Applicability of Interfaces to Network Security Functions to Network-Based Security Services
draft-ietf-i2nsf-applicability-04
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| Authors | Jaehoon Paul Jeong , Sangwon Hyun , Tae-Jin Ahn , Susan Hares , Diego Lopez | ||
| Last updated | 2018-07-17 | ||
| Replaces | draft-jeong-i2nsf-applicability | ||
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draft-ietf-i2nsf-applicability-04
I2NSF Working Group J. Jeong
Internet-Draft Sungkyunkwan University
Intended status: Informational S. Hyun
Expires: January 18, 2019 Chosun University
T. Ahn
Korea Telecom
S. Hares
Huawei
D. Lopez
Telefonica I+D
July 17, 2018
Applicability of Interfaces to Network Security Functions to Network-
Based Security Services
draft-ietf-i2nsf-applicability-04
Abstract
This document describes the applicability of Interface to Network
Security Functions (I2NSF) to network-based security services in
Network Functions Virtualization (NFV) environments, such as
firewall, deep packet inspection, or attack mitigation engines.
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 January 18, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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(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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. I2NSF Framework . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Time-dependent Web Access Control Service . . . . . . . . 5
4. I2NSF Framework with SFC . . . . . . . . . . . . . . . . . . 7
5. I2NSF Framework with SDN . . . . . . . . . . . . . . . . . . 9
5.1. Firewall: Centralized Firewall System . . . . . . . . . . 11
5.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security
System . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3. Attack Mitigation: Centralized DDoS-attack Mitigation
System . . . . . . . . . . . . . . . . . . . . . . . . . 14
6. I2NSF Framework with NFV . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
10. Informative References . . . . . . . . . . . . . . . . . . . 20
Appendix A. Changes from draft-ietf-i2nsf-applicability-03 . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
Interface to Network Security Functions (I2NSF) defined a framework
and interfaces for interacting with Network Security Functions
(NSFs). The I2NSF framework allows heterogeneous NSFs developed by
different security solution vendors to be used in the NFV environment
by utilizing the capabilities of such products and the virtualization
of security functions in the NFV platform. In the I2NSF framework,
each NSF initially registers the profile of its own capabilities into
the system in order for themselves to be available in the system. In
addition, the Security Controller registers itself to the I2NSF user
so that the user can request security services to the Security
Controller.
This document describes the applicability of I2NSF framework to
network-based security services with a use case of time-dependent web
access control. This document also describes integrating I2NSF
framework with Software-Defined Networking (SDN) technology for
efficient security services and use cases, such as firewall
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[opsawg-firewalls], Deep Packet Inspection (DPI), and Distributed
Denial of Service (DDoS) attack mitigation. We implemented the I2NSF
framework based on SDN for these use cases, and the implementation
successfully verified the effectiveness of the I2NSF framework.
2. Terminology
This document uses the terminology described in [RFC7149],
[ITU-T.Y.3300], [ONF-OpenFlow], [ONF-SDN-Architecture],
[ITU-T.X.1252], [ITU-T.X.800], [RFC8329], [i2nsf-terminology],
[consumer-facing-inf-im], [consumer-facing-inf-dm],
[i2nsf-nsf-cap-im], [nsf-facing-inf-dm], [registration-inf-im],
[registration-inf-dm], and [nsf-triggered-steering]. In addition,
the following terms are defined below:
o Software-Defined Networking (SDN): 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 Firewall: A service function 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, for example, disallowed port numbers or IP
addresses.
o Centralized Firewall System: A centralized firewall that can
establish and distribute policy rules into network 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 an SDN switch and a firewall function as a vitual network
function (VNF).
o Centralized VoIP Security System: A centralized security system
that handles the security functions required for VoIP and VoLTE
services. SDN can work as a network-based security system through
a standard interface between an SDN switch and a VoIP/VoLTE
security function as a VNF.
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. The SDN controller and switches can
cooperatively work as a network-based firewall system through a
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standard interface between an SDN switch and a firewall function
as a VNF running in the SDN controller.
