Network Working Group                                             L. Xia
Internet-Draft                                                  D. Zhang
Intended status: Experimental                                     Huawei
Expires: April 27, 2019                                            Y. Wu
                                                          Aliababa Group
                                                                R. Kumar
                                                               A. Lohiya
                                                        Juniper Networks
                                                             H. Birkholz
                                                          Fraunhofer SIT
                                                        October 24, 2018


 An Information Model for the Monitoring of Network Security Functions
                                 (NSF)
               draft-zhang-i2nsf-info-model-monitoring-07

Abstract

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

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 April 27, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Key Words . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Definition of Terms . . . . . . . . . . . . . . . . . . .   4
   3.  Use cases for NSF Monitoring Data . . . . . . . . . . . . . .   4
   4.  Classification of NSF Monitoring Data . . . . . . . . . . . .   5
     4.1.  Retention and Emission  . . . . . . . . . . . . . . . . .   5
     4.2.  Notifications and Events  . . . . . . . . . . . . . . . .   6
     4.3.  Unsolicited Poll and Solicited Push . . . . . . . . . . .   7
     4.4.  I2NSF Monitoring Terminology for Retained Information . .   8
   5.  Conveyance of NSF Monitoring Information  . . . . . . . . . .   8
     5.1.  Information Types and Acquisition Methods . . . . . . . .   9
   6.  Basic Information Model for All Monitoring Data . . . . . . .  10
   7.  Extended Information Model for Monitoring Data  . . . . . . .  10
     7.1.  System Alarm  . . . . . . . . . . . . . . . . . . . . . .  11
       7.1.1.  Memory Alarm  . . . . . . . . . . . . . . . . . . . .  11
       7.1.2.  CPU Alarm . . . . . . . . . . . . . . . . . . . . . .  11
       7.1.3.  Disk Alarm  . . . . . . . . . . . . . . . . . . . . .  11
       7.1.4.  Hardware Alarm  . . . . . . . . . . . . . . . . . . .  12
       7.1.5.  Interface Alarm . . . . . . . . . . . . . . . . . . .  12
     7.2.  System Events . . . . . . . . . . . . . . . . . . . . . .  12
       7.2.1.  Access Violation  . . . . . . . . . . . . . . . . . .  13
       7.2.2.  Configuration Change  . . . . . . . . . . . . . . . .  13
     7.3.  System Log  . . . . . . . . . . . . . . . . . . . . . . .  13
       7.3.1.  Access Logs . . . . . . . . . . . . . . . . . . . . .  14
       7.3.2.  Resource Utilization Logs . . . . . . . . . . . . . .  14
       7.3.3.  User Activity Logs  . . . . . . . . . . . . . . . . .  15
     7.4.  System Counters . . . . . . . . . . . . . . . . . . . . .  15
       7.4.1.  Interface counters  . . . . . . . . . . . . . . . . .  15
     7.5.  NSF Events  . . . . . . . . . . . . . . . . . . . . . . .  16
       7.5.1.  DDoS Event  . . . . . . . . . . . . . . . . . . . . .  16
       7.5.2.  Session Table Event . . . . . . . . . . . . . . . . .  17
       7.5.3.  Virus Event . . . . . . . . . . . . . . . . . . . . .  17
       7.5.4.  Intrusion Event . . . . . . . . . . . . . . . . . . .  18
       7.5.5.  Botnet Event  . . . . . . . . . . . . . . . . . . . .  19
       7.5.6.  Web Attack Event  . . . . . . . . . . . . . . . . . .  20



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     7.6.  NSF Logs  . . . . . . . . . . . . . . . . . . . . . . . .  21
       7.6.1.  DDoS Logs . . . . . . . . . . . . . . . . . . . . . .  21
       7.6.2.  Virus Logs  . . . . . . . . . . . . . . . . . . . . .  22
       7.6.3.  Intrusion Logs  . . . . . . . . . . . . . . . . . . .  22
       7.6.4.  Botnet Logs . . . . . . . . . . . . . . . . . . . . .  22
       7.6.5.  DPI Logs  . . . . . . . . . . . . . . . . . . . . . .  23
       7.6.6.  Vulnerabillity Scanning Logs  . . . . . . . . . . . .  24
       7.6.7.  Web Attack Logs . . . . . . . . . . . . . . . . . . .  24
     7.7.  NSF Counters  . . . . . . . . . . . . . . . . . . . . . .  25
       7.7.1.  Firewall counters . . . . . . . . . . . . . . . . . .  25
       7.7.2.  Policy Hit Counters . . . . . . . . . . . . . . . . .  26
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  27
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  27
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  27
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  27
     10.2.  Informative References . . . . . . . . . . . . . . . . .  28
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  29
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  29

1.  Introduction

   According to [I-D.ietf-i2nsf-terminology], the interface provided by
   an NSF (e.g., FW, IPS, Anti-DDOS, or Anti-Virus function) to
   administrative entities (e.g., NMS, security controller) to enable
   remote management (i.e. configuring and monitoring) is referred to as
   an "I2NSF NSF-Facing Interface".  Monitoring procedures intent to
   acquire vital types of data at rest with respect to NSF, e.g. alarms,
   records, or counters, via data in motion, e.g. queries,
   notifications, or events.  The monitoring of NSF plays an important
   role in the overall security framework, if done in a timely and
   comprehensive way.  The monitoring information generated by an NSF
   can very well be an early indication of anomalous behavior or
   malicious activity, such as denial of service attacks.

