I2NSF S. Hares
Internet-Draft Huawei
Intended status: Standards Track D. Lopez
Expires: August 6, 2017 Telefonica I+D
M. Zarny
vArmour
C. Jacquenet
France Telecom
R. Kumar
Juniper Networks
J. Jeong
Sungkyunkwan University
February 2, 2017
I2NSF Problem Statement and Use cases
draft-ietf-i2nsf-problem-and-use-cases-09
Abstract
This document describes the problem statement for Interface to
Network Security Functions (I2NSF) as well as some companion use
cases.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Problem Space . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Challenges Facing Security Service Providers . . . . . . 5
3.1.1. Diverse Types of Security Functions . . . . . . . . . 5
3.1.2. Diverse Interfaces to Control and Monitor NSFs . . . 6
3.1.3. More Distributed NSFs and vNSFs . . . . . . . . . . . 7
3.1.4. More Demand to Control NSFs Dynamically . . . . . . . 7
3.1.5. Demand for Multi-Tenancy to Control and Monitor NSFs 7
3.1.6. Lack of Characterization of NSFs and Capability
Exchange . . . . . . . . . . . . . . . . . . . . . . 7
3.1.7. Lack of Mechanism for NSFs to Utilize External
Profiles . . . . . . . . . . . . . . . . . . . . . . 8
3.1.8. Lack of Mechanisms to Accept External Alerts to
Trigger Automatic Rule and Configuration Changes . . 8
3.1.9. Lack of Mechanism for Dynamic Key Distribution to
NSFs . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Challenges Facing Customers . . . . . . . . . . . . . . . 10
3.2.1. NSFs from Heterogeneous Administrative Domains . . . 10
3.2.2. Today's Control Requests are Vendor Specific . . . . 11
3.2.3. Difficulty to Monitor the Execution of Desired
Policies . . . . . . . . . . . . . . . . . . . . . . 12
3.3. Difficulty to Validate Policies across Multiple Domains . 13
3.4. Software-Defined Networks . . . . . . . . . . . . . . . . 13
3.5. Lack of Standard Interface to Inject Feedback to NSF . . 14
3.6. Lack of Standard Interface for Capability Negotiation . . 14
4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1. Basic Framework . . . . . . . . . . . . . . . . . . . . . 15
4.2. Access Networks . . . . . . . . . . . . . . . . . . . . . 16
4.3. Cloud Data Center Scenario . . . . . . . . . . . . . . . 19
4.3.1. On-Demand Virtual Firewall Deployment . . . . . . . . 19
4.3.2. Firewall Policy Deployment Automation . . . . . . . . 20
4.3.3. Client-Specific Security Policy in Cloud VPNs . . . . 20
4.3.4. Internal Network Monitoring . . . . . . . . . . . . . 21
4.4. Preventing Distributed DoS, Malware and Botnet attacks . 21
4.5. Regulatory and Compliance Security Policies . . . . . . . 22
5. Management Considerations . . . . . . . . . . . . . . . . . . 22
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
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7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 23
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . 23
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
11. Informative References . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
This document describes the problem statement for Interface to
Network Security Functions (I2NSF) as well as some I2NSF use cases.
A summary of the state of the art in the industry and IETF which is
relevant to I2NSF work is documented in
[I-D.hares-i2nsf-gap-analysis].
The growing challenges and complexity in maintaining a secure
infrastructure, complying with regulatory requirements, and
controlling costs are enticing enterprises into consuming network
security functions hosted by service providers. The hosted security
service is especially attractive to small and medium size enterprises
who suffer from a lack of security experts to continuously monitor
networks, acquire new skills and propose immediate mitigations to
ever increasing sets of security attacks.
According to [Gartner-2013], the demand for hosted (or cloud-based)
security services is growing. Small and medium-sized businesses
(SMBs) are increasingly adopting cloud-based security services to
replace on-premises security tools, while larger enterprises are
deploying a mix of traditional and cloud-based security services.
To meet the demand, more and more service providers are providing
hosted security solutions to deliver cost-effective managed security
services to enterprise customers. The hosted security services are
primarily targeted at enterprises (especially small/medium ones), but
could also be provided to any kind of mass-market customer. As a
result, the Network Security Functions (NSFs) are provided and
consumed in a large variety of environments. Users of NSFs may
consume network security services hosted by one or more providers,
which may be their own enterprise, service providers, or a
combination of both. This document also briefly describes the
following use cases summarized by
[I-D.pastor-i2nsf-merged-use-cases]:
o [I-D.pastor-i2nsf-access-usecases] (I2NSF-Access),
o [I-D.zarny-i2nsf-data-center-use-cases](I2NSF-DC), and
o [I-D.qi-i2nsf-access-network-usecase] (I2NSF-Mobile).
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2. Terminology
AAA: Authentication, Authorization, and Account [RFC2904].
ACL: Access Control List
B2B: Business-to-Business
Bespoke: Something made to fit a particular person, client or
company.
Bespoke security management: Security management which is made to
fit a particular customer.
DC: Data Center
FW: Firewall
IDS: Intrusion Detection System
IPS: Intrusion Protection System
I2NSF: Interface to Network Security Functions
NSF: Network Security Function. An NSF is a function that used to
ensure integrity, confidentiality, or availability of network
communication, to detect unwanted network activity, or to block or
at least mitigate the effects of unwanted activity.
