Internet-Draft | Application Interface YANG Data Model | April 2022 |
Lingga, et al. | Expires 30 October 2022 | [Page] |
This document describes an information model and a YANG data model for the Application Interface between an Interface to Network Security Functions (I2NSF) Analyzer and a Security Controller in an I2NSF system in a Network Functions Virtualization (NFV) environment. The YANG data model described in this document is based on the I2NSF NSF-Facing Interface and the I2NSF Monitoring Interface for enabling feedback delivery based on the information received from a Network Security Function (NSF).¶
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In Interface to Network Security Functions (I2NSF) [RFC8329], the Monitoring Interface [I-D.ietf-i2nsf-nsf-monitoring-data-model] is defined as an interface to collect information (e.g., network statistics, resources) from NSF(s). The information can be received by a query or a report. In a query-based, the information is obtained by a request from a client (I2NSF Analyzer). But in a report-based, the information is provided by a server (NSFs) when the notification or alarm is triggered by an event. In this model, the report-based collection information is used for realizing the Security Management Automation (SMA) in cloud-based security services [I-D.jeong-i2nsf-security-management-automation]. as the information is sent automatically by the NSFs. Figure 1 shows the I2NSF Framework for Security Management Automation.¶
The automatic reports by the NSFs are collected in a single instance (i.e., I2NSF Analyzer) to be analyzed. By analyzing the information, a new security policy can be produced to further enhance the security of the network. To create the automated system, the analyzer should be done automatically with the help of machine learning. The automated analyzer is not in the scope of this document.¶
The new security policy needs to be delivered from the I2NSF Analyzer to the Security Controller so the new policy can be listed and monitored properly. For that purpose, this document introduces the Application Interface as the intermediary between the I2NSF Analyzer and the Security Controller. Then the policy should be delivered directly to the NSFs by the Security Controller via the NSF-Facing Interface [I-D.ietf-i2nsf-nsf-facing-interface-dm].¶
The purpose of this document is to provide a standard for a feedback interface in an I2NSF Framework called Application Interface. With the provided Application Interface, the realization of Security Management Automation (SMA) should be possible.¶
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] and adopts the Network Management Datastore Architecture (NMDA). The meaning of the symbols in tree diagrams is defined in [RFC8340].¶
This document introduces Application Interface as an interface to deliver a report of the augmentation or generation of security policy rules created by I2NSF Analyzer to Security Controller [I-D.jeong-i2nsf-security-management-automation]. This allows Security Controller to actively reinforce the network with its security policy management. Figure 2 shows the high-level concept of Application Interface such as Policy Reconfiguration and Feedback Information.¶
Both policy reconfiguration and feedback information provide the following high-level abstraction:¶
Policy reconfiguration is the rearrangement of a security policy in a different form or combination of the existing security policy to enhance the security service in the network. A policy reconfiguration is generated by the I2NSF Analyzer after receiving and analyzing monitoring information of NSF Events from an NSF [I-D.ietf-i2nsf-nsf-monitoring-data-model].¶
Policy reconfiguration works together with the three I2NSF interfaces defined for the I2NSF Framework, i.e., NSF-Facing Interface [I-D.ietf-i2nsf-nsf-facing-interface-dm], NSF Monitoring Interface [I-D.ietf-i2nsf-nsf-monitoring-data-model], and Application Interface, to create a closed-loop system for reinforcing the network security. Figure 3 shows an illustration of the closed-loop system for the I2NSF Framework.¶
Figure 3 shows a closed-loop system between Security Controller, NSF, and I2NSF Analyzer. The Security Controller delivers a security policy to an appropriate NSF via the NSF-Facing Interface [I-D.ietf-i2nsf-nsf-facing-interface-dm]. The NSF will prepare for a security service according to the given configuration and provide a security service for the network. The NSF SHOULD also provide monitoring information (e.g., NSF Events and System Alarms) to be analyzed. This monitoring information can be delivered from the NSF to an I2NSF Analyzer via the Monitoring Interface [I-D.ietf-i2nsf-nsf-monitoring-data-model]. Then the I2NSF Analyzer analyzes the monitoring information for the reconfiguration of an existing security policy, the generation of a new security policy, and the feedback for security system management (e.g., the scaling-up or scaling-down of resources related to NSFs). To fully automate the closed-loop system, the I2NSF Analyzer should analyze the monitoring information automatically using machine learning techniques (e.g., Deep Learning [Deep-Learning]). The results of the analysis may trigger the reconfiguration of an existing security policy or the generation of a new security policy to strengthen the network security. The reconfiguration or configuration request will be delivered from the I2NSF Analyzer to the Security Controller via the Application Interface.¶
To realize the closed-loop system, the Application Interface needs to properly follow the similar guidelines for the I2NSF Framework [RFC8329]. The Application Interface follows [I-D.ietf-i2nsf-nsf-facing-interface-dm] to create a security policy to reconfigure an existing security policy of NSF(s) or to generate a new security policy.¶