   This draft defines a comprehensive NSF monitoring information model
   that provides visibility into NSF.  This document will not go into
   the design details of NSF-Facing Interfaces.  Instead, it is focused
   on specifying the information and illustrates the methods that enable
   NSF to provide the information required in order to be monitored in a
   scalable and efficient way via the NSF-Facing Interface.  The
   information model for monitoring presented in this document is a
   complement to the information model for the security policy
   provisioning part of the NSF-Facing Interface specified in
   [I-D.xibassnez-i2nsf-capability].







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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.ietf-i2nsf-terminology].

3.  Use cases for NSF Monitoring Data

   As mentioned earlier, monitoring plays a 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 NSF as listed below:

   o  The security administrator can configure a policy that is
      triggered on a specific event occurring in the NSF or the network.
      If a security controller detects the specified event, it
      configures additional security functions as defined by policies.

   o  The events triggered by NSF as a result of security policy
      violation can be used by SIEM to detect any suspicious activity in
      a larger correlation context.

   o  The events and activity logs from NSF can be used to build
      advanced analytics, such as behavior and predictive models to
      improve security posture in large deplyoments.

   o  The security controller can use events from the NSF for achieving
      high availability.  It can take corrective actions such as
      restarting a failed NSF, horizontally scaling the NSF, etc.

   o  The events and activity logs from the NSF can aid in the root
      cause analysis of an operational issue - therefore improve
      debugging.

   o  The activity logs from the NSF can be used to build historical
      data for operational and business reasons.








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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 and therefore observable
   information.  This enables security admins to assess the state of the
   network topology in a timely fashion.  It is not possible to block
   all the internal and external threats based on static security
   posture.  A more practical approach is supported by enabling dynamic
   security measures - for which continuous visibility is required.
   This draft defines a set of information elements (and their scope)
   that can be acquired from NSF and can be used as monitoring
   information.  In essence, these types of monitoring information can
   be leveraged to support constant visibility on multiple levels of
   granularity and can be consumed by corresponding functions.

   Three basic domains about the monitoring of information originating
   from a system entity [RFC4949] or a NSF are highlighted in this
   document.

   o  Retention and Emission

   o  Notifications and Events

   o  Unsolicited Poll and Solicited Push

   The Alarm Management Framework in [RFC3877] defines an Event as
   "something that happens which may be of interest.  A fault, a change
   in status, crossing a threshold, or an external input to the system,
   for example."  In the I2NSF domain, I2NSF events
   [I-D.ietf-i2nsf-terminology] are created and the scope of the Alarm
   Management Framework Events is still applicable due to its broad
   definition.  The model presented in this document elaborates on the
   work-flow of creating I2NSF events in the context of NSF monitoring
   and on how initial I2NSF events are created.

   As with I2NSF components, every generic system entity can include a
   set of capabilities [I-D.ietf-i2nsf-terminology] that creates
   information about the context, composition, configuration, state or
   behavior of that system entity.  This information is intended to be
   provided to other consumers of informations--and in the scope of this
   document, to monitor that information in an automated fashion.

4.1.  Retention and Emission

   Typically, a system entity populates standardized interface, such as
   SNMP, NETCONF, RESTCONF or CoMI to provide and emit created
   information directly via NSF-Facing Interfaces



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   [I-D.ietf-i2nsf-terminology].  Alternatively, the created information
   is retained inside the system entity (or hierarchy of system entities
   in a composite device) via records or counters that are not exposed
   directly via NSF-Facing Interfaces.

   Information emitted via standardized interfaces can be consumed by an
   I2NSF Agent [I-D.ietf-i2nsf-terminology] that includes the capability
   to consume information not only via I2NSF Interfaces but also via
   interfaces complementary to the standardized interfaces a generic
   system entity provides.

   Information retained on a system entity requires a corresponding
   I2NSF Agent to access aggregated records of information, typically in
   the form of logfiles or databases.  There are ways to aggregate
   records originating from different system entities over a network,
   for examples via Syslog [RFC5424] or Syslog over TCP [RFC6587].  But
   even if records are conveyed, the result is the same kind of
   retention in form of a bigger aggregate of records on another system
   entity.

   An I2NSF Agent is required to process fresh [RFC4949] records created
   by I2NSF Functions in order to provide them to other I2NSF Components
   via corresponding I2NSF Interfaces timely.  This process is
   effectively based on homogenizing functions that can access and
   convert specific kinds of records into information that can be
   provided and emitted via I2NSF interfaces.

