Network Working Group L. Xia
Internet-Draft D. Zhang
Intended status: Experimental Huawei
Expires: September 14, 2017 Y. Wu
Aliababa Group
R. Kumar
A. Lohiya
Juniper Networks
H. Birkholz
Fraunhofer SIT
March 13, 2017

An Information Model for the Monitoring of Network Security Functions (NSF)


The Network Security Functions (NSF) NSF-facing interface exists between the Service Provider's management system (or Security Controller) and the NSFs to enforce the security policy provisioning and network security status monitoring . This document focuses on the monitoring part of it and proposes the information model for it.

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Table of Contents

1. Introduction

According to [I-D.ietf-i2nsf-framework], the interface provided by a NSF (e.g., FW, IPS, Anti-DDOS, or Anti-Virus) to administrative entities (e.g., NMS, security controller) for configuring security function in the NSF and monitoring the NSF is referred to as a 'I2NSF customer-facing interface'. The monitoring part of it is meant to monitor the NSF e.g. events, alerts, alarms, logs, counters. The monitoring of the NSF plays a very important role in the overall security framework if done in a timely and comprehensive way. The monitoring information generated by a NSF could very well be an early indication of malicious activity, or anomalous behavior, or a potential sign of denial of service attacks.

This draft proposes a comprehensive NSF monitoring information model that provide visibility into NSFs. This document will not go into the design details of NSF-facing interface. Instead, this draft is focused on specifying the information that a NSF needs to provide in the monitoring part of the NSF-facing interface, as well as its information model. Besides, [I-D.draft-xibassnez-i2nsf-capability ] specifies the information model for the security policy provisioning part of the NSF-facing interface.

2. Terminology

2.1. Key Words

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

2.2. Definition of Terms

This document uses the terms defined in [I-D.draft-ietf-i2nsf-terminology].

3. Use cases for NSF Monitoring Data

As mentioned earlier, monitoring plays a very critical role in the overall security framework. The monitoring of the NSF provides very valuable information to the security controller in maintaining the provisioned security posture. Besides this, there are various other reasons to monitor the NSFs as listed below:

4. Classification of NSF Monitoring Data

In order to maintain a strong security posture, it is not only necessary to configure NSF security policies but also to continuously monitor NSF by consuming acquirable monitoring data. This enables security admins to assess what is happening in the network timely. It is not possible to block all the internal and external threats based on static security posture but requires a very dynamic posture with constant visibility. This draft defines a set of information elements (and their scope) that can be acquired from NSF and can be used as monitoring data. In essence, these types of monitoring data can be leveraged to support constant visibility on multiple levels of granularity and can be consumed by corresponding functions. The types of monitoring data as ordered below increase in expressiveness by incorporating more information to the semantics of the monitoring data. There are two categories of monitoring data. Information that is produced and emitted by an NSF automatically (published data) and information that is produced and retained by the NSF and has to be collected in intervals (retained data):

Published Data:

Retained Data:

5. Exporting NSF Monitoring Data

As per the use cases of NSF monitoring data, the data need to be sent to various consumers based on the needs and requirements. There are multiple things to be considered for exporting this data to needed parties as listed below:

6. Basic Information Model for All Monitoring Data

As explained in the above section, there is a wealth of data available from the NSF that can be monitored. Firstly, there must be some general information with each monitoring message sent from an NSF that helps consumer in identifying meta data with that message, which are listed as below:

7. Extended Information Model for Monitoring Data

This section covers the additional information associated with the system messages. The extended information model is only for the structured data such as alarm. Any unstructured data is specified with basic information model only.

[Editors' note]: This section remains the same as -02 version, although the classification of the monitoring data has been changed from -02 version. The new inconsistency will be addressed in next verion.

7.1. System Alarm

7.1.1. Memory Alarm

The following information should be included in a Memory Alarm:

7.1.2. CPU Alarm

The following information should be included in a CPU Alarm:

7.1.3. Disk Alarm

The following information should be included in a Disk Alarm:

7.1.4. Hardware Alarm

The following information should be included in a Hardware Alarm:

7.1.5. Interface Alarm

The following information should be included in a Interface Alarm:

7.2. System Events

7.2.1. Access Violation

The following information should be included in this event:

7.2.2. Configuration Change

The following information should be included in this event:

7.3. System Log

7.3.1. Access Logs

Access logs record administrators' login, logout, and operations on the device. By analyzing them, security vulnerabilities can be identified. The following information should be included in operation report:

7.3.2. Resource Utilization Logs

Running reports record the device system's running status, which is useful for device monitoring. The following information should be included in running report:

7.3.3. User Activity Logs

User activity logs provide visibility into users' online records (such as login time, online/lockout duration, and login IP addresses) and the actions users perform. User activity reports are helpful to identify exceptions during user login and network access activities.

