wdiff draft-ietf-i2nsf-client-facing-interface-req-00.txt draft-ietf-i2nsf-client-facing-interface-req-01.txt

I2NSF Working Group R. Kumar
Internet-Draft A. Lohiya
Intended status: Informational Juniper Networks
Expires: May 1, October 28, 2017 D. Qi
Bloomberg
N. Bitar
S. Palislamovic
Nokia
L. Xia
Huawei
October 28, 2016
April 26, 2017

Requirements for Client-Facing Interface to Security Controller
draft-ietf-i2nsf-client-facing-interface-req-00
draft-ietf-i2nsf-client-facing-interface-req-01

Abstract

This document captures the requirements for the client-facing Client-Facing interface to the security controller.
Security Controller. The interfaces are based on
user interface is expressed using objects and
constructs understood by a security admin instead of a Security Admin as opposed to vendor or
a
device specific mechanism requiring deep knowledge of expressions associated with individual
products product and features.
feature. This document identifies the a broad set of requirements needed
to enforce the user-construct oriented policies onto network express security functions (NSFs) irrespective of how those functions policies based on User-constructs which are
realized. The function may well
understood by User Community. This gives ability to decouple policy
definition from policy enforcement on a specific element, be it a
physical or virtual in nature and may
be implemented in networking or dedicated appliances. virtual.

Status of This Memo

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This Internet-Draft will expire on May 1, October 28, 2017.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in this Document . . . . . . . . . . . . . . 4
3. Guiding principles principle for definition of Client-Facing Interfaces Interface defintion . . . 5
3.1. User-construct based modeling . . . . . . . . . . . . . . 5
3.2. Basic rules for client interface Client-Facing Interface definition . . . . . . . 6
3.3. Deployment Models for Implementing Security Policies . . 7
4. Functional Requirements for the Client-Facing Interface . . . 10
4.1. Requirement for Multi-Tenancy in client interface . . . . 11
4.2. Requirement for Authentication and Authorization of
client interface . . . . . . . . . . . . . . . . . . . . 12
4.3. Requirement for Role-Based Access Control (RBAC) in
client interface . . . . . . . . . . . . . . . . . . . . 12
4.4. Requirement to protect client interface from attacks . . 12
4.5. Requirement to protect client interface from
misconfiguration . . . . . . . . . . . . . . . . . . . . 13 12
4.6. Requirement to manage policy lifecycle with diverse needs 13
4.7. Requirement to define dynamic policy Endpoint group . . . 14
4.8. Requirement to express rich set of policy rules . . . . . 15
4.9. Requirement to express rich set of policy actions . . . . 16
4.10. Requirement to express policy in a generic model . . . . 18
4.11. Requirement to detect and correct policy conflicts . . . 18
4.12. Requirement for backward compatibility . . . . . . . . . 18
4.13. Requirement for Third-Party integration . . . . . . . . . 19 18
4.14. Requirement to collect telemetry data . . . . . . . . . . 19
5. Operational Requirements for the Client-Facing Interface . . 19
5.1. API Versioning . . . . . . . . . . . . . . . . . . . . . 19
5.2. API Extensiblity . . . . . . . . . . . . . . . . . . . . 20 19
5.3. APIs and Data Model Transport . . . . . . . . . . . . . . 20
5.4. Notification . . . . . . . . . . . . . . . . . . . . . . 20
5.5. Affinity . . . . . . . . . . . . . . . . . . . . . . . . 20
5.6. Test Interface . . . . . . . . . . . . . . . . . . . . . 20

6. Security Considerations . . . . . . . . . . . . . . . . . . . 20
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7.
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
8.
9. Normative References . . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21

1. Introduction

Programming security policies in a network has been a fairly complex
task that often requires very deep knowledge of vendor specific
devices.
device and features. This has been the biggest challenge for both service
providers
Service Provider and enterprises, Enterprise, henceforth named as security administrator Security Admin
in this document. The This challenge is further amplified due to network
virtualization with security appliances functions deployed in physical and
virtual form factor factor, henceforth named as network security function
(NSF) in this document, from a
wide variety of vendors; each vendor have their own multiple vendors with proprietary
interfaces to express security policies on their devices.
interface.