   Retained or emitted, the information required to support monitoring
   processes has to be processed by an I2NSF Agent at some point in the
   work-flow.  Typical locations of these I2NSF Agents are:

   o  a system entity that creates the information

   o  a system entity that retains an aggregation of records

   o  an I2NSF Component that includes the capabilities of using
      standardized interfaces provided by other system entities that are
      not I2NSF Components

   o  an I2NSF Component that creates the information

4.2.  Notifications and Events

   A specific task of I2NSF Agents is to process I2NSF Policy Rules
   [I-D.ietf-i2nsf-terminology].  Rules are composed of three clauses:
   Events, Conditions, and Actions.  In consequence, an I2NSF Event is
   required to trigger an I2NSF Policy Rule.  "An I2NSF Event is defined
   as any important occurrence in time of a change in the system being



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   managed, and/or in the environment of the system being managed."
   [I-D.ietf-i2nsf-terminology], which aligns well with the generic
   definition of Event from [RFC3877].

   The model illustrated in this document introduces a complementary
   type of information that can be conveyed--notification.

   Notification:  An occurrence of a change of context, composition,
      configuration, state or behavior of a system entity that can be
      directly or indirectly observed by an I2NSF Agent and can be used
      as input for an event-clause in I2NSF Policy Rules.

      A notification is similar to an I2NSF Event with the exception
      that it is created by a system entity that is not an I2NSF
      Component and that its importances is yet to be assessed.
      Semantically, a notification is not an I2NSF Event in the context
      of I2NSF, although they can potentially use the exact same
      information or data model.  In respect to [RFC3877], a
      Notification is a specific subset of events, because they convey
      information about "something that happens which may be of
      interest".  In consequence, Notifications may contain information
      with very low expressiveness or relevance.  Hence, additional
      post-processing functions, such as aggregation, correlation or
      simple anomaly detection, might have to be employed to satisfy a
      level of expressiveness that is required for an event-clause of an
      I2NSF Policy Rule.

   It is important to note that the consumer of a notification (the
   observer) assesses the importance of a notification and not the
   producer.  The producer can include metadata in a notification that
   supports the observer in assessing the importance (even metadata
   about severity), but the deciding entity is an I2NSF Agent.

4.3.  Unsolicited Poll and Solicited Push

   The freshness of the monitored information depends on the acquisition
   method.  Ideally, an I2NSF Agent is accessing every relevant
   information about the I2NSF Component and is emitting I2NSF Events to
   a monitoring NSF timely.  Publication of events via a pubsub/broker
   model, peer-2-peer meshes, or static defined channels are only a few
   examples on how a solicited push of I2NSF Events can be facilitated.
   The actual mechanic implemented by an I2NSF Component is out of the
   scope of this document.

   Often, corresponding management interfaces have to be queried in
   intervals or on-demand if required by an I2NSF Policy rule.  In some
   cases, a collection of information has to be conducted via login
   mechanics provided by a system entity.  Accessing records of



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   information via this kind of unsolicited polls can introduce a
   significant latency in regard to the freshness of the monitored
   information.  The actual definition of intervals implemented by an
   I2NSF Component is also out of scope of this document.

4.4.  I2NSF Monitoring Terminology for Retained Information

   Records:  Unlike information emitted via notifications and events,
      records do not require immediate attention from an analyst but may
      be useful for visibility and retroactive cyber forensic.
      Depending on the record format, there are different qualities in
      regard to structure and detail.  Records are typically stored in
      logfiles or databases on a system entity or NSF.  Records in the
      form of logfiles usually include less structures but potentially
      more detailed information in regard to changes of an system
      entity's characteristics.  In contrast, databases often use more
      strict schemas or data models, therefore enforcing a better
      structure, but inhibit storing information that do not match those
      models ('closed world assumption').  Records can be continuously
      processed by I2NSF Agents that act as I2NSF Producer and emit
      events via functions specifically tailored to a certain type of
      record.  Typically, records are information generated by NSF or
      system entity about their operational and informational data, or
      various changes in system characteristics, such as user
      activities, network/traffic status, network activity, etc.  They
      are important for debugging, auditing and security forensic.

   Counters:  A specific representation of continuous value changes of
      information elements that potentially occur in high frequency.  A
      prominent example are network interface counters, e.g.  PDU amount
      or byte amount, drop counters, error counters etc.  Counters are
      useful in debugging and visibility into operational behavior of
      the NSF.  An I2NSF Agent that observes the progression of counters
      can act as an I2NSF Producer and emit events in respect to I2NSF
      Policy Rules.