3. I2NSF Framework
This section describes an I2NSF framework and its use case. Figure 1
shows an I2NSF framework [RFC8329] to support network-based security
services. As shown in Figure 1, I2NSF User can use security
functions by delivering high-level security policies, which specify
security requirements the I2NSF user wants to enforce, to the
Security Controller via the Consumer-Facing Interface
[consumer-facing-inf-im][consumer-facing-inf-dm].
The Security Controller receives and analyzes the high-level security
policies from an I2NSF User, and identifies what types of security
capabilities are required to meet these high-level security policies.
The Security Controller then identifies NSFs that have the required
security capabilities, and generates low-level security policies for
each of the NSFs so that the high-level security policies are
eventually enforced by those NSFs. Finally, the Security Controller
sends the generated low-level security policies to the NSFs
[i2nsf-nsf-cap-im][nsf-facing-inf-dm].
The Security Controller requests NSFs to perform low-level security
services via the NSF-Facing Interface. The NSFs are enabled as
Virtual Network Functions (VNFs) on top of virtual machines through
Network Functions Virtualization (NFV) [ETSI-NFV]. In addition, the
Security Controller uses the I2NSF Registration Interface
[registration-inf-im][registration-inf-dm] to communicate with
Developer's Management System (called Developer's Mgmt System) for
registering (or deregistering) the developer's NSFs into (or from)
the NFV system using the I2NSF framework.
The Consumer-Facing Interface between an I2NSF User and the Security
Controller can be implemented using, for example, RESTCONF [RFC8040].
Data models specified by YANG [RFC6020] describe high-level security
policies to be specified by an I2NSF User. The data model defined in
[consumer-facing-inf-dm] can be used for the I2NSF Consumer-Facing
Interface.
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+------------+
| I2NSF User |
+------------+
^
| Consumer-Facing Interface
v
+-------------------+ Registration +-----------------------+
|Security Controller|<-------------------->|Developer's Mgmt System|
+-------------------+ Interface +-----------------------+
^
| NSF-Facing Interface
v
+----------------+ +---------------+ +-----------------------+
| NSF-1 |-| NSF-2 |...| NSF-n |
| (Firewall) | | (Web Filter) | |(DDoS-Attack Mitigator)|
+----------------+ +---------------+ +-----------------------+
Figure 1: I2NSF Framework
The NSF-Facing Interface between the Security Controller and NSFs can
be implemented using NETCONF [RFC6241]. YANG data models describe
low-level security policies for the sake of NSFs, which are
translated from the high-level security policies by the Security
Controller. The data model defined in [nsf-facing-inf-dm] can be
used for the I2NSF NSF-Facing Interface.
The Registration Interface between the Security Controller and the
Developer's Mgmt System can be implemented by RESTCONF [RFC8040].
The data model defined in [registration-inf-dm] can be used for the
I2NSF Registration Interface.
Also, the I2NSF framework can enforce multiple chained NSFs for the
low-level security policies by means of service function chaining
(SFC) techniques for the I2NSF architecture described in
[nsf-triggered-steering].
The following describes a security service scenario using the I2NSF
framework.
3.1. Time-dependent Web Access Control Service
This service scenario assumes that an enterprise network
administrator wants to control the staff members' access to Facebook
during business hours. The following is an example high-level
security policy rule that the administrator requests: Block the staff
members' access to Facebook from 9 am to 6 pm. The administrator
sends this high-level security policy to the security controller,
then the security controller identifies required secuity
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capabilities, e.g., IP address and port number inspection
capabilities and URL inspection capability. In this scenario, it is
assumed that the IP address and port number inspection capabilities
are required to check whether a received packet is an HTTP packet
from a staff member. The URL inspection capability is required to
check whether the target URL of a received packet is facebook.com or
not.
The Security Controller maintains the security capabilities of each
NSF running in the I2NSF system, which have been reported by the
Developer's Management System via the Registation interface. Based
on this information, the Security Controller identifies NSFs that can
perform the IP address and port number inspection and URL inspection.
In this scenario, it is assumed that an NSF of firewall has the IP
address and port number inspection capabilities and an NSF of web
filter has URL inspection capability.
