SMART M McFadden
Internet Draft internet policy advisors ltd
Intended status: Informational July 8, 2019
Expires: January 8, 2020
Endpoint Taxonomy for CLESS
draft-mcfadden-smart-endpoint-taxonomy-for-cless-00.txt
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Abstract
A separate document [I-D:draft-taddei-smart-cless-introduction]
(CLESS) attempts to establish the capabilities and limitations of
endpoint-only security solutions and explore potential alternative
approaches. That document discusses endpoints in general terms. It
has been suggested that there are classes of endpoints that have
different characteristics. Those classes may have completely
different threat landscapes and the endpoints may have completely
different security capabilities. In support of the work on CLESS,
this document provides a taxonomy of endpoints that is intended to
provide a foundation for further work on CLESS and research on
approaches to providing endpoint security alternatives in a diverse
group of settings.
Table of Contents
1. Introduction...................................................3
2. Conventions used in this document..............................4
3. Problem Statement..............................................4
4. The Endpoint in CLESS..........................................4
5. Taxonomy.......................................................5
5.1. Traditional and Enterprise Computing Equipment [TECE].....6
5.1.1. Description..........................................6
5.1.2. Endpoint characteristics.............................6
5.2. Personal Computing Equipment..............................6
5.2.1. Description..........................................6
5.2.2. Endpoint characteristics.............................7
5.3. Human Interface Devices...................................8
5.3.1. Endpoint description.................................8
5.3.2. Endpoint characteristics.............................8
5.4. Human Sensor Devices......................................8
5.4.1. Endpoint characteristics.............................8
5.5. Non-human Sensor Devices..................................9
5.5.1. Endpoint Description.................................9
5.5.2. Endpoint characteristics.............................9
5.6. Peripheral Computing Equipment and Embedded Endpoints....10
5.6.1. Endpoint Description................................10
5.6.2. Endpoint characteristics............................10
5.7. Internet Infrastructure Devices..........................11
5.7.1. Endpoint Description................................11
5.7.2. Endpoint characteristics............................11
5.8. Application Layer Endpoints..............................12
5.8.1. Description.........................................12
5.8.2. Endpoint Characteristics............................12
6. Security Considerations.......................................12
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7. IANA Considerations...........................................12
8. References....................................................12
8.1. Normative References.....................................12
8.2. Informative References...................................13
9. Acknowledgments...............................................13
Appendix A. Document History.....................................14
1. Introduction
A document entitled "Capabilities and Limitations of an Endpoint-only
Security Solution (CLESS) [I-D. draft-taddei-smart-cless-
introduction-00] attempts to initiate research into the limits of
endpoint-only security solutions. The document identifies changes in
technology, economics and protocol development that have impacted the
provision of endpoint security.
The CLESS introduction focuses on endpoints that are User Equipment
rather than hosts. Even so, this encompasses an enormous variety of
possible endpoints. CLESS takes a unified view of endpoints - seeing
them all as one type.
However, it seems reasonable to suggest that, in the huge variety of
types of endpoints, there are categories of similarity. These
categories are important because categories of endpoint devices may
share particular advantages or limitations for endpoint security.
While CLESS provides a clear model for understanding some of the
limitations of endpoint security in today's networks, it is very
likely that more specificity is needed.
This draft attempts to suggest a Taxonomy of Endpoints as a
foundation for further work on CLESS. The goal is to identify
classes of endpoints with similar characteristics. Those
characteristics may lead to the discovery that the devices in a
particular category share similar characteristics for endpoint
security.
It is essential to understand that this taxonomy is intended as a
foundation for work on CLESS and is not an all-purpose guide to the
enormous breadth of devices that are or could be endpoints on public
or private networks. Others have attempted to provide classifications
for end devices, but they are not focused on the issues related to
endpoint security. In addition, most are almost immediately out-of-
date when published.
This document takes a different approach: the taxonomy here is
intended to support the work of CLESS and provide a classification
system that may make it possible to group endpoints in related
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categories for the purpose of discussing their security
characteristics. While a general-purpose taxonomy of Internet
endpoints might be useful in a variety of settings, it is not the
intended goal of this document.
In addition, this document does not attempt to assess and document
the endpoint security characteristics of each part of the taxonomy.
The work of identifying advantages and limitations of specific
classes of endpoints is envisioned as future work on CLESS.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Problem Statement
CLESS attempts to provide an analysis of the current state of the
provision of endpoint security. It does that by providing a
provisional definition of an endpoint and then examining the
advantages and limitations of providing security at that endpoint.
The original approach to CLESS divides the universe of endpoints into
User Equipment (UE) and hosts - and then focuses entirely on User
Equipment.