5.  Conveyance of NSF Monitoring Information

   As per the use cases of NSF monitoring data, information needs to be
   conveyed to various I2NSF Consumers based on requirements imposed by
   I2NSF Capabilities and work-flows.  There are multiple aspects to be
   considered in regard to emission of monitoring information to
   requesting parties as listed below:

   o  Pull-Push Model: A set of data can be pushed by a NSF to the
      requesting party or pulled by the requesting party from a NSF.
      Specific types of information might need both the models at the
      same time if there are multiple I2NSF Consumers with varying



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      requirements.  In general, any I2NSF Event including a high
      severity assessment is considered to be of great importance and
      should be processed as soon as possible (push-model).  Records, in
      contrast, are typically not as critical (pull-model).  The I2NSF
      Architecture does not mandate a specific scheme for each type of
      information and is therefore out of scope of this document.

   o  Pub-Sub Model: In order for an I2NSF Provider to push monitoring
      information to multiple appropriate I2NSF Consumers, a
      subscription can be maintained by both I2NSF Components.
      Discovery of available monitoring information can be supported by
      an I2NSF Controller that takes on the role of a broker and
      therefore includes I2NSF Capabilities that support registration.

   o  Export Frequency: Monitoring information can be emitted
      immediately upon generation by a NSF to requesting I2NSF Consumers
      or can be pushed periodically.  The frequency of exporting the
      data depends upon its size and timely usefulness.  It is out of
      the scope of I2NSF and left to each NSF implementation.

   o  Authentication: There may be a need for authentication between
      I2NSF Producer of monitoring information and corresponding I2NSF
      Consumer to ensure that critical information remains confidential.
      Authentication in the scope of I2NSF can also require a
      corresponding content authorization.  This may be necessary, for
      example, if a NSF emits monitoring information to I2NSF Consumer
      outside its administrative domain.  The I2NSF Architecture does
      not mandate when and how specific authentication has to be
      implemented.

   o  Data-Transfer Model: Monitoring information can be pushed by NSF
      using a connection-less model that does require a persistent
      connection or streamed over a persistent connection.  An
      appropriate model depends on the I2NSF Consumer requirements and
      the semantics of the information to be conveyed.

   o  Data Model and Interaction Model for Data in Motion: There are a
      lot of transport mechanisms such as IP, UDP, TCP.  There are also
      open source implementations for specific set of data such as
      systems counter, e.g.  IPFIX [RFC7011] or NetFlow [RFC3954].  The
      I2NSF does not mandate any specific method for a given data set,
      it is up to each implementation.

5.1.  Information Types and Acquisition Methods

   In this document most information types defined, benefit from high
   visibility with respect to value changes, e.g. alarms or records.  In
   contrast, values that change monotonically in a continuous way do not



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   benefit from this high visibility.  On the contrary, emitting each
   change would result in a useless amount of value updates.  Hence,
   values, such as counter, are best acquired in periodic intervals.

   The mechanism provided by YANG Push [I-D.ietf-netconf-yang-push] and
   YANG Subscribed Notifications
   [I-D.ietf-netconf-subscribed-notifications] address exactly these set
   of requirements.  YANG also enables semantically well-structured
   information, as well as subscriptions to datatores or event streams -
   on-change or periodically.

   In consequence, this information model is intended to support data
   models used in solicited or unsolicited event streams that
   potentially are facilitated by subscription mechanism.  A subset of
   information elements defined in the information model address this
   domain of application.

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:

   o  message_version: Indicate the version of the data format and is a
      two-digit decimal numeral starting from 01

   o  message_type: Event, Alert, Alarm, Log, Counter, etc

   o  time_stamp: Indicate the time when the message is generated

   o  vendor_name: The name of the NSF vendor

   o  NSF_name: The name (or IP) of the NSF generating the message

   o  Module_name: The module name outputting the message

   o  Severity: Indicates the level of the logs.  There are total eight
      levels, from 0 to 7.  The smaller the numeral is, the higher the
      severity is.

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.



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7.1.  System Alarm

   Characteristics:

   o  acquisition_method: subscription

   o  emission_type: on-change

   o  dampening_type: no-dampening

7.1.1.  Memory Alarm

   The following information should be included in a Memory Alarm:

   o  event_name: 'MEM_USAGE_ALARM'

   o  module_name: Indicate the NSF module responsible for generating
      this alarm

   o  usage: specifies the amount of memory used

   o  threshold: The threshold triggering the alarm

   o  severity: The severity of the alarm such as critical, high,
      medium, low

   o  message: 'The memory usage exceeded the threshold'

7.1.2.  CPU Alarm

   The following information should be included in a CPU Alarm:

   o  event_name: 'CPU_USAGE_ALARM'

   o  usage: Specifies the amount of CPU used

   o  threshold: The threshold triggering the event

   o  severity: The severity of the alarm such as critical, high,
      medium, low

   o  message: 'The CPU usage exceeded the threshold'

7.1.3.  Disk Alarm

   The following information should be included in a Disk Alarm:

   o  event_name: 'DISK_USAGE_ALARM'



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   o  usage: Specifies the amount of disk space used

   o  threshold: The threshold triggering the event

   o  severity: The severity of the alarm such as critical, high,
      medium, low

   o  message: 'The disk usage exceeded the threshold'