Even if a security administrator Security Admin deploys a single vendor solution with one or
more security appliances across its entire network, it is still very
difficult to manage security policies due to complexity of security
features, and difficulty in mapping of business requirement requirements to vendor specific
configuration. The security administrator Security Admin may use
either vendor provided CLIs or management system with some
abstraction
systems to help provision and manage security policies. But, the single
vendor approach is highly restrictive in today's network for
the
following reasons:

o The security administrator cannot An organization may not be able to rely on a single vendor because
one vendor
the changing security requirements may not be able to keep up align with their security
requirements or specific deployment model. vendor's
release cycle.

o A large organization may have a presence across different sites
and regions; which means, it may not be possible to deploy same
solution from single the same vendor due to because of regional regulatory requirement or
organizational and
compliance policy.

o If and when security administrator an organization migrates from one vendor to another,
it is almost impossible to migrate security policies from one
vendor solution to another without complex and time consuming manual
workflows.

o Security administrators An organization may deploy various multiple network security functions in
virtual or and physical forms to attain the flexibility, elasticity,
performance,
performance scale, and operational efficiency they require.
Practically, that often requires different sources (vendor, open
source) to get the best of breed for any such security function.

o The security administrator might An organization may choose various devices all or network
services (such part of their assets such as
routers, switches, firewall devices, firewalls, and
overlay-networks) overlay-networks as policy
enforcement points for security policies.

This my operational and cost efficiency. It would
be highly complex to manage policy enforcement with different tool
set for reason (such as network design simplicity, cost,
most-effective place, scale and performance). each type of device.

In order to ease the facilitate deployment of security policies across
different
vendors and devices, vendor provided NSFs, the Interface to Network Security
Functions (I2NSF) working group in the IETF is defining a client-facing Client-
Facing interface from the security controller to clients Security Controller [I-D. ietf-i2nsf-
framework] ietf-i2nsf-framework]
[I-D. ietf-i2nsf-terminology]. Deployment facilitation should be
agnostic to the type of device, be it physical or virtual, or type of the policy, be it dynamic or static.
enforcement point. Using these interfaces, it would become becomes possible to
write different kinds of
application security management applications (e.g. GUI
portal, template engine, etc.) allowing Security Admin to control the
implementation of express
security policies on in an abstract form with choice of wide variety of
NSF for policy enforcement. The implementation of security functional elements,
though how these
management applications are implemente are or controller is completely out of the scope
of the I2NSF working group, which is only focused on the
interfaces. interface
definition.

This document captures the requirements for the client-facing Client-Facing interface
that can be easily used by security administrators Security Admin without
knowledge of a need for
expertise in vendor and device specific security devices or features. feature set. We refer to
this as "user-construct" "User-construct" based interfaces. To further clarify, in
the scope of this document, the "user-construct" "User-construct" here does not mean
some free-from natural language input or an abstract intent such as
"I want my traffic secure" or "I don't want DDoS attacks in my
network"; rather the user-construct User-construct here means that policies are
described using client-oriented expressions such as application names, application
groups, device groups, user groups etc. with a vocabulary of verbs
(e.g., drop, tap, throttle), prepositions, conjunctions,
conditionals, adjectives, and nouns instead of using standard
n-tuples from the packet header.

2. Conventions Used in this Document

BSS: Business Support System

CLI: Command Line Interface

CMDB: Configuration Management Database

Controller: Used interchangeably with Service Provider Security Controller or
management system throughout this document

CRUD: Create, Retrieve, Update, Delete
FW: Firewall

GUI: Graphical User Interface

IDS: Intrusion Detection System

IPS: Intrusion Protection System

LDAP: Lightweight Directory Access Protocol

NSF: Network Security Function, defined by
[I-D.ietf-i2nsf-problem-and-use-cases]

OSS: Operation Support System

RBAC: Role Based Access Control

SIEM: Security Information and Event Management

URL: Universal Resource Locator

vNSF: Refers to NSF being instantiated on Virtual Machines

3. Guiding principles principle for definition of Client-Facing Interfaces

The "Client-Facing Interface" ensures Interface defintion

Client-Facing Interface must ensure that a security administrator Security Admin can deploy
any device NSF from any vendor and should still be able to use a the same
consistent interface. In essence, this interface gives ability to
security admins must allow a
Security Admin to express their security policies independent of how
security functions NSFs
are implemented in their deployment. Henceforth, in this document,
we use "security policy management interface" interchangeably when we
refer to the client-facing Client-Facing interface.