The Security Controller generates low-level security rules for the
NSFs to perform IP address and port number inspection, URL
inspection, and time checking. Specifically, the Security Controller
may interoperate with an access control server in the enterprise
network in order to retrieve the information (e.g., IP address in
use, company identifier (ID), and role) of each employee that is
currently using the network. Based on the retrieved information, the
Security Controller generates low-level security rules to check
whether the source IP address of a received packet matches any one
being used by a staff member. In addition, the low-level security
rules should be able to determine that a received packet is of HTTP
protocol. The low-level security rules for web filter checks that
the target URL field of a received packet is equal to facebook.com.
Finally, the Security Controller sends the low-level security rules
of the IP address and port number inspection to the NSF of firewall
and the low-level rules for URL inspection to the NSF of web filter.
The following describes how the time-dependent web access control
service is enforced by the NSFs of firewall and web filter.
1. A staff member tries to access Fackbook.com during business
hours, e.g., 10 am.
2. The packet is forwarded from the staff member's device to the
firewall, and the firewall checks the source IP address and port
number. Now the firewall identifies the received packet is an
HTTP packet from the staff member.
3. The firewall triggers the web filter to further inspect the
packet, and the packet is forwarded from the firewall to the web
filter. Service Function Chaining (SFC) technology can be
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utilized to support such packet forwarding in the I2NSF framework
[nsf-triggered-steering].
4. The web filter checks the target URL field of the received
packet, and realizes the packet is toward Facebook.com. The web
filter then checks that the current time is in business hours.
If so, the web filter drops the packet, and consequently the
staff member's access to Facebook during business hours is
blocked.
4. I2NSF Framework with SFC
In the I2NSF architecture, an NSF can trigger an advanced security
action (e.g., DPI and DDoS attack mitigation) on a packet based on
the result of its own security inspection of the packet. For
example, a firewall triggers further inspection of a suspicious
packet with DPI. For this advanced security action to be fulfilled,
the suspicious packet should be forwarded from the current NSF to the
successor NSF. Service Function Chaining (SFC) [RFC7665] is a
technology that enables this advanced security action by steering a
packet with multiple service functions (e.g., NSFs), and this
technology can be utilized by the I2NSF architecture to support the
advanced security action.
SFC generally requires classifiers and service function forwarders
(SFFs); classifiers are responsible for determining which service
function path (SFP) (i.e., an ordered sequence of service functions)
a given packet should pass through, according to pre-configured
classification rules, and SFFs perform forwarding the given packet to
the next service function (e.g., NSF) on the SFP of the packet by
referring to their forwarding tables. In the I2NSF architecture with
SFC, the Security Controller can take responsibilities of generating
classification rules for classifiers and forwarding tables for SFFs.
By analyzing high-level security policies from I2NSF users, the
Security Controller can construct SFPs that are required to meet the
high-level security policies, generates classification rules of the
SFPs, and then configures classifiers with the classification rules
over NSF-Facing Interface so that relevant traffic packets can follow
the SFPs. Also, based on the global view of NSF instances available
in the system, the Security Controller constructs forwarding tables,
which are required for SFFs to forward a given packet to the next NSF
over the SFP, and configures SFFs with those forwarding tables over
NSF-Facing Interface.
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+------------+
| I2NSF User |
+------------+
^
| Consumer-Facing Interface
v
+-------------------+ Registration +-----------------------+
|Security Controller|<-------------------->|Developer's Mgmt System|
+-------------------+ Interface +-----------------------+
^ ^
| | NSF-Facing Interface
| |-------------------------
| |
| NSF-Facing Interface |
+-+-+-v-+-+-+-+-+-+ +------v-------+
| +-----------+ | ------>| NSF-1 |
| |Classifier | | | | (Firewall) |
| +-----------+ | | +--------------+
| +-----+ |<-----| +--------------+
| | SFF | | |----->| NSF-2 |
| +-----+ | | | (DPI) |
+-+-+-+-+-+-+-+-+-+ | +--------------+
| .
| .
| .
| +-----------------------+
------>| NSF-n |
|(DDoS-Attack Mitigator)|
+-----------------------+
Figure 2: An I2NSF Framework with SFC
To trigger an advanced security action in the I2NSF architecture, the
current NSF appends a metadata describing the security capability
required for the advanced action to the suspicious packet and sends
the packet to the classifier. Based on the metadata information, the
classifier searches an SFP which includes an NSF with the required
security capability, changes the SFP-related information (e.g.,
service path identifier and service index [RFC8300]) of the packet
with the new SFP that has been found, and then forwards the packet to
the SFF. When receiving the packet, the SFF checks the SFP-related
information such as the service path identifier and service index
contained in the packet and forwards the packet to the next NSF on
the SFP of the packet, according to its forwarding table.