7.1.4.  Hardware Alarm

   The following information should be included in a Hardware Alarm:

   o  event_name: 'HW_FAILURE_ALARM'

   o  component_name: Indicate the HW component responsible for
      generating this alarm

   o  threshold: The threshold triggering the alarm

   o  severity: The severity of the alarm such as critical, high,
      medium, low

   o  message: 'The HW component has failed or degraded'

7.1.5.  Interface Alarm

   The following information should be included in a Interface Alarm:

   o  event_name: 'IFNET_STATE_ALARM'

   o  interface_Name: The name of interface

   o  interface_state: 'UP', 'DOWN', 'CONGESTED'

   o  threshold: The threshold triggering the event

   o  severity: The severity of the alarm such as critical, high,
      medium, low

   o  message: 'Current interface state'

7.2.  System Events

   Characteristics:

   o  acquisition_method: subscription




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   o  emission_type: on-change

   o  dampening_type: on_repetition

7.2.1.  Access Violation

   The following information should be included in this event:

   o  event_name: 'ACCESS_DENIED'

   o  user: Name of a user

   o  group: Group to which a user belongs

   o  login_ip_address: Login IP address of a user

   o  authentication_mode: User authentication mode. e.g., Local
      Authentication, Third-Party Server Authentication, Authentication
      Exemption, SSO Authentication

   o  message: 'access denied'

7.2.2.  Configuration Change

   The following information should be included in this event:

   o  event_name: 'CONFIG_CHANGE'

   o  user: Name of a user

   o  group: Group to which a user belongs

   o  login_ip_address: Login IP address of a user

   o  authentication_mode: User authentication mode. e.g., Local
      Authentication, Third-Party Server Authentication, Authentication
      Exemption, SSO Authentication

   o  message: 'Configuration modified'

7.3.  System Log

   Characteristics:

   o  acquisition_method: subscription

   o  emission_type: on-change




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   o  dampening_type: on_repetition

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:

   o  Administrator: Administrator that operates on the device

   o  login_ip_address: IP address used by an administrator to log in

   o  login_mode: Specifies the administrator logs in mode e.g.  root,
      user

   o  operation_type: The operation type that the administrator execute,
      e.g., login, logout, configuration, etc

   o  result: Command execution result

   o  content: Operation performed by an administrator after login.

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:

   o  system_status: The current system's running status

   o  CPU_usage: Specifies the CPU usage

   o  memory_usage: Specifies the memory usage

   o  disk_usage: Specifies the disk usage

   o  disk_left: Specifies the available disk space left

   o  session_number: Specifies total concurrent sessions

   o  process_number: Specifies total number of system processes

   o  in_traffic_rate: The total inbound traffic rate in pps

   o  out_traffic_rate: The total outbound traffic rate in pps

   o  in_traffic_speed: The total inbound traffic speed in bps



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   o  out_traffic_speed: The total outbound traffic speed in bps

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.

   o  user: Name of a user

   o  group: Group to which a user belongs

   o  login_ip_address: Login IP address of a user

   o  authentication_mode: User authentication mode. e.g., Local
      Authentication, Third-Party Server Authentication, Authentication
      Exemption, SSO Authentication

   o  access_mode: User access mode. e.g., PPP, SVN, LOCAL

   o  online_duration: Online duration

   o  lockout_duration: Lockout duration

   o  type: User activities. e.g., Successful User Login, Failed Login
      attempts, User Logout, Successful User Password Change, Failed
      User Password Change, User Lockout, User Unlocking, Unknown

   o  cause: Cause of a failed user activity

7.4.  System Counters

   Characteristics:

   o  acquisition_method: subscription or query

   o  emission_type: periodical

   o  dampening_type: none

7.4.1.  Interface counters

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

   o  interface_name: Network interface name configured in NSF




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   o  in_total_traffic_pkts: Total inbound packets

   o  out_total_traffic_pkts: Total outbound packets

   o  in_total_traffic_bytes: Total inbound bytes

   o  out_total_traffic_bytes: Total outbound bytes

   o  in_drop_traffic_pkts: Total inbound drop packets

   o  out_drop_traffic_pkts: Total outbound drop packets

   o  in_drop_traffic_bytes: Total inbound drop bytes

   o  out_drop_traffic_bytes: Total outbound drop bytes

   o  in_traffic_ave_rate: Inbound traffic average rate in pps

   o  in_traffic_peak_rate: Inbound traffic peak rate in pps

   o  in_traffic_ave_speed: Inbound traffic average speed in bps

   o  in_traffic_peak_speed: Inbound traffic peak speed in bps

   o  out_traffic_ave_rate: Outbound traffic average rate in pps

   o  out_traffic_peak_rate: Outbound traffic peak rate in pps

   o  out_traffic_ave_speed: Outbound traffic average speed in bps

   o  out_traffic_peak_speed: Outbound traffic peak speed in bps.

