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Versions: 00 01 02 03 04 05                                             
Network Working Group                                           J. Jeong
Internet-Draft                                                    H. Kim
Intended status: Standards Track                 Sungkyunkwan University
Expires: April 11, 2016                                          J. Park
                                                                    ETRI
                                                         October 9, 2015


 Software-Defined Networking Based Security Services using Interface to
                       Network Security Functions
               draft-jeong-i2nsf-sdn-security-services-03

Abstract

   This document describes a framework, objectives, requirements, and
   use cases for security services based on Software-Defined Networking
   (SDN) using a common Interface to Network Security Functions (I2NSF).
   It first proposes the framework of SDN-based security services in the
   I2NSF framework.  It then explains two use cases, such as centralized
   firewall system and centralized DDoS-attack mitigation system.

Status of This Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   Drafts.

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   This Internet-Draft will expire on April 11, 2016.

Copyright Notice

   Copyright (c) 2015 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
   (http://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.  Requirements Language  . . . . . . . . . . . . . . . . . . . .  4
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   5.  Objectives . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  7
   7.  Use Cases  . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     7.1.  Centralized Firewall System  . . . . . . . . . . . . . . .  8
     7.2.  Centralized DDoS-attack Mitigation System  . . . . . . . .  9
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 11
     10.2. Informative References . . . . . . . . . . . . . . . . . . 11

























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1.  Introduction

   Software-Defined Networking (SDN) is a set of techniques that enables
   users to directly program, orchestrate, control and manage network
   resources through software (e.g., SDN applications).  It relocates
   the control of network resources to a dedicated network element,
   namely SDN controller.  The SDN controller uses interfaces to
   arbitrate the control of network resources in a logically centralized
   manner.  It also manages and configures the distributed network
   resources, and provides the abstracted view of the network resources
   to the SDN applications.  The SDN applications can customize and
   automate the operations (including management) of the abstracted
   network resources in a programmable manner via the interfaces
   [RFC7149][ITU-T.Y.3300][ONF-SDN-Architecture][ONF-OpenFlow].

   Due to the increase of sophisticated network attacks, the legacy
   security services become difficult to cope with such network attacks
   in an autonomous manner.  SDN has been introduced to make networks
   more controllable and manageable, and this SDN technology will be
   promising to autonomously deal with such network attacks in a prompt
   manner.

   This document describes a framework, objectives and requirements to
   support the protection of network resources through SDN-based
   security services using a common interface to Network Security
   Functions (NSF) [i2nsf-framework].  It uses an interface to NSF
   (I2NSF) for such SDN-based security services that are performed in
   virtual machines through network functions virtualization [ETSI-NFV].

   This document addresses the challenges of the exisiting systems for
   security services.  As feasible solutions to handle these challenges,
   this document proposes two use cases of the security services, such
   as centralized firewall system and centralized DDoS-attack mitigation
   system.

   For the centralized firewall system, this document raises limitations
   in legacy firewalls in terms of flexibility and administration costs.
   Since in many cases, access control management for firewall is
   manually performed, it is difficult to add the access control policy
   rules corresponding to new network attacks in a prompt and autonomous
   manner.  Thus, this situation requires expensive administration
   costs.  This document introduces a use case of SDN-based firewall
   system to overcome these limitations.

   For the centralized DDoS-attack mitigation system, this document
   raises limitations in legacy DDoS-attack mitigation techniques in
   terms of flexibility and administration costs.  Since in many cases,
   network configuration for the mitigation is manually performed, it is



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   difficult to dynamically configure network devices to limit and
   control suspicious network traffic for DDoS attacks.  This document
   introduces a use case of SDN-based DDoS-attack mitigation system to
   provide an autonomous and prompt configuration for suspicious network
   traffic.

2.  Requirements Language

   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 RFC 2119 [RFC2119].