3.1. User-construct based modeling

Traditionally, security policies have been expressed using
proprietary interfaces. These interface. The interface are is defined by a vendor
either based on CLI
proprietary command line text or a GUI system; but more often these interfaces
are built using vendor based system with
implementation specific networking construct constructs such IP address, protocol and application constructs with
L4-L7 information. This requires security operator Security Admin to translate their oragnzational
business objectives into actionable security policies on the device using vendor specific configuration. provided constructs in order to
express a security policy. But, this alone is not sufficient to
render policies a policy in the network as operator also need to identify the
device in network; the admin must also understand
network topology where and application design to locate a specific policy need
enforcement point to make sure policy is effective. This may be enforced
highly manual task based on specific network design and may become
unmanageable in
a complex environment with potenial multiple policy enforcement
points. virtualized networks.

The User-construct based framework defines does not rely on lower level
semantics due to problem explained above, but rather uses higher
level constructs such as user-
group, application-group, device-group and location-group. The
security admin User-group, Application-group, Device-group,
Location-group, etcetera. A Security Admin would use these
constructs to express a security policy instead of proprietary vendor
implementation or feature specific constructs. The policy defined in
such a manner is referred to user-construct User-construct based policies in this
draft. The idea is to enable security admin Security Admin to use constructs they
understand best in expressing security policies; policies which simplify their
tasks and help avoiding human errors in complex security
provisioning.

3.2. Basic rules for client interface Client-Facing Interface definition

The basic rules in defining the client-facing Client-Facing interfaces are as
follows:

o Not depending dependent on particular network Network topology or the actual NSF location
in the network

o Not requiring the exact deep knowledge of the concrete proprietary features and
capabilities supported in the deployed NSFsa&#128;&#157;

o Independent of the nature of the function NSF type that will apply implement the
expressed policies user security
policy be it a stateful firewall,IDP, IDS, Router, Switch

o Declarative/Descriptive model instead of Imperative/Prescriptive
model - What security policies policy need to be enforced (declarative)
instead of how they would be actually it is implemented (imperative)

o Not depending dependent on any specific vendor implementation or form-factor
(physical, virtual) of the NSF

o Not depending dependent on how a NSF becomes operational - Network
connectivity and other hosting requirements.

o Not depending dependent on NSF control plane implementation (if there is
one) E.g., cluster of NSFs active as one unified service for scale
and/ or resilience.

o Not depending on specific data plane implementation of NSF i.e.
Encapsulation, Service function chains.

Note that the rules stated above only apply to the client-facing
interface where Client-Facing
interface, which a user will define would use to express a high level policy.
These rules do not apply to the lower layers e.g. security controller Security
Controller that convert the higher level policies into lower level
constructs. The lower layers may still need some intelligence such
as topology awareness, capability of the NSF and its functions,
supported encapsulations etc. to convert and apply the policies
accurately on the NSF devices. NSF.

3.3. Deployment Models for Implementing Security Policies

Traditionally, medium and larger operators large Enterprise deploy management systems
to manage their statically-defined statically defined security policies. This approach
may not be suitable nor sufficient for modern automated and dynamic
data centers that are largely virtualized and rely on various
management systems and controllers to dynamically implement security
policies over any types of resources. NSF.

There are two different deployment models in which the client-facing Client-Facing
interface referred to in this document could be implemented. These
models have no direct impact on the client-facing Client-Facing interface, but
illustrate the overall security policy and management framework and
where the various processing functions reside. These models are:

a. Management Policy management without an explicit management system for
control of
devices and NSFs. In this deployment, the security controller Security Controller acts as
a NSF policy management system that system; it takes information passed over the client security policy Client-
Facing interface and translates into data on the I2NSF NSF-facing
interface. The I2NSF
interfaces are NSF-Facing interface is implemented by security device/function vendors.
This NSF
vendors; this would usually be done by having an I2NSF agent
embedded in the security device or NSF. This deployment model is shown in Figure 1.

------------- -------------
| I2NSF Agent | | I2NSF Agent |
|-------------| |-------------|
| |---| |
| NSF | | NSF |
NSFs | | | |
(virtual -------------\ /-------------
and | \ / |
physical) | X |
| / \ |
-------------/ \-------------
| I2NSF Agent | | I2NSF Agent |
|-------------| |-------------|
| |---| |
| NSF | | NSF |
| | | |
------------- -------------

Figure 1: Deployment without Management System

b. Management Policy management with an explicit management system for control
of
devices and NSFs. This model is similar to the model above except that security controller
Security Controller interacts with a vendor's dedicated
management system which could either that proxy I2NSF NSF-facing NSF-Facing interfaces or could provide a layer where security devices or
NSFs do as NSF
may not support an I2NSF agent NSF-Facing interface. This is a useful model to process I2NSF NSF-facing
interfaces.
support legacy NSF. This deployment model is shown in Figure 2.