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5. I2NSF Framework with SDN
This section describes an I2NSF framework with SDN for I2NSF
applicability and use cases, such as firewall, deep packet
inspection, and DDoS-attack mitigation functions. SDN enables some
packet filtering rules to be enforced in the network switches by
controlling their packet forwarding rules. By taking advantage of
this capability of SDN, it is possible to optimize the process of
security service enforcement in the I2NSF system.
Figure 3 shows an I2NSF framework [RFC8329] with SDN networks to
support network-based security services. In this system, the
enforcement of security policy rules is divided into the SDN switches
and NSFs. Especially, SDN switches enforce simple packet filtering
rules that can be translated into their packet forwarding rules,
whereas NSFs enforce NSF-related security rules requiring the
security capabilities of the NSFs. For this purpose, the Security
Controller instructs the Switch Controller via NSF-Facing Interface
so that SDN switches can perform the required security services with
flow tables under the supervision of the Switch Controller (i.e., SDN
Controller).
As an example, let us consider two different types of security rules:
Rule A is a simple packet fltering rule that checks only the IP
address and port number of a given packet, whereas rule B is a time-
consuming packet inspection rule for analyzing whether an attached
file being transmitted over a flow of packets contains malware. Rule
A can be translated into packet forwarding rules of SDN switches and
thus be enforced by the switches. In contrast, rule B cannot be
enforced by switches, but it can be enforced by NSFs with anti-
malware capability. Specifically, a flow of packets is forwarded to
and reassembled by an NSF to reconstruct the attached file stored in
the flow of packets. The NSF then analyzes the file to check the
existence of malware. If the file contains malware, the NSF drops
the packets.
In an I2NSF framework with SDN, the Security Controller can analyze
given security policy rules and automatically determine which of the
given security policy rules should be enforced by SDN switches and
which should be enforced by NSFs. If some of the given rules
requires security capabilities that can be provided by SDN switches,
then the Security Controller instructs the Switch Controller via NSF-
Facing Interface so that SDN switches can enforce those security
policy rules with flow tables under the supervision of the Switch
Controller (i.e., SDN Controller). Or if some rules require security
capabilities that can be provided by not SDN switches but NSFs, then
the Security Controller instructs relevant NSFs to enforce those
rules.
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+------------+
| I2NSF User |
+------------+
^
| Consumer-Facing Interface
v
+-------------------+ Registration +-----------------------+
|Security Controller|<-------------------->|Developer's Mgmt System|
+-------------------+ Interface +-----------------------+
^ ^
| | NSF-Facing Interface
| v
| +----------------+ +---------------+ +-----------------------+
| | NSF-1 |-| NSF-2 |...| NSF-n |
| | (Firewall) | | (DPI) | |(DDoS-Attack Mitigator)|
| +----------------+ +---------------+ +-----------------------+
| ^
| |
| v
| +--------+
| | SFF |
| +--------+
| ^
| |
| V SDN Network
+--|----------------------------------------------------------------+
| V NSF-Facing Interface |
| +-----------------+ |
| |Switch Controller| |
| +-----------------+ |
| ^ |
| | SDN Southbound Interface |
| v |
| +--------+ +--------+ +--------+ +--------+ |
| |Switch 1|-|Switch 2|-|Switch 3|......|Switch m| |
| +--------+ +--------+ +--------+ +--------+ |
+-------------------------------------------------------------------+
Figure 3: An I2NSF Framework with SDN Network
The following subsections introduce three use cases for cloud-based
security services: (i) firewall system, (ii) deep packet inspection
system, and (iii) attack mitigation system. [RFC8192]
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5.1. Firewall: 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 this system is as follows:
1. A switch forwards an unknown flow's packet to one of the Switch
Controllers.