3.  Terminology

   This document uses the terminology described in [RFC7149],
   [ITU-T.Y.3300], [ONF-SDN-Architecture], [ONF-OpenFlow],
   [ITU-T.X.1252], and [ITU-T.X.800].  In addition, the following terms
   are defined below:

   o  Software-Defined Networking: A set of techniques that enables to
      directly program, orchestrate, control, and manage network
      resources, which facilitates the design, delivery and operation of
      network services in a dynamic and scalable manner [ITU-T.Y.3300].

   o  Access Control: A procedure used to determine if an entity should
      be granted access to resources, facilities, services, or
      information based on pre-established rules and specific rights or
      authority associated with the requesting party [ITU-T.X.1252].

   o  Access Control Policy: The set of rules that define the conditions
      under which access may take place [ITU-T.X.800].

   o  Access Control Policy Rules: Security policy rules concerning the
      provision of the access control service [ITU-T.X.800].

   o  Network Resources: Network devices that can perform packet
      forwarding in a network system.  The network resources include
      network switch, router, gateway, WiFi access points, and similar
      devices.

   o  Firewall: A firewall that is a device or service at the junction
      of two network segments that inspects every packet that attempts
      to cross the boundary.  It also rejects any packet that does not
      satisfy certain criteria for disallowed port numbers or IP
      addresses.

   o  Centralized Firewall System: A centralized firewall that can
      establish and distribute access control policy rules into network



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      resources for efficient firewall management.  These rules can be
      managed dynamically by a centralized server for firewall.  SDN can
      work as a network-based firewall system through a standard
      interface between firewall applications and network resources.

   o  Centralized DDoS-attack Mitigation System: A centralized mitigator
      that can establish and distribute access control policy rules into
      network resources for efficient DDoS-attack mitigation.  These
      rules can be managed dynamically by a centralized server for DDoS-
      attack mitigation.  SDN can work as a network-based mitigation
      system through a standard interface between DDoS-attack mitigation
      applications and network resources.

4.  Overview

   This section describes the referenced architecture to support SDN-
   based security services, such as centralized firewall system and
   centralized DDoS-attack mitigation system.  Also, it describes a
   framework for SDN-based security services using I2NSF.

   |
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | |              Security Functions             |
   | |  (e.g., firewall, DDoS-attack mitigation,   | Application
   | |        web filter, deep packet inspection)  | Layer
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |------------------------------------------------------------
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (Application-
   | |              Application Support            |  Control Interface)
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | |                 Orchestration               | SDN Controller
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Layer
   | |                  Abstraction                |
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |-------------------------------------------------------------
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (Resource-
   | |                Control Support              |  Control Interface)
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | |         Data Transport and Processing       | Resource Layer
   | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |

     Figure 1: High-level Architecture for SDN-based Security Services

   As shown in Figure 1, security functions as security services (e.g.,
   firewall, DDoS-attack mitigation, web filter, deep packet inspection)
   run on the top of SDN controller [ITU-T.Y.3300]
   [ONF-SDN-Architecture].  When an administrator enforces security



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   policies for such security services through an application interface,
   SDN controller generates the corresponding access control policy
   rules to meet such security policies in an autonomous and prompt
   manner.  According to the generated access control policy rules, the
   network resources such as switches take an action to mitigate network
   attacks, for example, dropping packets with suspicious patterns.

       +------------+
       |Client/AppGW|
       +------------+
              |
              | Service Layer Interface
              |
    +-------------------+                           +-------------+
    |Security Controller|<------------------------->|Vendor System|
    +-------------------+  Vendor Facing Interface  +-------------+
              |
              | Capability Layer Interface
              |
    +-------------------+ +-------------------+    +-------------------+
    |Security Function 1|-|Security Function 2|....|Security Function n|
    +-------------------+ +-------------------+    +-------------------+
              |
              | SDN Northbound Interface
              |
     +-----------------+
     |Switch Controller|
     +-----------------+
              |
              | SDN Southbound Interface
              |
         +--------+ +--------+      +--------+
         |Switch 1|-|Switch 2|......|Switch m|
         +--------+ +--------+      +--------+

     Figure 2: A Framework for SDN-based Security Services using I2NSF

   Figure 2 shows a framework to support SDN-based security services
   using I2NSF [i2nsf-framework].  As shown in Figure 2, client and
   application gateway (AppGW) can use security services by delivering
   their high-level security policies to security controller via service
   layer interface.  Security controller asks security function(s)
   function-level security services via capability layer interface.  The
   security functions run on top of virtual machines through NFV
   [ETSI-NFV].  Securiy functions asks switch controller to perform
   their required security services on switches under the supervision of
   switch controller.




