Registration Interface [RFC8329] between the security controller and the developer's management system (DMS) to support NSF capability registration and query via the registration interface. It also describes the operations which SHOULD be performed by the security controller and the DMS via the Registration Interface using the defined model.¶
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.¶
Network Security Function (NSF): A function that is responsible for a specific treatment of received packets. A Network Security Function can act at various layers of a protocol stack (e.g., at the network layer or other OSI layers). Sample Network Security Service Functions are as follows: Firewall, Intrusion Prevention/Detection System (IPS/IDS), Deep Packet Inspection (DPI), Application Visibility and Control (AVC), network virus and malware scanning, sandbox, Data Loss Prevention (DLP), Distributed Denial of Service (DDoS) mitigation and TLS proxy.¶
Data Model: A data model is a representation of concepts of interest to an environment in a form that is dependent on data repository, data definition language, query language, implementation language, and protocol.¶
Information Model: An information model is a representation of concepts of interest to an environment in a form that is independent of data repository, data definition language, query language, implementation language, and protocol.¶
YANG: This document follows the guidelines of [RFC8407], uses the common YANG types defined in [RFC6991], and adopts the Network Management Datastore
Architecture (NMDA) [RFC8342]. The meaning of the symbols in tree diagrams is
defined in [RFC8340].¶
Registering NSFs to I2NSF framework: Developer's Management System (DMS) in I2NSF framework is typically run by an NSF vendor, and uses Registration Interface to provide NSFs developed by the NSF vendor to Security Controller. DMS registers NSFs and their capabilities to I2NSF framework through Registration Interface. For the registered NSFs, Security Controller maintains a catalog of the capabilities of those NSFs.¶
Updating the capabilities of registered NSFs: After an NSF is registered into Security Controller, some modifications on the capability of the NSF MAY be required later. In this case, DMS uses Registration Interface to update the capability of the NSF, and this update SHOULD be reflected in the catalog of NSFs.¶
Asking DMS about some required capabilities: In cases that some security capabilities are required to serve the security service request from an I2NSF user, Security Controller searches through the registered NSFs to find ones that can provide the required capabilities. But Security Controller might fail to find any NSFs having the required capabilities among the registered NSFs. In this case, Security Controller needs to request DMS for additional NSF(s) that can provide the required security capabilities via Registration Interface.¶
The I2NSF registration interface is used by Security Controller and Developer's Management System (DMS) in I2NSF framework. The following summarizes the operations done through the registration interface:¶
DMS registers NSFs and their capabilities to Security Controller via the registration interface. DMS also uses the registration interface to update the capabilities of the NSFs registered previously.¶
In case that Security Controller fails to find some required capabilities from any registered NSF that can provide , Security Controller queries DMS about NSF(s) having the required capabilities via the registration interface.¶
Figure 1 shows the information model of the I2NSF registration interface, which consists of two submodels: NSF capability registration and NSF capability query. Each submodel is used for the operations listed above. The remainder of this section will provide in-depth explanations of each submodel.¶
This submodel is used by DMS to register an NSF with Security Controller. Figure 2 shows how this submodel is constructed. The most important part in Figure 2 is the NSF capability, and this specifies the set of capabilities that the NSF to be registered can offer. The NSF Name contains a unique name of this NSF with the specified set of capabilities. When registering the NSF, DMS additionally includes the network access information of the NSF which is required to enable network communications with the NSF.¶
The following will further explain the NSF capability information and the NSF access information in more detail.¶
NSF Capability Information basically describes the security capabilities of an NSF. In Figure 3, we show capability objects of an NSF. Following the information model of NSF capabilities defined in [I-D.ietf-i2nsf-capability-data-model], we share the same I2NSF security capabilities: Time Capabilities, Event Capabilities, Condition Capabilities, Action Capabilities, Resolution Strategy Capabilities, Default Action Capabilities, and IPsec Method [RFC9061]. Also, NSF Capability Information additionally contains the performance capabilities of an NSF as shown in Figure 3.¶
This information represents the processing capability of an NSF. Assuming that the current workload status of each NSF is being collected through NSF monitoring [I-D.ietf-i2nsf-nsf-monitoring-data-model], this capability information of the NSF can be used to determine whether the NSF is in congestion by comparing it with the current workload of the NSF. Moreover, this information can specify an available amount of each type of resource, such as processing power which are available on the NSF. (The registration interface can control the usages and limitations of the created instance and make the appropriate request according to the status.) As illustrated in Figure 4, this information consists of two items: Processing and Bandwidth. Processing information describes the NSF's available processing power. Bandwidth describes the information about available network amount in two cases, outbound, inbound. These two information can be used for the NSF's instance request.¶
NSF Access Information contains the followings that are required to communicate with an NSF: IPv4 address, IPv6 address, port number, and supported transport protocol(s) (e.g., Virtual Extensible LAN (VXLAN) [RFC7348], Generic Protocol Extension for VXLAN (VXLAN-GPE) [I-D.ietf-nvo3-vxlan-gpe], Generic Route Encapsulation (GRE), Ethernet etc.).
In this document, NSF Access Information is used to identify a specific NSF instance (i.e. NSF Access Information is the signature(unique identifier) of an NSF instance in the overall system).¶
Security Controller MAY require some additional capabilities to serve the security service request from an I2NSF user, but none of the registered NSFs has the required capabilities. In this case, Security Controller makes a description of the required capabilities by using the NSF capability information sub-model in Section 4.1.1, and sends DMS a query about which NSF(s) can provide these capabilities.¶
The I2NSF registration interface is used for the following purposes.