2. The Switch Controller forwards the unknown flow's packet to an
appropriate security service application, such as the Firewall.
3. The Firewall analyzes, typically, the headers and contents of the
packet.
4. If the Firewall regards the packet as a malicious one with a
suspicious pattern, it reports the malicious packet to the Switch
Controller.
5. The Switch Controller installs new rules (e.g., drop packets with
the suspicious pattern) into underlying switches.
6. The suspected packets are dropped by these switches.
Existing SDN protocols can be used through standard interfaces
between the firewall application and switches
[RFC7149][ITU-T.Y.3300][ONF-OpenFlow] [ONF-SDN-Architecture].
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 the 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
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
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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 a 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.
5.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security System
A centralized VoIP/VoLTE security system can monitor each VoIP/VoLTE
flow and manage VoIP/VoLTE security rules controlled by a centralized
server for VoIP/VoLTE security service called VoIP Intrusion
Prevention System (IPS). The VoIP/VoLTE security system controls
each switch for the VoIP/VoLTE call flow management by manipulating
the rules that can be added, deleted or modified dynamically.
A centralized VoIP/VoLTE security system can cooperate with a network
firewall to realize VoIP/VoLTE security service. Specifically, a
network firewall performs basic security checks of an unknown flow's
packet observed by a switch. If the network firewall detects that
the packet is an unknown VoIP call flow's packet that exhibits some
suspicious patterns, then it triggers the VoIP/VoLTE security system
for more specialized security analysis of the suspicious VoIP call
packet.
The procedure of VoIP/VoLTE security operations in this system is as
follows:
1. A switch forwards an unknown flow's packet to the Switch
Controller, and the Switch Controller further forwards the
unknown flow's packet to the Firewall for basic security
inspection.
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2. The Firewall analyzes the header fields of the packet, and
figures out that this is an unknown VoIP call flow's signal
packet (e.g., SIP packet) of a suspicious pattern.
3. The Firewall triggers an appropriate security service function,
such as VoIP IPS, for detailed security analysis of the
suspicious signal packet. That is, the firewall sends the packet
to the Service Function Forwarder (SFF) in the I2NSF framework
[nsf-triggered-steering], as shown in Figure 3. The SFF forwards
the suspicious signal packet to the VoIP IPS.
4. The VoIP IPS analyzes the headers and contents of the signal
packet, such as calling number and session description headers
[RFC4566].
5. If, for example, the VoIP IPS regards the packet as a spoofed
packet by hackers or a scanning packet searching for VoIP/VoLTE
devices, it drops the packet. In addition, the VoIP IPS requests
the Switch Controller to block that packet and the subsequent
packets that have the same call-id.
6. The Switch Controller installs new rules (e.g., drop packets)
into underlying switches.
7. The illegal packets are dropped by these switches.
Existing SDN protocols can be used through standard interfaces
between the VoIP IPS application and switches [RFC7149][ITU-T.Y.3300]
[ONF-OpenFlow][ONF-SDN-Architecture].
Legacy hardware based VoIP IPS has some challenges, such as
provisioning time, the granularity of security, expensive cost, and
the establishment of policy. The I2NSF framework can resolve the
challenges through the above centralized VoIP/VoLTE security system
based on SDN as follows:
o Provisioning: The provisioning time of setting up a legacy VoIP
IPS to network is substantial because it takes from some hours to
some days. By managing the network resources centrally, VoIP IPS
can provide more agility in provisioning both virtual and physical
network resources from a central location.
o The granularity of security: The security rules of a legacy VoIP
IPS are compounded considering the granularity of security. The
proposed framework can provide more granular security by
centralizing security control into a switch controller. The VoIP
IPS can effectively manage security rules throughout the network.
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o Cost: The cost of adding VoIP IPS to network resources, such as
routers, gateways, and switches is substantial due to the reason
that we need to add VoIP IPS on each network resource. To solve
this, each network resource can be managed centrally such that a
single VoIP IPS is manipulated by a centralized server.
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 VoIP IPS within a specific
organization network under management. Thus, a centralized view
is helpful to determine security policies for such a network.
5.3. Attack Mitigation: 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 this system is
as follows:
1. A Switch periodically reports an inter-arrival pattern of a
flow's packets to one of the Switch Controllers.
2. The Switch Controller forwards the flow's inter-arrival pattern
to an appropriate security service application, such as DDoS-
attack Mitigator.
3. The DDoS-attack Mitigator analyzes the reported pattern for the
flow.
4. If the 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
Switch Controller.
5. The Switch Controller installs new rules into switches (e.g.,
forward packets with the suspicious inter-arrival pattern with a
dropping probability).
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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-OpenFlow][ONF-SDN-Architecture].
The centralized DDoS-attack mitigation system has challenges similar
to the centralized firewall system. The proposed framework can
resolve the 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
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.
So far this document has described the procedure and impact of the
three use cases for network-based security services using the I2NSF
framework with SDN networks. To support these use cases in the
proposed data-driven security service framework, YANG data models
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described in [consumer-facing-inf-dm], [nsf-facing-inf-dm], and
[registration-inf-dm] can be used as Consumer-Facing Interface, NSF-
Facing Interface, and Registration Interface, respectively, along
with RESTCONF [RFC8040] and NETCONF [RFC6241].
6. I2NSF Framework with NFV
This section discusses the implementation of the I2NSF framework with
Network Functions Virtualization (called NFV).
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+--------------------+
+-------------------------------------------+ | ---------------- |
| I2NSF User (OSS/BSS) | | | NFV | |
+------+------------------------------------+ | | Orchestrator +-+ |
| Consumer-Facing Interface | -----+---------- | |
+------|------------------------------------+ | | | |
| -----+---------- (a) ----------------- | | | | |
| | Security |-------| Developer's | | | | | |
| |Controller(EM)| |Mgmt System(EM)| | | | | |
| -----+---------- ----------------- | | ----+----- | |
| | NSF-Facing Interface | | | | | |
| ----+----- ----+----- ----+----- | | | VNFM(s)| | |
| |NSF(VNF)| |NSF(VNF)| |NSF(VNF)| +-(b)-+ | | |
| ----+----- ----+----- ----+----- | | ----+----- | |
| | | | | | | | |
+------|-------------|-------------|--------+ | | | |
| | | | | | |
+------+-------------+-------------+--------+ | | | |
| NFV Infrastructure (NFVI) | | | | |
| ----------- ----------- ----------- | | | | |
| | Virtual | | Virtual | | Virtual | | | | | |
| | Compute | | Storage | | Network | | | | | |
| ----------- ----------- ----------- | | ----+----- | |
| +---------------------------------------+ | | | | | |
| | Virtualization Layer | +-----+ VIM(s) +------+ |
| +---------------------------------------+ | | | | |
| +---------------------------------------+ | | ---------- |
| | ----------- ----------- ----------- | | | |
| | | Compute | | Storage | | Network | | | | |
| | | Hardware| | Hardware| | Hardware| | | | |
| | ----------- ----------- ----------- | | | |
| | Hardware Resources | | | NFV Management |
| +---------------------------------------+ | | and Orchestration |
+-------------------------------------------+ +--------------------+
(a) = Registration Interface
(b) = Ve-Vnfm Interface
Figure 4: I2NSF Framework Implementation in NFV Reference
Architectural Framework
NFV is a promising technology for improving the elasticity and
efficiency of network resource utilization. In NFV environments,
NSFs can be deployed in the forms of software-based virtual instances
rather than physical appliances. Virtualizing NSFs makes it possible
to rapidly and flexibly respond to the amount of service requests by
dynamically increasing or decreasing the number of NSF instances.
Moreover, NFV technology facilitates flexibly including or excluding
NSFs from multiple security solution vendors according to the changes
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on security requirements. In order to take advantages of the NFV
technology, the I2NSF framework can be implemented on top of an NFV
infrastructure as show in Figure 4.