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   Capability layer interface between security controller and security
   functions can be implemented by Network Configuration Protocol
   (NETCONF) [RFC6241] with a data modeling language called YANG
   [RFC6020] that describes function-level security services.

5.  Objectives

   o  Prompt reaction to new network attacks: SDN-based security
      services allow private networks to defend themselves against new
      sophisticated network attacks.

   o  Automatic defense from network attacks: SDN-based security
      services identify the category of network attack (e.g., malware
      and DDoS attacks) and take counteraction for the defense without
      the intervention of network administrators.

   o  Network-load-aware resource allocation: SDN-based security
      services measure the overhead of resources for security services
      and dynamically select resources considering load balance for the
      maximum network performance.

6.  Requirements

   SDN-based security services provide dynamic and flexible network
   resource management to mitigate network attacks, such as malware and
   DDoS attacks.  In order to support this capability, the requirements
   for SDN-based security services are described as follows:

   o  SDN-based security services are required to support the
      programmability of network resources to mitigate network attacks.

   o  SDN-based security services are required to support the
      orchestration of network resources and SDN applications to
      mitigate network attacks.

   o  SDN-based security services are required to provide an application
      interface allowing the management of access control policies in an
      autonomous and prompt manner.

   o  SDN-based security services are required to provide a resource-
      control interface for the control of network resources to mitigate
      network attacks.

   o  SDN-based security services are required to provide the logically
      centralized control of network resources to mitigate network
      attacks.





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7.  Use Cases

   This section introduces two use cases for security services based on
   SDN: (i) centralized firewall system and (ii) centralized DDoS-attack
   mitigation system.

7.1.  Centralized Firewall System

   For the centralized firewall system, a centralized network firewall
   can manage each network resource and firewall rules can be managed
   flexibly by a centralized server for firewall (called Firewall).  The
   centralized network firewall controls each switch for the network
   resource management and the firewall rules can be added or deleted
   dynamically.

   The procedure of firewall operations in the centralized firewall
   system is as follows:

   1.  Switch forwards an unknown flow's packet to SDN Controller.

   2.  SDN Controller forwards the unknown flow's packet to an
       appropriate security service application, such as Firewall.

   3.  Firewall analyzes the headers and contents of the packet.

   4.  If Firewall regards the packet as a malware's packet with a
       suspicious pattern, it reports the malware's packet to SDN
       Controller.

   5.  SDN Controller installs new rules (e.g., drop packets with the
       suspicious pattern) into switches.

   6.  The malware's packets are dropped by switches.

   For the above centralized firewall system, the existing SDN protocols
   can be used through standard interfaces between the firewall
   application and switches [RFC7149][ITU-T.Y.3300]
   [ONF-SDN-Architecture][ONF-OpenFlow].

   Legacy firewalls have some challenges such as the expensive cost,
   performance, management of access control, establishment of policy,
   and packet-based access mechanism.  The proposed framework can
   resolve these challenges through the above centralized firewall
   system based on SDN as follows.

   o  Cost: The cost of adding firewalls to network resources such as
      routers, gateways, and switches is substantial due to the reason
      that we need to add firewall on each network resource.  To solve



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      this, each network resource can be managed centrally such that a
      single firewall is manipulated by a centralized server.

   o  Performance: The performance of firewalls is often slower than the
      link speed of network interfaces.  Every network resource for
      firewall needs to check firewall rules according to network
      conditions.  Firewalls can be adaptively deployed among network
      switches, depending on network conditions in the framework.