7.4. System Counters

7.4.1. Interface counters

Interface counters provide visibility into traffic into and out of NSF, bandwidth usage.

7.5. NSF Events

7.5.1. DDoS Event

The following information should be included in a DDoS Event:

7.5.2. Session Table Event

The following information should be included in a Session Table Event:

7.5.3. Virus Event

The following information should be included in a Virus Event:

7.5.4. Intrusion Event

The following information should be included in a Intrustion Event:

7.5.5. Botnet Event

The following information should be included in a Botnet Event:

7.5.6. Web Attack Event

The following information should be included in a Web Attack Alarm:

7.6. NSF Logs

7.6.1. DDoS Logs

Besides the fields in an DDoS Alarm, the following information should be included in a DDoS Logs:

7.6.2. Virus Logs

Besides the fields in an Virus Alarm, the following information should be included in a Virus Logs:

7.6.3. Intrusion Logs

Besides the fields in an Intrusion Alarm, the following information should be included in a Intrusion Logs:

7.6.4. Botnet Logs

Besides the fields in an Botnet Alarm, the following information should be included in a Botnet Logs:

7.6.5. DPI Logs

DPI Logs provide statistics on uploaded and downloaded files and data, sent and received emails, and alert and block records on websites. It's helpful to learn risky user behaviors and why access to some URLs is blocked or allowed with an alert record.

7.6.6. Vulnerabillity Scanning Logs

Vulnerability scanning logs record the victim host and its related vulnerability information that should to be fixed. the following information should be included in the report:

7.6.7. Web Attack Logs

Besides the fields in an Web Attack Alarm, the following information should be included in a Web Attack Report:

7.7. NSF Counters

7.7.1. Firewall counters

Firewall counters provide visibility into traffic signatures, bandwidth usage, and how the configured security and bandwidth policies have been applied.

7.7.2. Policy Hit Counters

Policy Hit Counters record the security policy that traffic matches and its hit count. It can check if policy configurations are correct.

8. IANA Considerations

This document makes no request of IANA.

Note to RFC Editor: this section may be removed on publication as an RFC.

9. Security Considerations

The monitoring information of NSF should be protected by the secure communication channel, to ensure its confidentiality and integrity. In another side, the NSF and security controller can all be faked, which lead to undesireable results, i.e., leakage of NSF's important operational information, faked NSF sending false information to mislead security controller. The mutual authentication is essential to protected against this kind of attack. The current mainstream security technologies (i.e., TLS, DTLS, IPSEC, X.509 PKI) can be employed approriately to provide the above security functions.

In addition, to defend against the DDoS attack caused by a lot of NSFs sending massive monitoring information to the security controller, the rate limiting or similar mechanisms should be considered in NSF and security controller, whether in advance or just in the process of DDoS attack.

10. Acknowledgements

11. References

11.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3877] Chisholm, S. and D. Romascanu, "Alarm Management Information Base (MIB)", RFC 3877, DOI 10.17487/RFC3877, September 2004.
[RFC4765] Debar, H., Curry, D. and B. Feinstein, "The Intrusion Detection Message Exchange Format (IDMEF)", RFC 4765, DOI 10.17487/RFC4765, March 2007.

11.2. Informative References

[I-D.ietf-i2nsf-framework] Lopez, D., Lopez, E., Dunbar, L., Strassner, J. and R. Kumar, "Framework for Interface to Network Security Functions", Internet-Draft draft-ietf-i2nsf-framework-04, October 2016.
[I-D.xia-i2nsf-capability-interface-im] Xia, L., Strassner, J., Li, K., Zhang, D., Lopez, E., Bouthors, N. and L. Fang, "Information Model of Interface to Network Security Functions Capability Interface", Internet-Draft draft-xia-i2nsf-capability-interface-im-06, July 2016.

Authors' Addresses

Liang Xia Huawei EMail:
Dacheng Zhang Huawei EMail:
Yi Wu Aliababa Group EMail:
Rakesh Kumar Juniper Networks EMail:
Anil Lohiya Juniper Networks EMail:
Henk Birkholz Fraunhofer SIT EMail: