I2NSF Working Group R. Kumar
Internet-Draft A. Lohiya
Intended status: Informational Juniper Networks
Expires: May 1, 2017 D. Qi
Bloomberg
N. Bitar
S. Palislamovic
Nokia
L. Xia
Huawei
October 28, 2016
Requirements for Client-Facing Interface to Security Controller
draft-kumar-i2nsf-client-facing-interface-req-02
Abstract
This document captures the requirements for the client-facing
interface to the security controller. The interfaces are based on
user constructs understood by a security admin instead of a vendor or
a device specific mechanism requiring deep knowledge of individual
products and features. This document identifies the requirements
needed to enforce the user-construct oriented policies onto network
security functions (NSFs) irrespective of how those functions are
realized. The function may be physical or virtual in nature and may
be implemented in networking or dedicated appliances.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 1, 2017.
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Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in this Document . . . . . . . . . . . . . . 4
3. Guiding principles for definition of Client-Facing Interfaces 5
3.1. User-construct based modeling . . . . . . . . . . . . . . 5
3.2. Basic rules for client 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
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
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
5.3. APIs and Data Model Transport . . . . . . . . . . . . . . 20
5.4. Notification . . . . . . . . . . . . . . . . . . . . . . 20
5.5. Affinity . . . . . . . . . . . . . . . . . . . . . . . . 20
5.6. Test Interface . . . . . . . . . . . . . . . . . . . . . 20
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6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
8. 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. This has been the biggest challenge for both service
providers and enterprises, henceforth named as security administrator
in this document. The challenge is amplified due to virtualization
with security appliances in physical and virtual form factor from a
wide variety of vendors; each vendor have their own proprietary
interfaces to express security policies on their devices.
Even if a security administrator deploys a single vendor solution
with one or more security appliances across its entire network, it is
still difficult to manage security policies due to complexity of
security features, and difficulty in mapping business requirement to
vendor specific configuration. The security administrator may use
either vendor provided CLIs or management system with some
abstraction 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 rely on a single vendor because
one vendor may not be able to keep up with their security
requirements or specific deployment model.
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 vendor due to regulatory requirement or
organizational policy.
o If and when security administrator migrates from one vendor to
another, it is almost impossible to migrate security policies from
one vendor solution to another without complex manual workflows.
o Security administrators deploy various security functions in
virtual or physical forms to attain the flexibility, elasticity,
performance, 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 choose various devices or network
services (such as routers, switches, firewall devices, and
overlay-networks) as enforcement points for security policies.
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This my be for reason (such as network design simplicity, cost,
most-effective place, scale and performance).
In order to ease the deployment of security policies across different
vendors and devices, the Interface to Network Security Functions
(I2NSF) working group in the IETF is defining a client-facing
interface from the security controller to clients [I-D. 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. Using these
interfaces, it would become possible to write different kinds of
application (e.g. GUI portal, template engine, etc.) to control the
implementation of security policies on security functional elements,
though how these applications are implemente are completely out of
the scope of the I2NSF working group, which is only focused on the
interfaces.
This document captures the requirements for the client-facing
interface that can be easily used by security administrators without
knowledge of specific security devices or features. We refer to this
as "user-construct" based interfaces. To further clarify, in the
scope of this document, the "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 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
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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 for definition of Client-Facing Interfaces
The "Client-Facing Interface" ensures that a security administrator
can deploy any device from any vendor and still be able to use a
consistent interface. In essence, this interface gives ability to
security admins to express their security policies independent of how
security functions are implemented in their deployment. Henceforth,
in this document, we use "security policy management interface"
interchangeably when we refer to the client-facing interface.
3.1. User-construct based modeling
Traditionally, security policies have been expressed using
proprietary interfaces. These interface are defined by a vendor
either based on CLI or a GUI system; but more often these interfaces
are built using vendor specific networking construct such IP address,
protocol and application constructs with L4-L7 information. This
requires security operator to translate their oragnzational business
objectives into actionable security policies on the device using
vendor specific configuration. But, this alone is not sufficient to
render policies in the network as operator also need to identify the
device in the network topology where a policy need to be enforced in
a complex environment with potenial multiple policy enforcement
points.
The User-construct based framework defines constructs such as user-
group, application-group, device-group and location-group. The
security admin would use these constructs to express a security
policy instead of proprietary vendor specific constructs. The policy
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defined in such a manner is referred to user-construct based policies
in this draft. The idea is to enable security admin to use
constructs they understand best in expressing security policies;
which simplify their tasks and help avoiding human errors in complex
security provisioning.