7.5.  NSF Events

   Characteristics:

   o  acquisition_method: subscription

   o  emission_type: on-change

   o  dampening_type: none

7.5.1.  DDoS Event

   The following information should be included in a DDoS Event:

   o  event_name: 'SEC_EVENT_DDoS'




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   o  sub_attack_type: Any one of Syn flood, ACK flood, SYN-ACK flood,
      FIN/RST flood, TCP Connection flood, UDP flood, Icmp flood, HTTPS
      flood, HTTP flood, DNS query flood, DNS reply flood, SIP flood,
      and etc.

   o  dst_ip: The IP address of a victum under attack

   o  dst_port: The port numbers that the attrack traffic aims at.

   o  start_time: The time stamp indicating when the attack started

   o  end_time: The time stamp indicating when the attack ended.  If the
      attack is still undergoing when sending out the alarm, this field
      can be empty.

   o  attack_rate: The PPS of attack traffic

   o  attack_speed: the bps of attack traffic

   o  rule_id: The ID of the rule being triggered

   o  rule_name: The name of the rule being triggered

   o  profile: Security profile that traffic matches.

7.5.2.  Session Table Event

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

   o  event_name: 'SESSION_USAGE_HIGH'

   o  current: The number of concurrent sessions

   o  max: The maximum number of sessions that the session table can
      support

   o  threshold: The threshold triggering the event

   o  message: 'The number of session table exceeded the threshold'

7.5.3.  Virus Event

   The following information should be included in a Virus Event:

   o  event_Name: 'SEC_EVENT_VIRUS'





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   o  virus_type: Type of the virus, e.g., trojan, worm, macro Virus
      type

   o  virus_name

   o  dst_ip: The destination IP address of the packet where the virus
      is found

   o  src_ip: The source IP address of the packet where the virus is
      found

   o  src_port: The source port of the packet where the virus is found

   o  dst_port: The destination port of the packet where the virus is
      found

   o  src_zone: The source security zone of the packet where the virus
      is found

   o  dst_zone: The destination security zone of the packet where the
      virus is found

   o  file_type: The type of the file where the virus is hided within

   o  file_name: The name of the file where the virus is hided within

   o  virus_info: The brief introduction of virus

   o  raw_info: The information describing the packet triggering the
      event.

   o  rule_id: The ID of the rule being triggered

   o  rule_name: The name of the rule being triggered

   o  profile: Security profile that traffic matches.

7.5.4.  Intrusion Event

   The following information should be included in a Intrustion Event:

   o  event_name: The name of event: 'SEC_EVENT_Intrusion'

   o  sub_attack_type: Attack type, e.g., brutal force, buffer overflow

   o  src_ip: The source IP address of the packet

   o  dst_ip: The destination IP address of the packet



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   o  src_port:The source port number of the packet

   o  dst_port: The destination port number of the packet

   o  src_zone: The source security zone of the packet

   o  dst_zone: The destination security zone of the packet

   o  protocol: The employed transport layer protocol, e.g.,TCP, UDP

   o  app: The employed application layer protocol, e.g.,HTTP, FTP

   o  rule_id: The ID of the rule being triggered

   o  rule_name: The name of the rule being triggered

   o  profile: Security profile that traffic matches

   o  intrusion_info: Simple description of intrusion

   o  raw_info: The information describing the packet triggering the
      event.

7.5.5.  Botnet Event

   The following information should be included in a Botnet Event:

   o  event_name: the name of event: 'SEC_EVENT_Botnet'

   o  botnet_name: The name of the detected botnet

   o  src_ip: The source IP address of the packet

   o  dst_ip: The destination IP address of the packet

   o  src_port: The source port number of the packet

   o  dst_port: The destination port number of the packet

   o  src_zone: The source security zone of the packet

   o  dst_zone: The destination security zone of the packet

   o  protocol: The employed transport layer protocol, e.g.,TCP, UDP

   o  app: The employed application layer protocol, e.g.,HTTP, FTP

   o  role: The role of the communicating parties within the botnet:



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      1.  the packet from zombie host to the attacker

      2.  The packet from the attacker to the zombie host

      3.  The packet from the IRC/WEB server to the zombie host

      4.  The packet from the zombie host to the IRC/WEB server

      5.  The packet from the attacker to the IRC/WEB server

      6.  The packet from the IRC/WEB server to the attacker

      7.  The packet from the zombie host to the victim

   o  botnet_info: Simple description of Botnet

   o  rule_id: The ID of the rule being triggered

   o  rule_name: The name of the rule being triggered

   o  profile: Security profile that traffic matches

   o  raw_info: The information describing the packet triggering the
      event.

7.5.6.  Web Attack Event

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

   o  event_name: the name of event: 'SEC_EVENT_WebAttack'

   o  sub_attack_type: Concret web attack type, e.g., sql injection,
      command injection, XSS, CSRF

   o  src_ip: The source IP address of the packet

   o  dst_ip: The destination IP address of the packet

   o  src_port: The source port number of the packet

   o  dst_port: The destination port number of the packet

   o  src_zone: The source security zone of the packet

   o  dst_zone: The destination security zone of the packet

   o  req_method: The method of requirement.  For instance, 'PUT' or
      'GET' in HTTP



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   o  req_url: Requested URL

   o  url_category: Matched URL category

   o  filtering_type: URL filtering type, e.g., Blacklist, Whitelist,
      User-Defined, Predefined, Malicious Category, Unknown

   o  rule_id: The ID of the rule being triggered

   o  rule_name: The name of the rule being triggered

   o  profile: Security profile that traffic matches.