------------- -------------
| |---| |
| NSF | | NSF |
NSFs | | | |
(virtual -------------\ /-------------
and | \ / |
physical) | X |
| / \ |
-------------/ \-------------
| |---| |
| NSF | | NSF |
| | | |
------------- -------------

Figure 2: Deployment with Management System or I2NSF Proxy Agent

Although the deployment models discussed here don't necessarily
affect the client security policy definition of Client-Facing interface, they do give an
overall context for defining a security policy interface based on
abstraction.

4. Functional Requirements for the Client-Facing Interface

As stated in the guiding principles principle for defining the I2NSF client-facing Client-
Facing interface, the security policies and the client-facing Client-Facing
interface shall be defined from a user/client user's or client's perspective and
abstracted away from the type of NSF, NSF specific implementation,
controller implementation, NSF network topology, NSF interfaces, controller NSF-facing
interfaces. NSF-Facing
interface. Thus, the security policy definition shall be
declarative, expressing the user construct, expressed using User-construct, and driven by how
security administrators
Security Admin view security policies from the definition, communication
and deployment perspective.

The security controller's

Security Controller's' implementation is outside the scope of this
document and the I2NSF working group.

In order to express and build security policies, high level
requirements
requirement for the client-facing are Client-Facing interface is as follows:

o Multi-Tenancy

o Authentication and Authorization

o Role-Based Access Control (RBAC)

o Protection from Attacks

o Protection from Misconfiguration

o Policy Lifecycle Management

o Dynamic Policy Endpoint Groups

o Policy Rules

o Policy Actions
o Generic Policy Model

o Policy Conflict Resolution

o Backward Compatibility

o Third-Party Integration

o Telemetry Data

The above requirements are by no means a complete list and may not be
sufficient for all use-cases and all operators, Security Admins, but should be a
good starting point for a wide variety of use-cases in Service
Provider and Enterprise networks.

4.1. Requirement for Multi-Tenancy in client interface

A security administrator that uses security policies Security Admin may have internal tenants and would like to have might want a framework
wherein each tenant manages its own security policies with isolation
from other tenants.

An operator

A Security Admin may be a cloud service provider with multi-tenant
deployments,
deployment, where each tenant is a different customer. Each tenant
or customer must be allowed to manage its own security policies.

It should be noted that tenants may have their own tenants, so a
recursive relation may exist. For instance, a tenant in a cloud
service provider Cloud
Service Provider may have multiple departments or organizations that
need to manage their own security rules. rules for compliance.

Some key concepts are listed below and used throughout the document
hereafter:

Policy-Tenant: An entity that owns and manages the security Policies policies
applied on its resources.

Policy-Administrator: A user authorized to manage the security
policies for a Policy-Tenant.

Policy-User: A user within a Policy-Tenant who is authorized to
access certain resources of that tenant according to the
privileges assigned to it.

4.2. Requirement for Authentication and Authorization of client
interface

Security administrators Admin MUST authenticate to and be authorized by the
security controller Security
Controller before they are able to issue control commands and any
policy data exchange commences. commands.

There must be methods defined for the Policy-Administrator to be
authenticated and authorized to use the security controller. Security Controller. There are
several authentication methods available such as OAuth, XAuth and
X.509 certificate based. The based; the authentication scheme between Policy-
Administrator and security controller may also be mutual instead of
one-way. Any specific method may be determined or single-
sided based on
organizational and deployment business needs and outside the scope of I2NSF. In
addition, there must be a method to o authorize the Policy-
Administrator for performing Policy-Administrator
to perform certain action. It should be noted that, depending on the deployment model, Policy-Administrator Policy-
Administrator authentication and authorization to perform actions communicated to
the controller
could be performed as part of Security Controller or outside; this document does
not mandate any specific implementation but requires that such a portal or another
system prior to communication the action to the controller.
scheme must be implemented.

4.3. Requirement for Role-Based Access Control (RBAC) in client
interface

Policy-Authorization-Role represents a role assigned to a Policy-User
that determines whether a user or has read-write access, read-only
access, or no access for certain resources. A User can be mapped to
a Policy-Authorization-Role using an internal or external identity
provider or mapped statically.

4.4. Requirement to protect client interface from attacks

There Must

The interface must be protections from attacks, malicious or
otherwise, from clients or a client impersonator. Potential attacks
could come from
a botnet or a host or Botnets, hosts infected with virus or some
unauthorized entity. It is recommended that security controller Security Controller use
a dedicated IP interface for client-facing Client-Facing communications and those
communications should be carried over an isolated out-of-band
network. In addition, it is recommended that traffic between clients
and security controllers Security controller be encrypted. Furthermore, some
straightforward traffic/session control mechanisms (i.e., Rate-limit,
ACL, White/Black list) can be employed on the security controller Security Controller to
defend against DDoS flooding attacks.

4.5. Requirement to protect client interface from misconfiguration

There Must must be protections from mis-configured clients. System and
policy validations should be implemented to detect this. Validation
may be based on a set of default parameters or custom tuned
thresholds such as the number of policy changes submitted, number of
objects requested in a given time interval, etc.

4.6. Requirement to manage policy lifecycle with diverse needs

In order to provide more sophisticated security framework, there
should be a mechanism to express so that a policy becomes dynamically
active/enforced active/
enforced or inactive based on either security administrator's Security Admin's manual intervention or an
some external event.

One example of dynamic policy management is when the security
administrator pre-configures Security Admin pre-
configures all the security policies, but the policies get activated
or deactivated based on dynamic threats. Basically, a threat event
may activate certain inactive policies, and once a new event
indicates that the threat has gone away, the policies become inactive
again.

There are following ways for dynamically activating policies:

o The policy may be dynamically activated by the I2NSF client Security Admin or
associated management entity, and dynamically communicated over the
I2NSF client-facing interface to the controller to program I2NSF
functions using the I2NSF NSF-facing interface entity

o The policy may be pulled dynamically activated by the controller Security Controller upon
detecting an external event over the or an event from I2NSF monitoring
interface

o The policy may be statically pushed to the controller and
dynamically programmed on the NSFs upon potentially detecting another
event

o The policy can be programmed in the NSF, and statically configured but activated or
deactivated upon policy attributes, like time or admin enforced.

The client-facing such as timing calendar

Client-Facing interface should support the following policy
attributes for policy enforcement:

Admin-Enforced: The A policy, once configured, remains active/enforced
until removed by the security administrator. Security Admin.

Time-Enforced: The A policy configuration specifies the time profile
that determines when the policy is to be activated/enforced.
Otherwise, it is de-activated.

Event-Enforced: The A policy configuration specifies the event profile
that determines when the policy is to be activated/enforced. It
also specifies the duration attribute of that policy once
activated based on event. For instance, if the policy is
activated upon detecting an application flow, the policy could be
de-activated when the corresponding session is closed or the flow
becomes inactive for certain time.

A policy could be a composite policy, that is composed of many rules,
and subject to updates and modification. For the policy maintenance,
enforcement, and auditability audit-ability purposes, it becomes important to name
and version the policies. Security Policy. Thus, the policy definition SHALL
support policy naming and versioning. In addition, the i2NSF client-facing Client-
Facing interface SHALL support the activation, deactivation,
programmability, and deletion of policies based on name and version.
In addition, it should support reporting on the operational state of
policies by name and version. For instance, a client may probe the controller
about the current policies
Security Controller whether a Security Policy is enforced for a
tenant and/or a sub-tenant (organization) for auditability audit-ability or
verification purposes.

4.7. Requirement to define dynamic policy Endpoint group

When the security administrator Security Admin configures a security policy, Security Policy, it may have
requirement to apply this policy to certain subsets of the network.
The subsets may be identified based on criteria such as
users, devices, Users,
Devices, and applications. Applications. We refer to such a subset of the network
as a "Policy Endpoint Group".

One of the biggest challenges for a security administrator Security Admin is how to make
sure that security policies a Security Policy remain effective while constant changes
are happening to the "Policy Endpoint Group" for various reasons
(e.g., organizational, network and application changes). If a policy
is created based on static information such as user names,
application, or network subnets; then every time this static
information change, policies need to be updated. For example, if a
policy is created that allows access to an application only from the
group of Human Resource users (the HR-users (HR-users group), then each time the HR- users
HR-users group changes, the policy needs to be updated.

We call these dynamic Policy Endpoint Groups "Meta-data Driven
Groups". The meta-data is a tag associated with endpoint information
such as users, applications, and devices. User, Application, or Device. The mapping from meta-data to
dynamic content could come either from a standards-based or proprietary
tools. The security controller Security Controller could use any available mechanisms to
derive this mapping and to make automatic updates to
the policy content
if the mapping information changes. The system SHOULD allow for
multiple, or sets of tags to be applied to a single network object.

The client-facing

Client-Facing policy interface must support endpoint groups for
user-construct based policy management.
expressing a Security Policy. The following meta-data driven groups
MAY be used for configuring security polices:

User-Group: This group identifies a set of users based on a tag or
on static information. The tag to identify user is dynamically
derived from systems such as Active Directory or LDAP. For
example, an operator organization may have different user-groups, User-groups, such as HR-
users,
HR-users, Finance-users, Engineering-users, to classify a set of
users in each department.

Device-Group: This group identifies a set of devices based on a tag
or on static information. The tag to identify device is
dynamically derived from systems such as configuration mannagement management
database (CMDB). For example, a security administrator Security Admin may want to
classify all machines running one a particular operating system into
one group and machines running another a different operating system into
another group.

Application-Group: This group identifies a set of applications based
on a tag or on static information. The tag to identify
application is dynamically derived from systems such as CMDB. For
example, a security administrator Security Admin may want to classify all applications
running in the Legal department into one group and all
applications running under a specific operating system in the HR department into another group. In
some cases, the application can semantically associated with a VM
or a device. However, in other cases, the application may need to
be associated with a set of identifiers (e.g., transport numbers,
signature in the application packet payload) that identify the
application in the corresponding packets. The mapping of
application names/tags to signatures in the associated application
packets should be defined and communicated to the NSF. The client-facing
Client-Facing Interface shall support the communication of this
information.

Location-Group: This group identifies a set of location tags. Tag
may correspond 1:1 to location. The tag to identify location is
either statically defined or dynamically derived from systems such
as CMDB. For example, a security administrator Security Admin may want to classify all
sites/locations in a geographic region as one group.

4.8. Requirement to express rich set of policy rules

The security policy rules can be as simple as specifying a match for
the user or application specified through "Policy Endpoint Group" and
take one of the "Policy Actions" or more complicated rules that
specify how two different "Policy Endpoint Groups" interact with each
other. The client-facing Client-Facing interface must support mechanisms to allow
the following rule matches.

Policy Endpoint Groups: The rule must allow a way to match either a
single or a member of a list of "Policy Endpoint Groups".

There must be a way to express a match between two "Policy Endpoint
Groups" so that a policy can be effective for communication between
two groups.

Direction: The rule must allow a way to express whether the security
administrator Security
Admin wants to match the "Policy Endpoint Group" as the source or
destination. The default should be to match both directions, if
the direction rule is not specified in the policy.

Threats: The rule should allow the security administrator to express
a match for threats that come either in the form of feeds (such as
botnet
Botnet feeds, GeoIP feeds, URL feeds, or feeds from a SIEM) or
speciality security appliances. Threats could be identified by
Tags/names in policy rules. The tag is a label of one or more
event types that may be detected by a threat detection system.

The threat could be from malware and this requires a way to match for
virus signatures or file hashes.

4.9. Requirement to express rich set of policy actions

The security administrator

Security Admin must be able to configure a variety of actions within
a security policy. Typically, security policy specifies a simple
action of "deny" or "permit" if a particular condition is matched.
Although this may be enough for most of the simple policies, the
I2NSF client-facing Client-Facing interface must also provide a more comprehensive
set of actions so that the interface can be used effectively across
various security functions.

Policy action MUST be extensible so that additional policy action
specifications can easily be added.

The following list of actions SHALL be supported:

Permit: This action means continue processing the next rule or allow
the packet to pass if this is the last rule. This is often a
default action.

Deny: This action means stop further packet processing and drop the
packet.

Drop connection: This action means stop further packet processing,
drop the packet, and drop connection (for example, by sending a
TCP reset).

Log: This action means create a log entry whenever a rule is
matched.

Authenticate connection: This action means that whenever a new
connection is established it should be authenticated.

Quarantine/Redirect: This action may be relevant for event driven
policy where certain events would activate a configured policy
that quarantines or redirects certain packets or flows. The
redirect action must specify whether the packet is to be tunneled
and in that case specify the tunnel or encapsulation method and
destination identifier.

Netflow: This action creates a Netflow record; Need to define
Netflow server or local file and version of Netflow.

Count: This action counts the packets that meet the rule condition.

Encrypt: This action encrypts the packets on an identified flow.
The flow could be over an Ipsec IPSEC tunnel, or TLS session for
instance.

Decrypt: This action decrypts the packets on an identified flow.
The flow could be over an Ipsec IPSEC tunnel, or TLS session for
instance.

Throttle: This action defines shaping a flow or a group of flows
that match the rule condition to a designated traffic profile.

Mark: This action defines traffic that matches the rule condition by
a designated DSCP value and/or VLAN 802.1p Tag value.

Instantiate-NSF: This action instantiates an NSF with a predefined
profile. An NSF can be any of the FW, LB, IPS, IDS, honeypot, or
VPN, etc.

WAN-Accelerate: This action optimizes packet delivery using a set of
predefined packet optimization methods.

Load-Balance: This action load balances connections based on
predefined LB schemes or profiles.

The policy actions should support combination of terminating actions
and non-terminating actions. For example, Syslog and then Permit;
Count and then Redirect.

Policy actions SHALL support any L2, L3, L4-L7 policy actions.

4.10. Requirement to express policy in a generic model

Client-facing

Client-Facing interface SHALL provide a generic metadata model that
defines once and then be used by appropriate model elements any
times, regardless of where they are located in the class hierarchy,
as necessary.

Client-facing

Client-Facing interface SHALL provide a generic context model that
enables the context of an entity, and its surrounding environment, to
be measured, calculated, and/or inferred.

Client-facing

Client-Facing interface SHALL provide a generic policy model that
enables context-aware policy rules to be defined to change the
configuration and monitoring of resources and services as context
changes.

Client-facing

Client-Facing interface SHALL provide the ability to apply policy or
multiple sets of policies to any given object. Policy application
process SHALL allow for nesting capabilities of given policies or set
of policies. For example, an object or any given set of objects
could have application team applying certain set of policy rules,
while network team would apply different set of their policy rules.
Lastly, security team would have an ability to apply its set of
policy rules, being the last policy to be evaluated against.

4.11. Requirement to detect and correct policy conflicts

Client-facing

Client-Facing interface SHALL be able to detect policy "conflicts",
and SHALL specify methods on how to resolve these "conflicts"

For example: two clients issues conflicting set of security policies
to be applied to the same Policy Endpoint Group.

4.12. Requirement for backward compatibility

It MUST be possible to add new capabilities to client-facing Client-Facing
interface in a backward compatible fashion.

4.13. Requirement for Third-Party integration

The security policies in the security administrator's a network may require the use of specialty
devices such as honeypots, behavioral analytics, or SIEM in the
network, and may also involve threat feeds,
virus feeds,virus signatures, and
malicious file hashes as part of comprehensive security policies.

The client-facing Client-Facing interface must allow the security administrator allow Security Admin to configure
these threat sources and any other information to provide integration
and fold this into policy management.

4.14. Requirement to collect telemetry data

One of the most important aspect of security is to have visibility
into the networks. As threats become more sophisticated, the
security administrator Security
Admin must be able to gather different types of telemetry data from
various devices in the network. The collected data could simply be
logged or sent to security analysis engines for behavioral analysis,
policy violations, and for threat detection.

The client-facing Client-Facing interface MUST allow the security administrator Security Admin to collect
various kinds of data from NSFs. The data source could be syslog,
flow records, policy violation records, and other available data.

Detailed client-facing Client-Facing interface telemetry data should be available
between clients and security controllers. Security Controller. Clients should be able to
subscribe and receive these telemetry data.

client should be able to receive notifications when a policy is
dynamically updated.

5. Operational Requirements for the Client-Facing Interface

5.1. API Versioning

The client-facing

Client-Facing interface must support a version number for each
RESTful API. This is very important because the client application
and the controller application may most likely come from different vendors. Even
if the vendor is same, it is hard to imagine that two different
applications would be released in lock step.

Without API versioning, it is hard to debug and figure out issues if
an application breaks. Although API versioning does not guarantee
that applications will always work, it helps in debugging if the
problem is caused by an API mismatch.