3.2. Basic rules for client interface definition
The basic rules in defining the client-facing interfaces are as
follows:
o Not depending on particular network topology or the actual NSF
location in the network
o Not requiring the exact knowledge of the concrete features and
capabilities supported in the deployed NSFsa€
o Independent of the nature of the function that will apply the
expressed policies be it stateful firewall,IDP, IDS, Router,
Switch
o Declarative/Descriptive model instead of Imperative/Prescriptive
model - What security policies need to be enforced (declarative)
instead of how they would be actually implemented (imperative)
o Not depending on any specific vendor implementation or form-factor
(physical, virtual) of the NSF
o Not depending on how a NSF becomes operational - Network
connectivity and other hosting requirements.
o Not depending 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 a user will define a high level policy. These rules
do not apply to the lower layers e.g. 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.
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3.3. Deployment Models for Implementing Security Policies
Traditionally, medium and larger operators deploy management systems
to manage their 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.
There are two different deployment models in which the client-facing
interface referred to in this document could be implemented. These
models have no direct impact on the client-facing interface, but
illustrate the overall security policy and management framework and
where the various processing functions reside. These models are:
a. Management without an explicit management system for control of
devices and NSFs. In this deployment, the security controller
acts as a NSF policy management system that takes information
passed over the client security policy interface and translates
into data on the I2NSF NSF-facing interface. The I2NSF
interfaces are implemented by security device/function 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.
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RESTful API
SUPA or I2NSF Policy Management
^
|
Client-facing Interface |
(Independent of individual |
NSFs, devices,and vendors)|
|
------------------------------
| |
| Security Controller |
| |
------------------------------
| ^
| I2NSF |
NSF Interface | NSF-facing |
(Specific to NSFs) | Interface |
..............................
| |
v |
------------- -------------
| 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 with an explicit management system for control of
devices and NSFs. This model is similar to the model above
except that security controller interacts with a dedicated
management system which could either proxy I2NSF NSF-facing
interfaces or could provide a layer where security devices or
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NSFs do not support an I2NSF agent to process I2NSF NSF-facing
interfaces. This deployment model is shown in Figure 2.
RESTful API
SUPA or I2NSF Policy Management
^
|
Client-facing Interface |
(Independent of individual |
NSFs,devices,and vendors) |
|
------------------------------
| |
| Security Controller |
| |
------------------------------
| ^
| I2NSF |
NSF Interface | NSF-facing |
(Specific to NSFs) | Interface |
..............................
| |
v |
------------------------------
| |
| I2NSF Proxy Agent / |
| Management System |
| |
------------------------------
| ^
| Proprietary |
| Functional |
| Interface |
..............................
| |
v |
------------- -------------
| |---| |
| NSF | | NSF |
NSFs | | | |
(virtual -------------\ /-------------
and | \ / |
physical) | X |
| / \ |
-------------/ \-------------
| |---| |
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| 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 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 for defining I2NSF client-facing
interface, the security policies and the client-facing interface
shall be defined from a user/client perspective and abstracted away
from the type of NSF, NSF specific implementation, controller
implementation, NSF topology, NSF interfaces, controller NSF-facing
interfaces. Thus, the security policy definition shall be
declarative, expressing the user construct, and driven by how
security administrators view security policies from the definition,
communication and deployment perspective.
The 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 for the client-facing are 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
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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, 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 may have
internal tenants and would like to have a framework wherein each
tenant manages its own security policies with isolation from other
tenants.
An operator may be a cloud service provider with multi-tenant
deployments, 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 may have multiple departments or organizations that
need to manage their own security rules.
Some key concepts are listed below and used throughout the document
hereafter:
Policy-Tenant: An entity that owns and manages the security 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.
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4.2. Requirement for Authentication and Authorization of client
interface
Security administrators MUST authenticate to and be authorized by the
security controller before they are able to issue control commands
and any policy data exchange commences.
There must be methods defined for the Policy-Administrator to be
authenticated and authorized to use the security controller. There
are several authentication methods available such as OAuth, XAuth and
X.509 certificate based. The authentication scheme between Policy-
Administrator and security controller may also be mutual instead of
one-way. Any specific method may be determined based on
organizational and deployment needs and outside the scope of I2NSF.