7.6.  NSF Logs

   Characteristics:

   o  acquisition_method: subscription

   o  emission_type: on-change

   o  dampening_type: on_repetition

7.6.1.  DDoS Logs

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

   o  attack_type: DDoS

   o  attack_ave_rate: The average pps of the attack traffic within the
      recorded time

   o  attack_ave_speed: The average bps of the attack traffic within the
      recorded time

   o  attack_pkt_num: The number attack packets within the recorded time

   o  attack_src_ip: The source IP addresses of attack traffics.  If
      there are a large amount of IP addresses, then pick a certain
      number of resources according to different rules.

   o  action: Actions against DDoS attacks, e.g., Allow, Alert, Block,
      Discard, Declare, Block-ip, Block-service.







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7.6.2.  Virus Logs

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

   o  attack_type: Virus

   o  protocol: The transport layer protocol

   o  app: The name of the application layer protocol

   o  times: The time of detecting the virus

   o  action: The actions dealing with the virus, e.g., alert, block

   o  os: The OS that the virus will affect, e.g., all, android, ios,
      unix, windows

7.6.3.  Intrusion Logs

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

   o  attack_type: Intrusion

   o  times: The times of intrusions happened in the recorded time

   o  os: The OS that the intrusion will affect, e.g., all, android,
      ios, unix, windows

   o  action: The actions dealing with the intrusions, e.g., e.g.,
      Allow, Alert, Block, Discard, Declare, Block-ip, Block-service

   o  attack_rate: NUM the pps of attack traffic

   o  attack_speed: NUM the bps of attack traffic

7.6.4.  Botnet Logs

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

   o  attack_type: Botnet

   o  botnet_pkt_num:The number of the packets sent to or from the
      detected botnet





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   o  action: The actions dealing with the detected packets, e.g.,
      Allow, Alert, Block, Discard, Declare, Block-ip, Block-service,
      etc

   o  os: The OS that the attack aiming at, e.g., all, android, ios,
      unix, windows, etc.

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.

   o  type: DPI action types. e.g., File Blocking, Data Filtering,
      Application Behavior Control

   o  file_name: The file name

   o  file_type: The file type

   o  src_zone: Source security zone of traffic

   o  dst_zone: Destination security zone of traffic

   o  src_region: Source region of the traffic

   o  dst_region: Destination region of the traffic

   o  src_ip: Source IP address of traffic

   o  src_user: User who generates traffic

   o  dst_ip: Destination IP address of traffic

   o  src_port: Source port of traffic

   o  dst_port: Destination port of traffic

   o  protocol: Protocol type of traffic

   o  app: Application type of traffic

   o  policy_id: Security policy id that traffic matches

   o  policy_name: Security policy name that traffic matches





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   o  action: Action defined in the file blocking rule, data filtering
      rule, or application behavior control rule that traffic matches.

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:

   o  victim_ip: IP address of the victim host which has vulnerabilities

   o  vulnerability_id: The vulnerability id

   o  vulnerability_level: The vulnerability level. e.g., high, middle,
      low

   o  OS: The operating system of the victim host

   o  service: The service which has vulnerabillity in the victim host

   o  protocol: The protocol type. e.g., TCP, UDP

   o  port: The port number

   o  vulnerability_info: The information about the vulnerability

   o  fix_suggestion: The fix suggestion to the vulnerability.

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:

   o  attack_type: Web Attack

   o  rsp_code: Response code

   o  req_clientapp: The client application

   o  req_cookies: Cookies

   o  req_host: The domain name of the requested host

   o  raw_info: The information describing the packet triggering the
      event.






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7.7.  NSF Counters

   Characteristics:

   o  acquisition_method: subscription or query

   o  emission_type: periodical

   o  dampening_type: none

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.

   o  src_zone: Source security zone of traffic

   o  dst_zone: Destination security zone of traffic

   o  src_region: Source region of the traffic

   o  dst_region: Destination region of the traffic

   o  src_ip: Source IP address of traffic

   o  src_user: User who generates traffic

   o  dst_ip: Destination IP address of traffic

   o  src_port: Source port of traffic

   o  dst_port: Destination port of traffic

   o  protocol: Protocol type of traffic

   o  app: Application type of traffic

   o  policy_id: Security policy id that traffic matches

   o  policy_name: Security policy name that traffic matches

   o  in_interface: Inbound interface of traffic

   o  out_interface: Outbound interface of traffic

   o  total_traffic: Total traffic volume




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   o  in_traffic_ave_rate: Inbound traffic average rate in pps

   o  in_traffic_peak_rate: Inbound traffic peak rate in pps

   o  in_traffic_ave_speed: Inbound traffic average speed in bps

   o  in_traffic_peak_speed: Inbound traffic peak speed in bps

   o  out_traffic_ave_rate: Outbound traffic average rate in pps

   o  out_traffic_peak_rate: Outbound traffic peak rate in pps

   o  out_traffic_ave_speed: Outbound traffic average speed in bps

   o  out_traffic_peak_speed: Outbound traffic peak speed in bps.