Flow-based NSF: An NSF which inspects network flows according to a
security policy. Flow-based security also means that packets are
inspected in the order they are received, and without altering
packets due to the inspection process (e.g., MAC rewrites, TTL
decrement action, or NAT inspection or changes).
SDN: Software Defined Networking
Virtual NSF: An NSF which is deployed as a distributed virtual
resource.
VPN: Virtual Private Networks
3. Problem Space
The following sub-section describes the problems and challenges
facing customers and security service providers when some or all of
the security functions are no longer physically hosted by the
customer's adminstrative domain.
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Security service providers can be internal or external to the
company. For example, an internal IT Security group within a large
enterprise could act as a security service provider for the
enterprise. In contrast, an enterprise could outsource all security
services to an external security service provider. In this document,
the security service provider function, whether it is internal or
external, will be denoted as "service provider".
The "Customer-Provider" relationship may be between any two parties.
The parties can be in different firms or different domains of the
same firm. Contractual agreements may be required in such contexts
to formally document the customer's security requirements and the
provider's guarantees to fulfill those requirements. Such agreements
may detail protection levels, escalation procedures, alarms
reporting, etc. There is currently no standard mechanism to capture
those requirements.
A service provider may be a customer of another service provider.
It is the objective of the I2NSF work to address these problems and
challenges.
3.1. Challenges Facing Security Service Providers
3.1.1. Diverse Types of Security Functions
There are many types of NSFs. NSFs by different vendors can have
different features and have different interfaces. NSFs can be
deployed in multiple locations in a given network, and perhaps have
different roles.
Below are a few examples of security functions and locations or
contexts in which they are often deployed:
External Intrusion and Attack Protection: Examples of this function
are firewall/ACL authentication, IPS, IDS, and endpoint
protection.
Security Functions in a Demilitarized Zone (DMZ): Examples of this
function are firewall/ACLs, IDS/IPS, one or all of AAA services
NAT, forwarding proxies, and application filtering. These
functions may be physically on-premise in a server provider's
network at the DMZ spots or located in a "virtual" DMZ.
Centralized or Distributed security functions: The security
functions could be deployed in a centralized fashion for ease of
management and network design or in a distributed fashion for
scaled requirement. No matter how a security function is deployed
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and provisioned, it is desirable to have same interface to
provision security policies; otherwise it makes the job of
security administration more complex, requiring knowledge of
firewall and network design.
Internal Security Analysis and Reporting: Examples of this function
are security logs, event correlation, and forensic analysis.
Internal Data and Content Protection: Examples of this function are
encryption, authorization, and public/private key management for
internal database.
Security gateways and VPN concentrators: Examples of these
functions are; IP-sec gateways, Secure VPN concentrators that
handle bridging secure VPNs, and Secure VPN controllers for data
flows.
Given the diversity of security functions, the contexts in which
these functions can be deployed, and the constant evolution of these
functions, standardizing all aspects of security functions is
challenging, and most probably not feasible. Fortunately, it is not
necessary to standardize all aspects. For example, from an I2NSF
perspective, there is no need to standardize how every firewall's
filtering is created or applied. Some features in a specific
vendor's filtering may be unique to the vendor's product so it is not
necessary to standardize these features.
What is needed is a standardized interface to control and monitor the
rule sets that NSFs use to treat packets traversing through these
NSFs. Thus standardizing interfaces will provide an impetus for
standardizing established security functions.
I2NSF may specify some filters, but these filters will be linked to
specific common functionality developed by I2NSF in information
models or data models.
3.1.2. Diverse Interfaces to Control and Monitor NSFs
To provide effective and competitive solutions and services, Security
Service Providers may need to utilize multiple security functions
from various vendors to enforce the security policies desired by
their customers.
Since no widely accepted industry standard security interface to
security NSFs exists today, management of NSFs (device and policy
provisioning, monitoring, etc.) tends to be bespoke security
management offered by product vendors. As a result, automation of
such services, if it exists at all, is also bespoke. Thus, even in
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the traditional way of deploying security features, there is a gap to
coordinate among implementations from distinct vendors. This is the
main reason why mono-vendor security functions are often deployed and
enabled in a particular network segment.
A challenge for monitoring is that an NSF cannot monitor what it
cannot view. Therefore, enabling a security function (e.g., firewall
[I-D.ietf-opsawg-firewalls]) does not mean that a network is
protected. As such, it is necessary to have a mechanism to monitor
and provide execution status of NSFs to security and compliance
management tools. There exist various network security monitoring
vendor-specific interfaces for forensics and troubleshooting.
3.1.3. More Distributed NSFs and vNSFs
The security functions which are invoked to enforce a security policy
can be located in different equipment and network locations.
The European Telecommunications Standards Institute (ETSI) Network
Functions Virtualization (NFV) initiative [ETSI-NFV] creates new
management challenges for security policies to be enforced by
distributed virtual network security functions (vNSF).
A vNSF has higher risk of changes to the state of network connection,
interfaces, or traffic as their hosting Virtual Machines (VMs) are
being created, moved, or decommissioned.