   o  The management of access control: Since there may be hundreds of
      network resources in an administered network, the dynamic
      management of access control for security services like firewall
      is a challenge.  In the framework, firewall rules can be
      dynamically added for new malware.

   o  The establishment of policy: Policy should be established for each
      network resource.  However, it is difficult to describe what flows
      are permitted or denied for firewall within a specific
      organization network under management.  Thus, a centralized view
      is helpful to determine security policies for such a network.

   o  Packet-based access mechanism: Packet-based access mechanism is
      not enough for firewall in practice since the basic unit of access
      control is usually users or applications.  Therefore, application
      level rules can be defined and added to the firewall system
      through the centralized server.

7.2.  Centralized DDoS-attack Mitigation System

   For the centralized DDoS-attack mitigation system, a centralized
   DDoS-attack mitigation can manage each network resource and
   manipulate rules to each switch through a centralized server for
   DDoS-attack mitigation (called DDoS-attack Mitigator).  The
   centralized DDoS-attack mitigation system defends servers against
   DDoS attacks outside private network, that is, from public network.

   Servers are categorized into stateless servers (e.g., DNS servers)
   and stateful servers (e.g., web servers).  For DDoS-attack
   mitigation, traffic flows in switches are dynamically configured by
   traffic flow forwarding path management according to the category of
   servers [AVANT-GUARD].  Such a managenent should consider the load
   balance among the switches for the defense against DDoS attacks.

   The procedure of DDoS-attack mitigation operations in the centralized
   DDoS-attack mitigation system is as follows:

   1.  Switch periodically reports an inter-arrival pattern of a flow's
       packets to SDN Controller.



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   2.  SDN Controller forwards the flow's inter-arrival pattern to an
       appropriate security service application, such as DDoS-attack
       Mitigator.

   3.  DDoS-attack Mitigator analyzes the reported pattern for the flow.

   4.  If DDoS-attack Mitigator regards the pattern as a DDoS attack, it
       computes a packet dropping probability corresponding to
       suspiciousness level and reports this DDoS-attack flow to SDN
       Controller.

   5.  SDN Controller installs new rules into switches (e.g., forward
       packets with the suspicious inter-arrival pattern with a dropping
       probability).

   6.  The suspicious flow's packets are randomly dropped by switches
       with the dropping probability.

   For the above centralized DDoS-attack mitigation system, the existing
   SDN protocols can be used through standard interfaces between the
   DDoS-attack mitigator application and switches [RFC7149]
   [ITU-T.Y.3300][ONF-SDN-Architecture][ONF-OpenFlow].

   The centralized DDoS-attack mitigation system has challenges similar
   to the centralized firewall system.  The proposed framework can
   resolve these challenges through the above centralized DDoS-attack
   mitigation system based on SDN as follows.

   o  Cost: The cost of adding DDoS-attack mitigators to network
      resources such as routers, gateways, and switches is substantial
      due to the reason that we need to add DDoS-attack mitigator on
      each network resource.  To solve this, each network resource can
      be managed centrally such that a single DDoS-attack mitigator is
      manipulated by a centralized server.

   o  Performance: The performance of DDoS-attack mitigators is often
      slower than the link speed of network interfaces.  The checking of
      DDoS attacks may reduce the performance of the network interfaces.
      DDoS-attack mitigators can be adaptively deployed among network
      switches, depending on network conditions in the framework.

   o  The management of network resources: Since there may be hundreds
      of network resources in an administered network, the dynamic
      management of network resources for performance (e.g., load
      balancing) is a challenge for DDoS-attack mitigation.  In the
      framework, as dynamic network resource management, traffic flow
      forwarding path management can handle the load balancing of
      network switches [AVANT-GUARD].  With this management, the current



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      and near-future workload can be spread among the network switches
      for DDoS-attack mitigation.  In addition, DDoS-attack mitigation
      rules can be dynamically added for new DDoS attacks.

   o  The establishment of policy: Policy should be established for each
      network resource.  However, it is difficult to describe what flows
      are permitted or denied for new DDoS-attacks (e.g., DNS reflection
      attack) within a specific organization network under management.
      Thus, a centralized view is helpful to determine security policies
      for such a network.

