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:¶
1)
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.¶
2)
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: Directional
Capabilities, Event Capabilities, Condition Capabilities,
Action Capabilities, Resolution Strategy Capabilities,
Default Action Capabilities. 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 following that
are required to communicate with an NSF through NETCONF [RFC6241]
or RESTCONF [RFC8040]:
an IP address (i.e., IPv4 or IPv6 address) and a port number.
Note that TCP is used as a transport layer protocol due to either
NETCONF or RESTCONF. In this document, NSF Access Information is
used to identify a specific NSF instance. That is, NSF Access
Information is the signature (i.e., unique identifier) of an
NSF instance in the overall I2NSF 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.¶
A simplified graphical representation of the data model is
used in this section. The meaning of the symbols used in
the following diagrams [RFC8431] is as
follows:¶
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 section expands the nsf-capability-info in Figure 6 and Figure 7.¶
In Figure 8,
the ietf-i2nsf-capability refers to the module defined in
[I-D.ietf-i2nsf-capability-data-model].
The performance-capability is used to specify the
performance capability of an NSF.¶
This section expands the nsf-access-info in Figure 6.¶
This module contains the network access information of an
NSF that is required to enable network communications with
the NSF. The field of ip can have either an IPv4 address
or an IPv6 address.¶
This section provides a YANG module of the data model for
the registration interface between Security Controller and
Developer's Management System, as defined in
Section 4.¶
This document requests IANA to register the following YANG
module in the "YANG Module Names" registry
[RFC7950][RFC8525]:¶
Name: ietf-i2nsf-registration-interface
Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-registration-interface
Prefix: i2nsfri
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.¶
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", DOI 10.17487/RFC2119, BCP 14, RFC 2119, , <https://www.rfc-editor.org/info/rfc2119>.
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", DOI 10.17487/RFC6241, RFC 6241, , <https://www.rfc-editor.org/info/rfc6241>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", DOI 10.17487/RFC8174, RFC 8174, BCP 14, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8329]
Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R. Kumar, "Framework for Interface to Network Security Functions", DOI 10.17487/RFC8329, RFC 8329, , <https://www.rfc-editor.org/info/rfc8329>.
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", RFC 8341, DOI 10.17487/RFC8341, STD 91, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8342]
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>.
[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>.
[RFC8431]
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>.
Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K., and R. Wilton, "YANG Library", DOI 10.17487/RFC8525, RFC 8525, , <https://www.rfc-editor.org/info/rfc8525>.
Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix Reserved for Documentation", DOI 10.17487/RFC3849, RFC 3849, , <https://www.rfc-editor.org/info/rfc3849>.
[RFC5737]
Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks Reserved for Documentation", RFC 5737, DOI 10.17487/RFC5737, , <https://www.rfc-editor.org/info/rfc5737>.
[RFC7348]
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>.
This section shows XML examples of the I2NSF Registration
Interface data model for registering the capabilities in
either IPv4 networks [RFC5737] or IPv6
networks [RFC3849] with Security Controller.¶
Figure 12 shows the
configuration XML for registering a general firewall in an
IPv4 network [RFC5737] and its capabilities
as follows.¶
The instance name of the NSF is general_firewall.¶
The NSF can inspect IPv4 protocol header field, source
address(es), and destination address(es).¶
The NSF can inspect the port number(s) for the transport
layer protocol, i.e., TCP.¶
The NSF can determine whether the packets are allowed to
pass, drop, or mirror.¶
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 (2020-0-00395-003, Standard
Development of Blockchain based Network Management Automation Technology).¶
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¶
Jinyong (Tim) Kim -
Department of Electronic, Electrical and Computer Engineering,
Sungkyunkwan University,
2066 Seo-ro Jangan-gu,
Suwon, Gyeonggi-do 16419,
Republic of Korea.
EMail: timkim@skku.edu¶
Chaehong Chung -
Department of Electronic, Electrical and Computer Engineering,
Sungkyunkwan University,
2066 Seo-ro Jangan-gu,
Suwon, Gyeonggi-do 16419,
Republic of Korea.
EMail: darkhong@skku.edu¶
Susan Hares -
Huawei,
7453 Hickory Hill,
Saline, MI 48176,
USA.
EMail: shares@ndzh.com¶
Diego R. Lopez -
Telefonica I+D,
Jose Manuel Lara, 9,
Seville, 41013,
Spain.
EMail: diego.r.lopez@telefonica.com¶