3.1.4. More Demand to Control NSFs Dynamically
In the advent of Software-Defined Networking (SDN)(see
[I-D.jeong-i2nsf-sdn-security-services]), more clients, applications
or application controllers need to dynamically update their security
policies that are enforced by NSFs. The Security Service Providers
have to dynamically update their decision-making process (e.g., in
terms of NSF resource allocation and invocation) upon receiving
security-related requests from their clients.
3.1.5. Demand for Multi-Tenancy to Control and Monitor NSFs
Service providers may need several operational units to control and
monitor the NSFs, especially when NSFs become distributed and
virtualized.
3.1.6. Lack of Characterization of NSFs and Capability Exchange
To offer effective security services, service providers need to
activate various security functions in NSFs or vNSFs manufactured by
multiple vendors. Even within one product category (e.g., firewall),
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security functions provided by different vendors can have different
features and capabilities. For example, filters that can be designed
and activated by a firewall may or may not support IPv6 depending on
the firewall technology.
The service provider's management system (or controller) needs a way
to retrieve the capabilities of service functions by different
vendors so that it could build an effective security solution. These
service function capabilities can be documented in a static manner
(e.g., a file) or via an interface which accesses a repository of
security function capabilities which the NSF vendors dynamically
update.
A dynamic capability registration is useful for automation because
security functions may be subject to software and hardware updates.
These updates may have implications on the policies enforced by the
NSFs.
Today, there is no standard method for vendors to describe the
capabilities of their security functions. Without a common technical
framework to describe the capabilities of security functions, service
providers cannot automate the process of selecting NSFs by different
vendors to accommodate customer's security requirements.
The I2NSF work will focus on developing a standard method to describe
capabilities of security functions.
3.1.7. Lack of Mechanism for NSFs to Utilize External Profiles
Many security functions depend on signature files or profiles to
perform (e.g., IPS/IDS signatures, DDos Open Threat Signaling (DOTS)
filters). Different policies might need different signatures or
profiles. Today, the construction and use of black list databases
can be a win-win strategy for all parties involved. There might be
Open Source-provided signature/profiles (e.g., by Snort, Suricata,
Bro and Kisnet) in the future.
There is a need to have a standard envelope (i.e., the format) to
allow NSFs to use external profiles.
3.1.8. Lack of Mechanisms to Accept External Alerts to Trigger
Automatic Rule and Configuration Changes
NSF can ask the I2NSF security controller to alter specific rules
and/or configurations. For example, a Distributed Denial of Service
(DDoS) alert could trigger a change to the routing system to send
traffic to a traffic scrubbing service to mitigate the DDoS.
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The DDoS protection has the following two parts: a) the configuration
of signaling of open threats and b) DDoS mitigation. DOTS controller
manages the signaling part of DDoS. I2NSF controller(s) would manage
the changing to the affected policies (e.g., forwarding and routing,
filtering, etc.). By monitoring the network alerts from DDoS, I2NSF
can feed an alerts analytics engine that could recognize attacks so
the I2NSF can enforce the appropriate policies.
DDoS mitigation is enhanced if the provider's network security
controller can monitor, analyze, and investigate the abnormal events
and provide information to the client or change the network
configuration automatically.
[I-D.zhou-i2nsf-capability-interface-monitoring] provides details on
how monitoring aspects of the flow-based Network Security Functions
(NSFs) can use the I2NSF interfaces to receive traffic reports and
enforce appropriate policies.
3.1.9. Lack of Mechanism for Dynamic Key Distribution to NSFs
There is a need for a controller to distribute various keys to
distributed NSFs. To distribute various keys, the keys must be
created and managed. While there are many key management methods and
cryptographic suites (e.g., encryption algorithms, key derivation
functions, etc.) and other functions, there is a lack of a standard
interface to provision and manage security associations.
The keys may be used for message authentication and integrity in
order to protect data flows. In addition, keys may be used to secure
the protocol and messages in the core routing infrastructure (see
[RFC4948])
As of now there is not much focus on an abstraction for keying
information that describes the interface between protocols,
operators, and automated key management.
An example of a solution may provide some insight into why the lack
of a mechanism is a problem. If a device had an abstract key table
maintained by security services, a device could use these keys for
routing and seurity devices.
What does this take?
Conceptually, there must be an interface defined for routing/
signaling protocols to make requests for automated key management
when it is being used, and to notify the protocols when keys become
available in the key table. One potential use of such an interface
is to manage IPSec security associations on SDN networks.
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An abstract key service will work under the following conditions:
1. I2NSF needs to design the key table abstraction, the interface
between key management protocols and routing/other protocols, and
possibly security protocols at other layers.
2. For each routing/other protocol, I2NSF needs to define the
mapping between how the protocol represents key material and the
protocol-independent key table abstraction. If protocols share
common mechanisms for authentication (e.g., TCP Authentication
Option), then the same mapping may be reused.
3. Automated Key management must support both symmetric keys and
group keys via the service provided by items 1 and 2.
3.2. Challenges Facing Customers
When customers invoke hosted security services, their security
policies may be enforced by a collection of security functions hosted
in different domains. Customers may not have the security skills to
express sufficiently precise requirements or security policies.
Usually, these customers express the expectations of their security
requirements or the intent of their security policies. These
expectations can be considered customer-level security expectations.
Customers may also desire to express guidelines for security
management. Examples of such guidelines include:
o Which critical communications are to be preserved during critical
events (DOTS working group is standardizing),
o Which hosts are to continue service even during severe security
attacks (DOTS working group is standardizing),
o Reporting of attacks to CERT (MILE working group is
standardizing), and
o Managing network connectivity of systems out of compliance (SACM
working gorup is standardizing).
3.2.1. NSFs from Heterogeneous Administrative Domains
Many medium and large enterprises have deployed various on-premises
security functions which they want to continue to deploy. These
enterprises want to combine local security functions with remote
hosted security functions to achieve more efficient and immediate
counter-measures to both Internet-originated attacks and enterprise
network-originated attacks.
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Some enterprises may only need the hosted security services for their
remote branch offices where minimal security infrastructures/
capabilities exist. The security solution will consist of deploying
NSFs on customer networks and on service provider networks.
3.2.2. Today's Control Requests are Vendor Specific
Customers may utilize NSFs provided by multiple service providers.
Customers need to express their security requirements, guidelines,
and expectations to the service providers. In turn, the service
providers must translate this customer information into customer
security policies and associated configuration tasks for the set of
security functions in their network. Without a standard technical
standard interface that provides a clear technical characterization,
the service provider faces many challenges:
No standard technical characterization and/or APIs: Even for the
most common security services there is no standard technical
characterization or APIs. Most security services are accessible
only through disparate, proprietary interfaces (e.g., portals or
APIs) in whatever format vendors choose to offer. The service
provider must process the customer's input with these widely
varying interfaces.
No standard interface: Without standard interfaces it is complex
for customers to update security policies or integrate the
security functions in their enterprise with the security services
provided by the security service providers. This complexity is
induced by the diversity of the configuration models, policy
models, and supported management interfaces. Without a standard
interface, new innovative security products find a large barrier
to entry into the market.
Managing by scripts de-jour: The current practices rely upon the
use of scripts that generate other scripts which automatically run
to upload or download configuration changes, log information and
other things. These scripts have to be adjusted each time an
implementation from a different vendor technology is enabled on a
provider side.
Lack of immediate feedback: Customers may also require a mechanism
to easily update/modify their security requirements with immediate
effect in the underlying involved NSFs.
Lack of explicit invocation request: While security agreements are
in place, security functions may be solicited without requiring an
explicit invocation means. Nevertheless, some explicit invocation
means may be required to interact with a service function.
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To see how standard interfaces could help achieve faster
implementation time cycles, let us consider a customer who would like
to dynamically allow an encrypted flow with specific port, src/dst
addresses or protocol type through the firewall/IPS to enable an
encrypted video conferencing call only during the time of the call.
With no commonly accepted interface in place, as shown in figure 1,
the customer would have to learn about the particular provider's
firewall/IPS interface and send the request in the provider's
required format.
+------------+
| security |
| management |
| system |
+----||------+
|| proprietary
|| or I2NSF standard
Video: ||
Port 10 +--------+
--------| FW/IPS |-------------
Encrypted +--------+
Video Flow
Figure 1: Example of non-standard vs. standard interface
In contrast, as figure 1 shows, if a firewall/IPS interface standard
exists the customer would be able to send the request to a security
management system without having to do the extensive preliminary
legwork. A standard interface also helps service providers since
they could now offer the same firewall/IPS interface to represent
firewall/IPS services for utilizing products from many vendors. The
result is that the service provider has now abstracted the firewall/
IPS services. The standard interface also helps the firewall/IPS
vendors to focus on their core security functions or extended
features rather than the standard building blocks of a management
interface.
3.2.3. Difficulty to Monitor the Execution of Desired Policies
How a policy is translated into technology-specific actions is hidden
from the customers. However, customers still need ways to monitor
the delivered security service that results from the execution of
their desired security requirements, guidelines and expectations.
Today, there is no standard way for customers to get security service
assurance of their specified security policies properly enforced by
the security functions in the provider domain. The customer also
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lacks the ability to perform "what-if" scenarios to assess the
efficiency of the delivered security service.
It is the objective of the I2NSF work to provide a standard way to
get security service assurance of a customers specific security
policies which provides enough information for customers to perform
"what-if" scenarios to assess efficiency of delivered security
services.
3.3. Difficulty to Validate Policies across Multiple Domains
One key aspect of a hosted security service with security functions
located at different premises is the ability to express, monitor and
verify security policies that combine several distributed security
functions. It is crucial to an effective service to be able to take
these actions via a standard interface. This standard interface
becomes more crucial to the hosted security service when NSFs are
instantiated in Virtual Machines which are sometimes widely
distributed in the network and sometimes are combined together in one
device to perform a set of tasks for delivering a service.
Without standard interfaces and security policy data models, the
enforcement of a customer-driven security policy remains challenging
because of the inherent complexity created by combining the
invocation of several vendor-specific security functions into a
multi-vendor, heterogeneous environment. Each vendor-specific
function may require specific configuration procedures and
operational tasks.
Ensuring the consistent enforcement of the policies at various
domains is also challenging. Standard data models are likely to
contribute to solving that issue.