Figure 4 shows an I2NSF framework implementation based on the NFV
reference architecture that the European Telecommunications Standards
Institute (ETSI) defines [ETSI-NFV]. The NSFs are deployed as
virtual network functions (VNFs) in Figure 4. The Developer's
Management System (DMS) in the I2NSF framework is responsible for
registering capability information of NSFs into the Security
Controller. Those NSFs are created or removed by a virtual network
functions manager (VNFM) in the NFV architecture that performs the
life-cycle management of VNFs. The Security Controller controls and
monitors the configurations (e.g., function parameters and security
policy rules) of VNFs. Both the DMS and Security Controller can be
implemented as the Element Managements (EMs) in the NFV architecture.
Finally, the I2NSF User can be implemented as OSS/BSS (Operational
Support Systems/Business Support Systems) in the NFV architecture
that provides interfaces for users in the NFV system.
The operation procedure in the I2NSF framework based on the NFV
architecture is as follows:
1. The VNFM has a set of virtual machine (VM) images of NSFs, and
each VM image can be used to create an NSF instance that provides
a set of security capabilities. The DMS initially registers a
mapping table of the ID of each VM image and the set of
capabilities that can be provided by an NSF instance created from
the VM image into the Security Controller.
2. If the Security Controller does not have any instantiated NSF
that has the set of capabilities required to meet the security
requirements from users, it searches the mapping table
(registered by the DMS) for the VM image ID corresponding to the
required set of capabilities.
3. The Security Controller requests the DMS to instantiate an NSF
with the VM image ID via VNFM.
4. When receiving the instantiation request, the VNFM first asks the
NFV orchestrator for the permission required to create the NSF
instance, requests the VIM to allocate resources for the NSF
instance, and finally creates the NSF instance based on the
allocated resources.
5. Once the NSF instance has been created by the VNFM, the DMS
performs the initial configurations of the NSF instance and then
notifies the Security Controller of the NSF instance.
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6. After being notified of the created NSF instance, the Security
Controller delivers low-level security policy rules to the NSF
instance for policy enforcement.
The I2NSF framework can be implemented based on the NFV architecture.
Note that the registration of the capabilities of NSFs is performed
through the Registration Interface and the life-cycle management for
NSFs (VNFs) is performed through the Ve-Vnfm interface between the
DMS and VNFM, as shown in Figure 4. More details about the I2NSF
framework based on the NFV reference architecture are described in
[i2nsf-nfv-architecture].
7. Security Considerations
The I2NSF framework with SDN networks in this document is derived
from the I2NSF framework [RFC8329], so the security considerations of
the I2NSF framework should be included in this document. Therefore,
proper secure communication channels should be used the delivery of
control or management messages among the components in the proposed
framework.
This document shares all the security issues of SDN that are
specified in the "Security Considerations" section of [ITU-T.Y.3300].
8. Acknowledgments
This work was supported by Institute for Information & communications
Technology Promotion (IITP) grant funded by the Korea government
(MSIP) (No.R-20160222-002755, Cloud based Security Intelligence
Technology Development for the Customized Security Service
Provisioning).
9. Contributors
I2NSF is a group effort. I2NSF has had a number of contributing
authors. The following are considered co-authors:
o Hyoungshick Kim (Sungkyunkwan University)
o Jinyong Tim Kim (Sungkyunkwan University)
o Hyunsik Yang (Soongsil University)
o Younghan Kim (Soongsil University)
o Jung-Soo Park (ETRI)
o Se-Hui Lee (Korea Telecom)
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o Mohamed Boucadair (Orange)
10. Informative References
[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.
[consumer-facing-inf-dm]
Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares,
"I2NSF Consumer-Facing Interface YANG Data Model", draft-
ietf-i2nsf-consumer-facing-interface-dm-01 (work in
progress), July 2018.
[consumer-facing-inf-im]
Kumar, R., Lohiya, A., Qi, D., Bitar, N., Palislamovic,
S., Xia, L., and J. Jeong, "Information Model for
Consumer-Facing Interface to Security Controller", draft-
kumar-i2nsf-client-facing-interface-im-07 (work in
progress), July 2018.
[ETSI-NFV]
ETSI GS NFV 002 V1.1.1, "Network Functions Virtualization
(NFV); Architectural Framework", October 2013.
[i2nsf-nfv-architecture]
Yang, H. and Y. Kim, "I2NSF on the NFV Reference
Architecture", draft-yang-i2nsf-nfv-architecture-02 (work
in progress), June 2018.