Developer's Management System (DMS) registers NSFs and their capabilities into Security Controller
via the registration interface. In case that Security Controller fails to find any NSF among the registered
NSFs which can provide some required capabilities, Security Controller uses the registration interface
to query DMS about NSF(s) having the required capabilities.
The following sections describe the YANG data models to support these operations.¶
This section expands the i2nsf-nsf-registrations in Figure 5.¶
When registering an NSF to Security Controller, DMS uses this module to describe what capabilities the NSF can offer.
DMS includes the network access information of the NSF which is required to make a network connection with the NSF as
well as the capability description of the NSF.¶
This section expands the nsf-capability-query in Figure 5.¶
Security Controller MAY require some additional capabilities to provide the security service requested by an I2NSF user,
but none of the registered NSFs has the required capabilities. In this case, Security Controller makes a description of
the required capabilities using this module and then queries DMS about which NSF(s) can provide these capabilities.
Use NETCONF RPCs to send a NSF capability query. Input data is query-i2nsf-capability-info and output data is nsf-access-info.
In Figure 7, the ietf-i2nsf-capability refers to the module defined in [I-D.ietf-i2nsf-capability-data-model].¶
This document requests IANA to register the following YANG
module in the "YANG Module Names" registry
Reference: RFC XXXX
// RFC Ed.: replace XXXX with actual RFC number and remove
// this note
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 NETCONF layer is the secure transport layer, and the required secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the required secure transport is TLS [RFC8446].¶
The NETCONF access control model [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 content.¶
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes MAY be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:¶
nsf-registrations: The attacker MAY exploit this to register a compromised or malicious NSF instead of a legitimate NSF with the Security Controller.¶
nsf-performance-capability: The attacker MAY provide incorrect information of the performance capability of any target NSF by illegally modifying this.¶
nsf-capability-info: The attacker MAY provide incorrect information of the security capability of any target NSF by illegally modifying this.¶
nsf-access-info: The attacker MAY provide incorrect network access information of any target NSF by illegally modifying this.¶
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 and their sensitivity/vulnerability:¶
nsf-registrations: The attacker MAY try to gather some sensitive information of a registered NSF by sniffing this.¶
nsf-performance-capability: The attacker MAY gather the performance capability information of any target NSF and misuse the information for subsequent attacks.¶
nsf-capability-info: The attacker MAY gather the security capability information of any target NSF and misuse the information for subsequent attacks.¶
nsf-access-info: The attacker MAY gather the network access information of any target NSF and misuse the information for subsequent attacks.¶
The RPC operation in this YANG module MAY be considered sensitive or vulnerable in some network environments. It is thus important to control access to this operation. The following is the operation and its sensitivity/vulnerability:¶
nsf-capability-query: The attacker MAY exploit this RPC operation to deteriorate the availability of the DMS and/or gather the information of some interested NSFs from the DMS.¶
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
Wang, L., Chen, M., Dass, A., Ananthakrishnan, H., Kini, S., and N. Bahadur, "A YANG Data Model for the Routing Information Base (RIB)", RFC 8431, DOI 10.17487/RFC8431, , <https://www.rfc-editor.org/info/rfc8431>.
Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, L., Sridhar, T., Bursell, M., and C. Wright, "Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, DOI 10.17487/RFC7348, , <https://www.rfc-editor.org/info/rfc7348>.
Marin-Lopez, R., Lopez-Millan, G., and F. Pereniguez-Garcia, "A YANG Data Model for IPsec Flow Protection Based on Software-Defined Networking (SDN)", RFC 9061, DOI 10.17487/RFC9061, , <https://www.rfc-editor.org/info/rfc9061>.
This section shows an XML example for querying the capabilities of a time-based firewall
in either IPv4 networks [RFC5737] or IPv6 networks [RFC3849].¶
Figure 22 shows the XML configuration for querying the capabilities of a time-based firewall in an IPv4 network [RFC5737].
The access information of the announced time-based firewall has the IPv4 address of
192.0.2.11 and the port number of 49152.¶
In addition, Figure 23 shows the XML configuration for querying the capabilities of a time-based firewall in an IPv6 network [RFC3849].
The access information of the announced time-based firewall has the IPv6 address of
2001:db8:0:1::11 and the port number of 49152.¶
Network Functions Virtualization (NFV) can be used to implement I2NSF framework. In NFV environments, NSFs are deployed as virtual network functions (VNFs). Security Controller can be implemented as an Element Management (EM) of the NFV architecture, and is connected with the VNF Manager (VNFM) via the Ve-Vnfm interface [nfv-framework]. Security Controller can use this interface for the purpose of the lifecycle management of NSFs. If some NSFs need to be instantiated to enforce security policies in the I2NSF framework, Security Controller could request the VNFM to instantiate them through the Ve-Vnfm interface. Or if an NSF, running as a VNF, is not used by any traffic flows for a time period, Security Controller MAY request deinstantiating it through the interface for efficient resource utilization.¶
This document is a product by the I2NSF Working Group (WG) including
WG Chairs (i.e., Linda Dunbar and Yoav Nir) and Diego Lopez.
This document took advantage of the review and comments from the following people:
Roman Danyliw, Reshad Rahman (YANG doctor), and Tom Petch.
We authors sincerely appreciate their sincere efforts and kind help.¶
This work was supported by Institute of Information &
Communications Technology Planning & Evaluation (IITP) grant funded by
the Korea MSIT (Ministry of Science and ICT) (No. 2016-0-00078, Cloud Based
Security Intelligence Technology Development for the Customized
Security Service Provisioning).
This work was supported in part by the IITP (2020-0-00395, Standard
Development of Blockchain based Network Management Automation Technology).¶