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.

   o  src_zone: Source security zone of traffic

   o  dst_zone: Destination security zone of traffic

   o  src_region: Source region of the traffic

   o  dst_region: Destination region of the traffic

   o  src_ip: Source IP address of traffic

   o  src_user: User who generates traffic

   o  dst_ip: Destination IP address of traffic

   o  src_port: Source port of traffic

   o  dst_port: Destination port of traffic

   o  protocol: Protocol type of traffic

   o  app: Application type of traffic

   o  policy_id: Security policy id that traffic matches

   o  policy_name: Security policy name that traffic matches




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   o  hit_times: The hit times that the security policy matches the
      specified traffic.

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.  References

10.1.  Normative References

   [I-D.ietf-core-yang-cbor]
              Veillette, M., Pelov, A., Somaraju, A., Turner, R., and A.
              Minaburo, "CBOR Encoding of Data Modeled with YANG",
              draft-ietf-core-yang-cbor-07 (work in progress), September
              2018.

   [I-D.ietf-netconf-subscribed-notifications]
              Voit, E., Clemm, A., Prieto, A., Nilsen-Nygaard, E., and
              A. Tripathy, "Customized Subscriptions to a Publisher's
              Event Streams", draft-ietf-netconf-subscribed-
              notifications-17 (work in progress), September 2018.








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   [I-D.ietf-netconf-yang-push]
              Clemm, A., Voit, E., Prieto, A., Tripathy, A., Nilsen-
              Nygaard, E., Bierman, A., and B. Lengyel, "Subscription to
              YANG Datastores", draft-ietf-netconf-yang-push-20 (work in
              progress), October 2018.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3877]  Chisholm, S. and D. Romascanu, "Alarm Management
              Information Base (MIB)", RFC 3877, DOI 10.17487/RFC3877,
              September 2004, <https://www.rfc-editor.org/info/rfc3877>.

   [RFC4765]  Debar, H., Curry, D., and B. Feinstein, "The Intrusion
              Detection Message Exchange Format (IDMEF)", RFC 4765,
              DOI 10.17487/RFC4765, March 2007,
              <https://www.rfc-editor.org/info/rfc4765>.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
              FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
              <https://www.rfc-editor.org/info/rfc4949>.

   [RFC5424]  Gerhards, R., "The Syslog Protocol", RFC 5424,
              DOI 10.17487/RFC5424, March 2009,
              <https://www.rfc-editor.org/info/rfc5424>.

   [RFC6587]  Gerhards, R. and C. Lonvick, "Transmission of Syslog
              Messages over TCP", RFC 6587, DOI 10.17487/RFC6587, April
              2012, <https://www.rfc-editor.org/info/rfc6587>.

   [RFC7011]  Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
              "Specification of the IP Flow Information Export (IPFIX)
              Protocol for the Exchange of Flow Information", STD 77,
              RFC 7011, DOI 10.17487/RFC7011, September 2013,
              <https://www.rfc-editor.org/info/rfc7011>.

10.2.  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", draft-ietf-i2nsf-framework-10 (work in
              progress), November 2017.






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   [I-D.ietf-i2nsf-terminology]
              Hares, S., Strassner, J., Lopez, D., Xia, L., and H.
              Birkholz, "Interface to Network Security Functions (I2NSF)
              Terminology", draft-ietf-i2nsf-terminology-06 (work in
              progress), July 2018.

   [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",
              draft-xia-i2nsf-capability-interface-im-06 (work in
              progress), July 2016.

   [I-D.xibassnez-i2nsf-capability]
              Xia, L., Strassner, J., Basile, C., and D. Lopez,
              "Information Model of NSFs Capabilities", draft-xibassnez-
              i2nsf-capability-02 (work in progress), July 2017.

   [RFC3954]  Claise, B., Ed., "Cisco Systems NetFlow Services Export
              Version 9", RFC 3954, DOI 10.17487/RFC3954, October 2004,
              <https://www.rfc-editor.org/info/rfc3954>.

Acknowledgements

Authors' Addresses

   Liang Xia
   Huawei

   Email: frank.xialiang@huawei.com


   Dacheng Zhang
   Huawei

   Email: dacheng.zhang@huawei.com


   Yi Wu
   Aliababa Group

   Email: anren.wy@alibaba-inc.com


   Rakesh Kumar
   Juniper Networks

   Email: rkkumar@juniper.net



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   Anil Lohiya
   Juniper Networks

   Email: alohiya@juniper.net


   Henk Birkholz
   Fraunhofer SIT

   Email: henk.birkholz@sit.fraunhofer.de









































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