8.  Security Considerations

   This document shares all the security issues of SDN that are
   specified in the "Security Considerations" section of [ITU-T.Y.3300].

9.  Acknowledgements

   This work was partly supported by the ICT R&D program of MSIP/IITP
   [10041244, SmartTV 2.0 Software Platform] and ETRI.

   This document has greatly benefited from inputs by Jinyong Kim, Mahdi
   Daghmehchir-Firoozjaei, and Geumhwan Cho.

10.  References

10.1.  Normative References

   [RFC2119]               Bradner, S., "Key words for use in RFCs to
                           Indicate Requirement Levels", BCP 14,
                           RFC 2119, March 1997.

   [i2nsf-framework]       Lopez, E., Lopez, D., Dunbar, L., Zhuang, X.,
                           Parrott, J., Krishnan, R., and S. Durbha,
                           "Framework for Interface to Network Security
                           Functions", draft-merged-i2nsf-framework-02 ,
                           June 2015.

10.2.  Informative References

   [RFC7149]               Boucadair, M. and C. Jacquenet, "Software-
                           Defined Networking: A Perspective from within
                           a Service Provider Environment", RFC 7149,
                           March 2014.

   [RFC6241]               Enns, R., Bjorklund, M., Schoenwaelder, J.,
                           and A. Bierman, "Network Configuration
                           Protocol (NETCONF)", RFC 6241, June 2011.



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   [RFC6020]               Bjorklund, M., "YANG - A Data Modeling
                           Language for the Network Configuration
                           Protocol (NETCONF)", RFC 6020, October 2010.

   [ITU-T.Y.3300]          Recommendation ITU-T Y.3300, "Framework of
                           Software-Defined Networking", June 2014.

   [ONF-SDN-Architecture]  ONF, "SDN Architecture", June 2014.

   [ONF-OpenFlow]          ONF, "OpenFlow Switch Specification (Version
                           1.4.0)", October 2013.

   [ITU-T.X.1252]          Recommendation ITU-T X.1252, "Baseline
                           Identity Management Terms and Definitions",
                           April 2010.

   [ITU-T.X.800]           Recommendation ITU-T X.800, "Security
                           Architecture for Open Systems Interconnection
                           for  CCITT Applications", March 1991.

   [AVANT-GUARD]           Shin, S., Yegneswaran, V., Porras, P., and G.
                           Gu, "AVANT-GUARD: Scalable and Vigilant
                           Switch Flow Management in Software-Defined
                           Networks", ACM CCS, November 2013.

   [ETSI-NFV]              ETSI GS NFV 002 V1.1.1, "Network Functions
                           Virtualisation (NFV); Architectural
                           Framework", October 2013.

Authors' Addresses

   Jaehoon Paul Jeong
   Department of Software
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon, Gyeonggi-Do  440-746
   Republic of Korea

   Phone: +82 31 299 4957
   Fax:   +82 31 290 7996
   EMail: pauljeong@skku.edu
   URI:   http://cpslab.skku.edu/people-jaehoon-jeong.php









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   Hyoungshick Kim
   Department of Software
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon, Gyeonggi-Do  440-746
   Republic of Korea

   Phone: +82 31 299 4324
   Fax:   +82 31 290 7996
   EMail: hyoung@skku.edu
   URI:   http://seclab.skku.edu/people/hyoungshick-kim/


   Jung-Soo Park
   Electronics and Telecommunications Research Institute
   218 Gajeong-Ro, Yuseong-Gu
   Daejeon,   305-700
   Republic of Korea

   Phone: +82 42 860 6514
   EMail: pjs@etri.re.kr






























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