Application Interface holds a list of security policies so that the (re)configuration of a security policy and the feedback information can be provided to the Security Controller. Each policy consists of a list of rule to be enhanced on the NSF. Note that the synchronization of the list of security policies should be done between the Security Controller and the I2NSF Analyzer and the specific mechanism is out of the scope of this document. A (re)configured security policy rule should be able to cope with attacks or failures that can happen to the network in near future. Such a rule is reconfigured or generated by the I2NSF Analyzer to tackle a detected problem in the network. It uses the Event-Condition-Action (ECA) model as the basis for the design of I2NSF Policy (Re)configuration as described in [RFC8329] and [I-D.ietf-i2nsf-capability-data-model].¶
An example of Policy (Re)configuration is a DDoS Attack that is detected by a DDoS Mitigator. The DDoS Mitigator creates monitoring information and delivers it to the I2NSF Analyzer. The I2NSF Analyzer analyzes the information and generates a new policy to handle the DDoS Attack, such as a firewall rule to drop all packets from the source of the DDoS Attack.¶
The YANG tree structure for policy reconfiguration is provided through the augmentation of the NSF-Facing Interface YANG Module [I-D.ietf-i2nsf-nsf-facing-interface-dm] as follows:¶
The policy reconfiguration must include the following information:¶
Feedback information is information about problem(s) of an NSF for a security service such as system resource over-usage or malfunction. This problem cannot be handled by creating a new policy. In the similar way with policy reconfiguration, the feedback information should be delivered from the I2NSF Analyzer to the Security Controller that will be able to handle the reported problem(s).¶
Figure 5 shows the handling of feedback information. For feedback information, the given feedback is not a security policy, hence the Security Controller needs to take an action to handle the reported problem(s). The action includes the report to the I2NSF User and the query of the system resource management of the relevant NSF(s) to the Developer's Management System (DMS). DMS will communicate with the Management and Orchestration (MANO) Unit in the Network Functions Virtualization (NFV) Framework to deal with the system management issue(s) of the relevant NSFs [I-D.ietf-i2nsf-applicability]. The details of the handling process are out of the scope of this document.¶
The YANG tree structure for feedback information is provided with the use of the NSF Monitoring Interface YANG Module [I-D.ietf-i2nsf-nsf-monitoring-data-model] as follows:¶
Figure 6 shows the high-level abstraction of Feedback Information. The feedback information should include:¶
This section shows the YANG module of Application Interface. The YANG module in this document is referencing to [RFC6991] [I-D.ietf-i2nsf-nsf-facing-interface-dm] [I-D.ietf-i2nsf-nsf-monitoring-data-model].¶
The YANG module makes references to [RFC5646] [RFC6265] [RFC8343] [I-D.ietf-httpbis-semantics]¶
This document requests IANA to register the following URI in the "IETF XML Registry" [RFC3688]:¶
URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-feedback-policy Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace.¶
This document requests IANA to register the following YANG module in the "YANG Module Names" registry [RFC7950][RFC8525]:¶
name: ietf-i2nsf-feedback-policy namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-feedback-policy prefix: nsffb reference: RFC XXXX // RFC Ed.: replace XXXX with an actual RFC number and remove // this note.¶
This section shows XML configuration examples of feedback policy rules that are delivered from the I2NSF Analyzer to the Security Controller over the Application Interface after the I2NSF Analyzer analyzes the Monitoring Information.¶
In this example, the scenario can be seen in Figure 8.¶
In this scenario, a DDoS Mitigator detects a DDoS Attack and sends a notification to the I2NSF Analyzer as shown in Figure 9.¶
In the scenario shown in Figure 9, the description of the XML example is as follows:¶
After receiving the information, the I2NSF Analyzer analyzes the data and creates a new feedback policy to enforce the security of the network. The I2NSF Analyzer delivers a feedback policy to the Security Controller as shown in Figure 10.¶
The policy reconfiguration in Figure 10 means the following:¶
In this scenario, an NSF is overloaded and sends a notification to the I2NSF Analyzer as shown in Figure 11.¶
In the scenario shown in Figure 11, the description of the XML example is as follows:¶
After receiving the information, the I2NSF Analyzer analyzes the data and creates a new feedback policy to solve the problem that is detected in the NSF. The I2NSF Analyzer delivers a feedback information to the Security Controller as shown in Figure 12.¶
The feedback information in Figure 12 means the following:¶
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. And the data model in this document uses the data model from NSF-Facing Interface data model, it MUST follow the Security Considerations mentioned in the [I-D.ietf-i2nsf-nsf-facing-interface-dm].¶
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. This document also MUST follow the Security Considerations about the readable data nodes mentioned in the [I-D.ietf-i2nsf-nsf-facing-interface-dm].¶
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 experts: Roman Danyliw and Tom Petch. The 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) (2020-0-00395, Standard Development of Blockchain based Network Management Automation Technology). This work was supported in part by the IITP (R-20160222-002755, Cloud based Security Intelligence Technology Development for the Customized Security Service Provisioning). This work was supported in part by the MSIT under the Information Technology Research Center (ITRC) support program (IITP-2022-2017-0-01633) supervised by the IITP.¶
The following are co-authors of this document:¶
Jeonghyeon Kim - Department of Electrical and Computer Engineering, Sungkyunkwan University, 2066 Seobu-ro Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea, EMail: jeonghyeon12@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¶
Younghan Kim - School of Electronic Engineering, Soongsil University, 369, Sangdo-ro, Dongjak-gu, Seoul 06978, Republic of Korea, EMail: younghak@ssu.ac.kr¶
The following changes are made from draft-lingga-i2nsf-application-interface-dm-02:¶