3.4. Software-Defined Networks
Software-Defined Networks have changed the landscape of data center
designs by introducing overlay networks deployed over ToR switches
that connect to a hypervisor. SDN techniques are meant to improve
the flexibility of workload management without affecting applications
and how they work. Workload can thus be easily and seamlessly
managed across private and public clouds. SDN techniques optimize
resource usage and are now being deployed in various networking
environments, besides cloud infrastructures. Yet, such SDN-inferred
agility may raise specific security issues. For example a security
admin must make sure that a security policy can be enforced
regardless of the location of the workload, thereby raising concerns
about the ability of SDN computation logic to send security policy-
provisioning information to the participating NSFs. A second example
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is workload migration to a public cloud infrastructure which may
raise raise additional security requirements during the migration.
3.5. Lack of Standard Interface to Inject Feedback to NSF
Today, many security functions in the NSF, such as IPS, IDS, DDoS
mitigation and Antivirus, depend heavily on the associated profiles.
NSF devices can perform more effective protection if these NSF
devices have the up-to-date profiles for these functions. Today
there is no standard interface to provide these security profiles for
the NSF.
As more sophisticated threats arise, enterprises, vendors, and
service providers have to rely on each other to achieve optimal
protection. Cyber Threat Alliance (CTA,
http://cyberthreatalliance.org/) is one of those initiatives that aim
at combining efforts conducted by multiple organizations.
The standrd interface to provide security profiles to the NSF should
interwork with the formats which exchange security profiles between
organizations.
One objective of the I2NSF work is to provide this type of standard
interface to security profiles.
3.6. Lack of Standard Interface for Capability Negotiation
There could be situations when the selected NSFs cannot perform the
policies requested by the Security Controller, due to resource
constraints. The customer and security service provider should
negotiate the appropriate resource constraints before the security
service begins. However, unexpected events may happen causing the
NSF to exhaust those negotiated resources. At this point, the NSF
should inform the security controller that the alloted resources have
been exhausted. To support the automatic control in the SDN-era, it
is necessary to have a set of messages for proper notification (and a
response to that notification) between the Security Controller and
the NSFs.
4. Use Cases
Standard interfaces for monitoring and controlling the behavior of
NSFs are essential building blocks for Security Service Providers and
enterprises to automate the use of different NSFs from multiple
vendors by their security management entities. I2NSF may be invoked
by any (authorized) client. Examples of authorized clients are
upstream applications (controllers), orchestration systems, and
security portals.
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4.1. Basic Framework
Users request security services through specific clients (e.g., a
customer application, the Network Service Providers (NSP) Business
Support Systems/Operations Support Systems (BSS/OSS) or management
platform) and the appropriate NSP network entity will invoke the
(v)NSFs according to the user service request. This network entity
is denoted as the security controller in this document. The
interaction between the entities discussed above (client, security
controller, NSF) is shown in Figure 2:
+----------+
+-------+ | | +-------+
| | Interface 1 |Security | Interface 2 | NSF(s)|
|Client <--------------> <------------------> |
| | |Controller| | |
+-------+ | | +-------+
+----------+
Figure 2: Interaction between Entities
Interface 1 is used for receiving security requirements from a client
and translating them into commands that NSFs can understand and
execute. The security controller also passes back NSF security
reports (e.g., statistics) to the client which the security
controller has gathered from NSFs. Interface 2 is used for
interacting with NSFs according to commands (e.g., enact/revoke a
security policy, or distribute a policy), and collecting status
information about NSFs.
Client devices or applications can require the security controller to
add, delete or update rules in the security service function for
their specific traffic.
When users want to get the executing status of a security service,
they can request NSF status from the client. The security controller
will collect NSF information through Interface 2, consolidate it, and
give feedback to the client through Interface 1. This interface can
be used to collect not only individual service information, but also
aggregated data suitable for tasks like infrastructure security
assessment.
Customers may require validating NSF availability, provenance, and
execution. This validation process, especially relevant to vNSFs,
includes at least:
Integrity of the NSF: by ensuring that the NSF is not compromised;
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Isolation: by ensuring the execution of the NSF is self-contained
for privacy requirements in multi-tenancy scenarios.
Provenance of NSF: Customers may need to be provided with strict
guarantees about the origin of the NSF, its status (e.g.,
available, idle, down, and others), and feedback mechanisms so
that a customer may be able to check that a given NSF or set of
NSFs properly conform to the the customer's requirements and
subsequent configuration tasks.
In order to achieve this, the security controller may collect
security measurements and share them with an independent and trusted
third party (via Interface 1) in order to allow for attestation of
NSF functions using the third party added information.
This implies that there may be the following two types of clients
using interface 1: the end-user and and the trusted independent third
party. The I2NSF work may determine that interface 1 creates two
sub-interfaces to support these two types of clients.
4.2. Access Networks
This scenario describes use cases for users (e.g., residential user,
enterprise user, mobile user, and management system) that request and
manage security services hosted in the NSP infrastructure. Given
that NSP customers are essentially users of their access networks,
the scenario is essentially associated with their characteristics as
well as with the use of vNSFs. Figure 3 shows how these virtual
access nodes for different types of customers connect connect through
virtual access nodes an NSF.
The virtual customer premise equipment (vCPE) described in use case
#7 in [NFVUC] requires a model of access virtualization that includes
mobile and residential access networks where the operator may offload
security services from the customer local environment (e.g., device
or terminal) to its own infrastructure.