5.2. API Extensiblity

Abstraction and standardization of the client-facing Client-Facing interface is of
tremendous value to security administrators Security Admin as it gives them the flexibility
of deploying any vendor's NSF without needing need to redefine their policies
if or change the client interface. However this might
also look like as an obstacle to innovation. when a NSF is changed.

If a vendor comes up with new feature or functionality that can't be
expressed through the currently defined client-facing Client-Facing interface,
there must be a way to extend existing APIs or to create a new API
that is relevant for that NSF vendor only.

5.3. APIs and Data Model Transport

The APIs for client interface must be derived from the YANG based
data model. The YANG data model for client interface must capture
all the requirements as defined in this document to express a
security policy. The interface between a client and controller must
be reliable to ensure robust policy enforcement. One such transport
mechanism is RESTCONF that uses HTTP operations to provide necessary
CRUD operations for YANG data objects, but any other mechanism can be
used.

5.4. Notification

The client-facing

Client-Facing interface must allow the security administrator Security Admin to collect various
alarms and events from the NSF in the network. The events and alarms
may be either related to security policy
enforcement itself or related to NSF operation.
where the policy is implemented. The events and alarms could also be
used as a an input to the security policy for autonomous handling. handling as
specified in a given security policy.

5.5. Affinity

The client-facing

Client-Facing interface must allow the security administrator Security Admin to pass any
additional metadata that a user may want to provide for a security
policy e.g. certain security policy needs to be applied implemented only on linux machine or windows machine or that a security policy must be
applied on the device
very highly secure NSF with Trusted Platform Module (TPM) chip. A
user may require Security Controller not to share the NSF with other
tenant, this must be expressed through the interface API.

5.6. Test Interface

The client-facing

Client-Facing interface must allow the security administrator the Security Admin ability to test the a
security policies policy before the policies are
actually applied it is enforced e.g. a user may want to verify if a
whether the policy creates any potential conflicts with the existing
policies or whether a certain
policy can be implemented. if there are even resources to enforce the policy. The
test interface provides policy would provide such
capabilities a capability without actually applying
the policies.

6. Security Considerations

Client-Facing interface to Security controller must be protected to
ensure that entire security posture is not compromised. This draft
mandates that interface must have proper authentication and
authorization with Role Based Access Controls to address multi-
tenancy requirement. The draft does not specify a particular
mechanism as different organization may have different needs based on
their deployment. This has been discussed extensively in this draft.

Authentication and authorization alone may not be sufficient for
Client-Facing interface; the interface API must be validated for
proper inputs to guard against attacks. The type of checks and
verification may be specific to each interface API, but a careful
consideration must be made to ensure that Security Controller is not
compromised.

7. IANA Considerations

This document requires no IANA actions. RFC Editor: Please remove
this section before publication.

8. Acknowledgements

The authors would like to thank Adrian Farrel, Linda Dunbar and Diego
R.Lopez from IETF I2NSF WG for helpful discussions and advice.

The authors would also like to thank Kunal Modasiya, Prakash T.
Sehsadri and Srinivas Nimmagadda from Juniper networks for helpful
discussions.

9. Normative References

[I-D.ietf-i2nsf-problem-and-use-cases]
Hares, S., Dunbar, L., Lopez, D., Zarny, M., and C. Jacquenet, C., Kumar, R.,
and J. Jeong, "I2NSF Problem Statement and Use cases", draft-
ietf-i2nsf-problem-and-use-cases-02
draft-ietf-i2nsf-problem-and-use-cases-15 (work in
progress),
October 2016. April 2017.

Authors' Addresses

Rakesh Kumar
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
US

Email: rkkumar@juniper.net

Anil Lohiya
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
US

Email: alohiya@juniper.net
Dave Qi
Bloomberg
731 Lexington Avenue
New York, NY 10022
US

Email: DQI@bloomberg.net

Nabil Bitar
Nokia
755 Ravendale Drive
Mountain View, CA 94043
US

Email: nabil.bitar@nokia.com

Senad Palislamovic
Nokia
755 Ravendale Drive
Mountain View, CA 94043
US

Email: senad.palislamovic@nokia.com

Liang Xia
Huawei
101 Software Avenue
Nanjing, Jiangsu 210012
China

Email: Frank.Xialiang@huawei.com