[i2nsf-nsf-cap-im]
Xia, L., Strassner, J., Basile, C., and D. Lopez,
"Information Model of NSFs Capabilities", draft-ietf-
i2nsf-capability-02 (work in progress), July 2018.
[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.
[ITU-T.X.1252]
Recommendation ITU-T X.1252, "Baseline Identity Management
Terms and Definitions", April 2010.
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[ITU-T.X.800]
Recommendation ITU-T X.800, "Security Architecture for
Open Systems Interconnection for CCITT Applications",
March 1991.
[ITU-T.Y.3300]
Recommendation ITU-T Y.3300, "Framework of Software-
Defined Networking", June 2014.
[nsf-facing-inf-dm]
Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin,
"I2NSF Network Security Function-Facing Interface YANG
Data Model", draft-ietf-i2nsf-nsf-facing-interface-data-
model-01 (work in progress), July 2018.
[nsf-triggered-steering]
Hyun, S., Jeong, J., Park, J., and S. Hares, "Service
Function Chaining-Enabled I2NSF Architecture", draft-hyun-
i2nsf-nsf-triggered-steering-06 (work in progress), July
2018.
[ONF-OpenFlow]
ONF, "OpenFlow Switch Specification (Version 1.4.0)",
October 2013.
[ONF-SDN-Architecture]
ONF, "SDN Architecture", June 2014.
[opsawg-firewalls]
Baker, F. and P. Hoffman, "On Firewalls in Internet
Security", draft-ietf-opsawg-firewalls-01 (work in
progress), October 2012.
[registration-inf-dm]
Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF
Registration Interface YANG Data Model", draft-hyun-i2nsf-
registration-dm-05 (work in progress), July 2018.
[registration-inf-im]
Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF
Registration Interface Information Model", draft-hyun-
i2nsf-registration-interface-im-06 (work in progress),
July 2018.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
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[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
[RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined
Networking: A Perspective from within a Service Provider
Environment", RFC 7149, March 2014.
[RFC7665] Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", RFC 7665, October 2015.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, January 2017.
[RFC8192] Hares, S., Lopez, D., Zarny, M., Jacquenet, C., Kumar, R.,
and J. Jeong, "Interface to Network Security Functions
(I2NSF): Problem Statement and Use Cases", RFC 8192, July
2017.
[RFC8300] Quinn, P., Elzur, U., and C. Pignataro, "Network Service
Header (NSH)", RFC 8300, January 2018.
[RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R.
Kumar, "Framework for Interface to Network Security
Functions", RFC 8329, February 2018.
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Appendix A. Changes from draft-ietf-i2nsf-applicability-03
The following changes have been made from draft-ietf-i2nsf-
applicability-03:
o In Section 4, NSF-Facing Interface is used between Security
Controller and Classifier (or SFF) in order to configure
Classifier (or SFF) for SFC-based NSF chaining.
o In Section 6, Developer's Management System is implemented as EM
rather than VNFM in the NFV reference architecture.
Authors' Addresses
Jaehoon Paul Jeong
Department of Software
Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419
Republic of Korea
Phone: +82 31 299 4957
Fax: +82 31 290 7996
EMail: pauljeong@skku.edu
URI: http://iotlab.skku.edu/people-jaehoon-jeong.php
Sangwon Hyun
Department of Computer Engineering
Chosun University
309 Pilmun-daero, Dong-Gu
Gwangju 61452
Republic of Korea
Phone: +82 62 230 7473
EMail: shyun@chosun.ac.kr
Tae-Jin Ahn
Korea Telecom
70 Yuseong-Ro, Yuseong-Gu
Daejeon 305-811
Republic of Korea
Phone: +82 42 870 8409
EMail: taejin.ahn@kt.com
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Susan Hares
Huawei
7453 Hickory Hill
Saline, MI 48176
USA
Phone: +1-734-604-0332
EMail: shares@ndzh.com
Diego R. Lopez
Telefonica I+D
Jose Manuel Lara, 9
Seville 41013
Spain
Phone: +34 682 051 091
EMail: diego.r.lopez@telefonica.com
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