These use cases define the interaction between the operator and the
vNSFs through automated interfaces, typically by means of Business-
to-Business (B2B) communications.
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Customer + Access + PoP/Datacenter
| | +--------+
| ,-----+--. |Network |
| ,' | `-|Operator|
+-------------+ | /+----+ | |Mgmt Sys|
| Residential |-+------/-+vCPE+----+ +--------+
+-------------+ | / +----+ | \ | :
| / | \ | |
+----------+ | ; +----+ | +----+ |
|Enterprise|---+---+----+ vPE+--+----+ NSF| |
+----------+ | : +----+ | +----+ |
| : | / |
+--------+ | : +----+ | / ;
| Mobile |-+-----\--+vEPC+----+ /
+--------+ | \ +----+ | ,-'
| `--. | _.-'
| `----+----''
+ +
vCPE - virtual customer premise equipment
vPE - virtual provider equipment
vEPC - virtual evolved packet core
(mobile-core network)
Figure 3: NSF and actors
Different access clients may have different service requests:
Residential: service requests for parental control, content
management, and threat management.
Parental control requests may include identity based filters for
web content or usage. Content management may include identifying
and blocking malicious activities from web contents, mail, or
files downloaded. Threat management may include identifying and
blocking botnets or malware.
Enterprise: service requests for enterprise flow security policies
and managed security services
Flow security policies include access to (or isolation from) data
from various internal groups, access to (or isolation from)
various web sites or social media applications, and encryption on
data transferred between corporates sites (main office, enterprise
branch offices, and remote campuses). Managed security services
may include detection and mitigation of external and internal
threats. External threats can include application or phishing
attacks, malware, botnet, DDoS, and others. Internal threats (aka
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lateral threats) can include detecting programs moving from one
enterprise site to another without permission.
Service Provider: Service requests for policies that protect
service provider networks against various threats (including DDoS,
botnets and malware). Such policies are meant to securely and
reliably deliver contents (e.g., data, voice, and video) to
various customers, including residential, mobile and corporate
customers. These security policies are also enforced to guarantee
isolation between multiple tenants, regardless of the nature of
the corresponding connectivity services.
Mobile: service requests from interfaces which monitor and ensure
user quality of experience, content management, parental controls,
and external threat management.
Content management for the mobile device includes identifying and
blocking malicious activities from web contents, mail, files
uploaded/downloaded. Threat management for infrastructure
includes detecting and removing malicious programs such as botnet,
malware, and other programs that create distributed DoS attacks).
Some access customers may not care about which NSFs are utilized to
achieve the services they requested. In this case, provider network
orchestration systems can internally select the NSFs (or vNSFs) to
enforce the security policies requested by the clients. Other access
customers, especially some enterprise customers, may want to get
their dedicated NSFs (most likely vNSFs) for direct control purposes.
In this case, here are the steps to associate vNSFs to specific
customers:
vNSF Deployment: The deployment process consists in instantiating
an NSF on a Virtualization Infrastructure (NFVI), within the NSP
administrative domain(s) or with other external domain(s). This
is a required step before a customer can subscribe to a security
service supported in the vNSF.
vNSF Customer Provisioning: Once a vNSF is deployed, any customer
can subscribe to it. The provisioning lifecycle includes the
following:
* Customer enrollment and cancellation of the subscription to a
vNSF;
* Configuration of the vNSF, based on specific configurations, or
derived from common security policies defined by the NSP.
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* Retrieval of the vNSF functionalities, extracted from a
manifest or a descriptor. The NSP management systems can
demand this information to offer detailed information through
the commercial channels to the customer.
4.3. Cloud Data Center Scenario
In a data center, network security mechanisms such as firewalls may
need to be dynamically added or removed for a number of reasons.
These changes may be explicitly requested by the user, or triggered
by a pre-agreed upon demand level in the Service Level Agreement
(SLA) between the user and the provider of the service. For example,
the service provider may be required to add more firewall capacity
within a set of timeframes whenever the bandwidth utilization hits a
certain threshold for a specified period. This capacity expansion
could result in adding new instances of firewalls on existing
machines or provisioning a completely new firewall instance in a
different machine.
The on-demand, dynamic nature of security service delivery
essentially encourages that the network security "devices" be in
software or virtual form factors, rather than in a physical appliance
form. This requirement is a provider-side concern. Users of the
firewall service are agnostic (as they should) as to whether or not
the firewall service is run on a VM or any other form factor.
Indeed, they may not even be aware that their traffic traverses
firewalls.
Furthermore, new firewall instances need to be placed in the "right
zone" (domain). The issue applies not only to multi-tenant
environments where getting the tenant in the right domain is of
paramount importance, but also in environments owned and operated by
a single organization with its own service segregation policies. For
example, an enterprise may mandate that firewalls serving Internet
traffic and B2B traffic be separated. Another example is that IPS/
IDS services for investment banking and non-banking traffic may be
separated for regulatory reasons.
4.3.1. On-Demand Virtual Firewall Deployment
A service provider-operated cloud data center could serve tens of
thousands of clients. Clients' compute servers are typically hosted
on VMs, which could be deployed across different server racks located
in different parts of the data center. It is often not technically
and/or financially feasible to deploy dedicated physical firewalls to
suit each client's security policy requirements, which can be
numerous. What is needed is the ability to dynamically deploy
virtual firewalls for each client's set of servers based on
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established security policies and underlying network topologies.