In addition, there must be a method to authorize the Policy-
Administrator for performing certain action. It should be noted
that, depending on the deployment model, Policy-Administrator
authentication and authorization to perform actions communicated to
the controller could be performed as part of a portal or another
system prior to communication the action to the controller.
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 be protections from attacks, malicious or otherwise, from
clients or a client impersonator. Potential attacks could come from
a botnet or a host or hosts infected with virus or some unauthorized
entity. It is recommended that security controller use a dedicated
IP interface for 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 be encrypted. Furthermore, some
straightforward traffic/session control mechanisms (i.e., Rate-limit,
ACL, White/Black list) can be employed on the security controller to
defend against DDoS flooding attacks.
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4.5. Requirement to protect client interface from misconfiguration
There 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 that a policy becomes dynamically
active/enforced or inactive based on either security administrator's
manual intervention or an event.
One example of dynamic policy management is when the security
administrator 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 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
o The policy may be pulled dynamically by the controller upon
detecting an event over the 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 activated or
deactivated upon policy attributes, like time or admin enforced.
The client-facing interface should support the following policy
attributes for policy enforcement:
Admin-Enforced: The policy, once configured, remains active/enforced
until removed by the security administrator.
Time-Enforced: The policy configuration specifies the time profile
that determines when policy is activated/enforced. Otherwise, it
is de-activated.
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Event-Enforced: The policy configuration specifies the event profile
that determines when policy is 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 purposes, it becomes important to name
and version the policies. Thus, the policy definition SHALL support
policy naming and versioning. In addition, the i2NSF 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 state of policies by
name and version. For instance, a client may probe the controller
about the current policies enforced for a tenant and/or a sub-tenant
(organization) for auditability or verification purposes.
4.7. Requirement to define dynamic policy Endpoint group
When the security administrator configures a 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, and applications. We refer to such a subset of the
network as a "Policy Endpoint Group".
One of the biggest challenges for a security administrator is how to
make sure that security policies 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 group), then each time
the 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. The mapping from meta-data
to dynamic content could come either from standards-based or
proprietary tools. The 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.
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The client-facing policy interface must support endpoint groups for
user-construct based policy management. 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 may have different user-groups, such as 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
database (CMDB). For example, a security administrator may want
to classify all machines running one operating system into one
group and machines running another 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 may want to classify all
applications running in the Legal department into one group and
all applications running under a specific operating system 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 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 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
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other. The 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 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 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 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 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.
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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 tunnel, or TLS session for
instance.
Decrypt: This action decrypts the packets on an identified flow.
The flow could be over an 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.
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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 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 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 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 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 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
interface in a backward compatible fashion.
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4.13. Requirement for Third-Party integration
The security policies in the security administrator's 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 signatures, and malicious file hashes as part of comprehensive
security policies.
The client-facing interface must allow the security administrator 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 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 interface MUST allow the security administrator 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 interface telemetry data should be available
between clients and security controllers. 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 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
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.
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5.2. API Extensiblity
Abstraction and standardization of the client-facing interface is of
tremendous value to security administrators as it gives them the
flexibility of deploying any vendor's NSF without needing to redefine
their policies or change the client interface. However this might
also look like as an obstacle to innovation.
If a vendor comes up with new feature or functionality that can't be
expressed through the currently defined 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 interface must allow the security administrator to
collect various alarms and events from the NSF in the network. The
events and alarms may be either related to security policy
enforcement or NSF operation. The events and alarms could also be
used as a input to the security policy for autonomous handling.
5.5. Affinity
The client-facing interface must allow the security administrator 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 only
on linux machine or windows machine or that a security policy must be
applied on the device with Trusted Platform Module chip.
5.6. Test Interface
The client-facing interface must allow the security administrator the
ability to test the security policies before the policies are
actually applied e.g. a user may want to verify if a policy creates
potential conflicts with the existing policies or whether a certain
policy can be implemented. The test interface provides such
capabilities without actually applying the policies.
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6. IANA Considerations
This document requires no IANA actions. RFC Editor: Please remove
this section before publication.
7. 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.
8. Normative References
[I-D.ietf-i2nsf-problem-and-use-cases]
Hares, S., Dunbar, L., Lopez, D., Zarny, M., and C.
Jacquenet, "I2NSF Problem Statement and Use cases", draft-
ietf-i2nsf-problem-and-use-cases-02 (work in progress),
October 2016.
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
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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
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