Figure 4 shows an example toipology of virtual firewalls within a
data center.
---+-----------------------------+-----
| |
+---+ +-+-+
|vFW| |vFW|
+---+ +-+-+
| Client #1 | Client #2
---+-------+--- ---+-------+---
+-+-+ +-+-+ +-+-+ +-+-+
|vM | |vM | |vM | |vM |
+---+ +---+ +---+ +---+
Figure 4: NSF in Data Centers
4.3.2. Firewall Policy Deployment Automation
Firewall rule setting is often a time consuming, complex and error-
prone process even within a single organization/enterprise framework.
It becomes far more complex in provider-owned cloud networks that
serve myriads of customers.
Firewall rules today are highly tied with ports and addresses that
identify traffic. This makes it very difficult for clients of cloud
data centers to construct rules for their own traffic as the clients
only see the virtual networks and the virtual addresses. The
customer-visible virtual networks and addresses may be different from
the actual packets traversing the FWs.
Even though most vendors support similar firewall features, the
actual rule configuration keywords are different from vendors to
vendors, making it difficult for automation. Automation works best
when it can leverage a common set of standards that will work across
NSFs by multiple vendors. Without automation, it is virtually
impossible for clients to dynamically specify their desired rules for
their traffic.
Another feature that aids automation of firewalls that must be
covered in automation is dynamic key management.
4.3.3. Client-Specific Security Policy in Cloud VPNs
Clients of service provider-operated cloud data centers not only need
to secure Virtual Private Networks (VPNs), but also virtual security
functions that apply the clients' security policies. The security
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policies may govern communication within the clients' own virtual
networks as well as communication with external networks. For
example, VPN service providers may need to provide firewall and other
security services to their VPN clients. Today, it is generally not
possible for clients to dynamically view (let alone change) what,
where and how security policies are implemented on their provider-
operated clouds. Indeed, no standards-based framework exists to
allow clients to retrieve/manage security policies in a consistent
manner across different providers.
As described above, the dynamic key management is critical for the
securing the VPN and the distribution of policies.
4.3.4. Internal Network Monitoring
There are many types of internal traffic monitors that may be managed
by a security controller. This includes a new class of services
referred to as Data Loss Prevention (DLP), or Reputation Protection
Services (RPS). Depending on the class of event, alerts may go to
internal administrators, or external services.
4.4. Preventing Distributed DoS, Malware and Botnet attacks
In the Internet where everything is connected, preventing unwanted
traffic that may cause a Denial of Service (DoS) attack or a
distributed DoS (DDoS) attack has become a challenge. Similarly, a
network could be exposed to malware attacks and become an attack
vector to jeopardize the operation of other networks, by means of
remote commands for example. Many networks such as Internet of
Things (IoT) networks, Information-Centric Networks (ICN), Content
Delivery Networks (CDN), Voice over IP packet networks (VoIP), and
Voice over LTE (VoLTE) are also exposed to such attacks.
In order for organizations to better secure their networks against
these kind of attacks, the I2NSF framework should provide a client-
side interface that is use case-independent and technology-agnostic.
Technology-agnostic is to is defined to be generic, technology
independent, and able to support multiple protocols and data models.
For example, such an I2NSF interface could be used to provision
security policy configuration information that looks for specific
malware signatures. Similarly, botnet attacks could be easily
prevented by provisioing security policies using the I2NSF client-
side interface that prevent access to botnet command and control
servers.
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4.5. Regulatory and Compliance Security Policies
Organizations are not only supposed to protect their networks against
attacks, but they should also adhere to various industry regulations:
any organization that falls under a specific regulation like Payment
Card Industry (PCI)-Data Security Standard (DSS) [PCI-DSS] for the
payment industry or Health Insurance Portability and Accountability
Act [HIPAA] for the healthcare industry must be able to isolate
various kinds of traffic. They must also show records of their
security policies whenever audited.
The I2NSF client-side interface could be used to provision regulatory
and compliance-related security policies. The security controller
would keep track of when and where a specific policy is applied and
if there is any policy violation; this information can be provided in
the event of an audit as a proof that traffic is isolated between
specific endpoints, in full compliance with the required regulations.
5. Management Considerations
Management of NSFs usually include the following:
o Lifecycle managment and resource management of NSFs,
o Device configuration, such as address configuration, device
internal attributes configuration, etc.,
o Signaling of events, notifications and changes, and
o Policy rule provisioning.
I2NSF will only focus on the policy provisioning part of NSF
management.
6. IANA Considerations
No IANA considerations exist for this document.
7. Security Considerations
Having a secure access to control and monitor NSFs is crucial for
hosted security services. An I2NSF security controller raises new
security threats. It needs to be resilient to attacks and quickly
recover from attacks. Therefore, proper secure communication
channels have to be carefully specified for carrying controlling and
monitoring traffic between the NSFs and their management entity (or
entities).
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In addition, the Flow security policies specified by customers can
conflict with providers' internal security policies which may allow
unauthorized traffic or unauthorized changes to flow polices (e.g.
customers changing flow policies that do not belong to them).
Therefore, it is crucial to have proper AAA [RFC2904] to authorize
access to the network and access to the I2NSF management stream.
8. Contributors
I2NSF is a group effort. The following people actively contributed
to the initial use case text: Xiaojun Zhuang (China Mobile), Sumandra
Majee (F5), Ed Lopez (Fortinet), and Robert Moskowitz (Huawei).
9. Contributing Authors
I2NSF has had a number of contributing authors. The following are
contributing authors:
o Linda Dunbar (Huawei),
o Antonio Pastur (Telefonica I+D),
o Mohamed Boucadair (France Telecom),
o Michael Georgiades (Prime Tel),
o Minpeng Qi (China Mobile),
o Shaibal Chakrabarty (US Ignite),
o Nic Leymann (Deutsche Telekom),
o Anil Lohiya (Juniper),
o David Qi (Bloomberg),
o Hyoungshick Kim (Sungkyunkwan University),
o Jung-Soo Park (ETRI),
o Tae-Jin Ahn (Korea Telecom), and
o Se-Hui Lee (Korea Telecom).
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10. Acknowledgements
This document was supported by Institute for Information and
communications Technology Promotion (IITP) funded by the Korea
government (MSIP) [R0166-15-1041, Standard Development of Network
Security based SDN].
11. Informative References
[ETSI-NFV]
ETSI GS NFV 002 V1.1.1, , "Network Functions
Virtualisation (NFV); Architectural Framework", October
2013.
[Gartner-2013]
Messmer, E., "Gartner: Cloud-based security as a service
set to take off", October 2013.
[HIPAA] US Congress, , "HEALTH INSURANCE PORTABILITY AND
ACCOUNTABILITY ACT OF 1996 (Public Law 104-191)", August
1996, .
[I-D.hares-i2nsf-gap-analysis]
Hares, S., Zhang, D., Moskowitz, R., and H. Rafiee,
"Analysis of Existing work for I2NSF", draft-hares-i2nsf-
gap-analysis-01 (work in progress), December 2015.
[I-D.ietf-opsawg-firewalls]
Baker, F. and P. Hoffman, "On Firewalls in Internet
Security", draft-ietf-opsawg-firewalls-01 (work in
progress), October 2012.
[I-D.jeong-i2nsf-sdn-security-services]
Jeong, J., Kim, H., Jung-Soo, P., Ahn, T., and s.
sehuilee@kt.com, "Software-Defined Networking Based
Security Services using Interface to Network Security
Functions", draft-jeong-i2nsf-sdn-security-services-05
(work in progress), July 2016.
[I-D.pastor-i2nsf-access-usecases]
Pastor, A. and D. Lopez, "Access Use Cases for an Open OAM
Interface to Virtualized Security Services", draft-pastor-
i2nsf-access-usecases-00 (work in progress), October 2014.
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[I-D.pastor-i2nsf-merged-use-cases]
Pastor, A., Lopez, D., Wang, K., Zhuang, X., Qi, M.,
Zarny, M., Majee, S., Leymann, N., Dunbar, L., and M.
Georgiades, "Use Cases and Requirements for an Interface
to Network Security Functions", draft-pastor-i2nsf-merged-
use-cases-00 (work in progress), June 2015.
[I-D.qi-i2nsf-access-network-usecase]
Wang, K. and X. Zhuang, "Integrated Security with Access
Network Use Case", draft-qi-i2nsf-access-network-
usecase-02 (work in progress), March 2015.
[I-D.zarny-i2nsf-data-center-use-cases]
Zarny, M., Leymann, N., and L. Dunbar, "I2NSF Data Center
Use Cases", draft-zarny-i2nsf-data-center-use-cases-00
(work in progress), October 2014.
[I-D.zhou-i2nsf-capability-interface-monitoring]
Zhou, C., Xia, L., Boucadair, M., and J. Xiong, "The
Capability Interface for Monitoring Network Security
Functions (NSF) in I2NSF", draft-zhou-i2nsf-capability-
interface-monitoring-00 (work in progress), October 2015.
[NFVUC] ETSI GS NFV 001 V1.1.1, , "ETSI NFV Group Specification,
Network Functions Virtualization (NFV) Use Cases", October
2013.
[PCI-DSS] PCI Security Council, , "Payment Card Industry (PCI) Data
Security Standard Requirements and Security Assessment
Procedures (version 3.2)", April 2016,
.
[RFC2904] Vollbrecht, J., Calhoun, P., Farrell, S., Gommans, L.,
Gross, G., de Bruijn, B., de Laat, C., Holdrege, M., and
D. Spence, "AAA Authorization Framework", RFC 2904,
DOI 10.17487/RFC2904, August 2000,
.
[RFC4948] Andersson, L., Davies, E., and L. Zhang, "Report from the
IAB workshop on Unwanted Traffic March 9-10, 2006",
RFC 4948, DOI 10.17487/RFC4948, August 2007,
.
Authors' Addresses
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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
Don Ramon de la Cruz, 82
Madrid 28006
Spain
Email: diego.r.lopez@telefonica.com
Myo Zarny
vArmour
800 El Camino Real, Suite 3000
Mountain View, CA 94040
USA
Email: myo@varmour.com
Christian Jacquenet
France Telecom
Rennes, 35000
France
Email: Christian.jacquenet@orange.com
Rakesh Kumar
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
USA
Email: rkkumar@juniper.net
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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
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