User Equipment encompasses a very broad set of endpoints. It may be
possible to provide a stronger set of device type groupings.
Endpoints in the same groups may share security chrematistics that
are particular to that group. The fundamental question is: can a
taxonomy of endpoint devices be created that allows for grouping of
endpoints that have similar security characteristics?
If it is possible to answer that question in the affirmative, then
research can be done on the security characteristics of each category
and influence the development of protocols that have the greatest
impact for those type of devices.
4. The Endpoint in CLESS
CLESS simplifies the representation of an endpoint by making the
following generalization:
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+------------------------------------------------+
| |
| Application |
| |
|------------------------------------------------|
| |
| OS / Execution Environment |
| |
|------------------------------------------------|
| |
| Hardware |
| |
+------------------------------------------------+
Figure 1 Endpoint Generalization in CLESS
This simplification means that there are many combinations of
hardware, operating systems, execution environments and applications.
It also means that any of these three layers can be an endpoint for
the purposes of a discussion of endpoint security.
CLESS suggests that we consider endpoints including those which have
a variety of power, computational, storage and network capacities. It
is possible that grouping devices with similar characteristics will
help in identifying categories of devices that share similar endpoint
security characteristics.
5. Taxonomy
Others have attempted to provide general-purpose taxonomy and device
classification guides (informative references to be provided in a
later draft version). In some settings automated detection and
classification of devices provides an essential step in providing
appropriate access control and security services.
General-purpose classification systems tend to ossify or become
enormously complex. Classification has come from commercial entities,
computer science organizations, the academic community and even
regional collections of cooperating national governments.
For the purposes of providing a taxonomy for CLESS, we limit the
discussion to a taxonomy for endpoints only. We divide endpoints into
nine different classes and then attempt to carefully describe the
characteristics of devices in each class.
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5.1. Traditional and Enterprise Computing Equipment [TECE]
5.1.1. Description
Traditional and Enterprise Computing Equipment is characterized by
its extremely high-capacity for transactional volume, storage and
shared user population. TECE forms the backbone of high-volume, high-
availability transactional computing and is provided in both physical
and virtualized forms.
Traditional computing endpoints are shared computing environments
characterized by centralized, shared computing. These endpoints are
often in large scale data centers. These endpoints are capable of
high-availability, substantial requirements for power and
environmental control. These endpoints are also characterized by very
complex operating systems and user environments.
5.1.2. Endpoint characteristics
o Cost - these endpoints are characterized by extremely high cost.
o Physical size - these are very large endpoints, not suitable or
intended for use by an individual.
o Network link characteristics - capable of supporting extremely
high bandwidth.
o User interface - very complex and shared among multiple
individuals.
o Processing power - extremely high processing capability.
o Physical power - requires substantial provision of electrical
power and environmental controls.
o Code complexity - Extremely high support for very complex code
including parallelism, multitaxking and multithreaded execution.
5.2. Personal Computing Equipment
5.2.1. Description
These are endpoints designed or intended to be used by an individual.
They can be delivered as fixed, portable or virtual instantiations of
the endpoint. It should be noted that virtual instantiations of
endpoints introduce complexities in defining the characteristics of
the endpoints. In each case, the device supports a mechanism for
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human-interface and has the capability for both local storage and
processing. The personal computing equipment class is also
characterized by relatively low cost and power requirements.
This class of endpoint is also characterized by the devices
supporting multiple purpose use. This class is divided into two sub-
classes: fixed and mobile endpoints. The mobile subclass is further
divided into four other subclasses: laptops, tablets, intelligent
phones, and ultraportable personal computing equipment.
Personal computing endpoints usually have at least one, and often
many, network links - often supporting a variety of network
connectivity technologies. These endpoints are also characterized by
having a human interface - either integral to the computing device
itself or supplied externally to the computing device.
5.2.2. Endpoint characteristics
o Cost - these endpoints have a huge range of costs, from extremely
inexpensive for simple "personal computer on a board" endpoints to
moderately expensive for specially configured laptop and fixed
devices.
o Physical size - the physical size of these devices range from
handheld to a small cabinet for fixed, desktop units.
o Network link characteristics - personal computing endpoints are
often characterized by supporting multiple connectivity
technologies.
o User interface - personal computing endpoints are characterized by
having user interfaces designed for an individual. The interface
varies from simple, text-based interaction to gesture, touch and
voice control.
o Processing power - these endpoints are characterized by a
significant range of processing power: from single CPU units to
endpoints that can support multiple concurrent processes.
o Physical power - personal computing endpoints are characterized by
using either traditional mains power or power supplied by a
battery.
o Code complexity - personal computing endpoints support complex
code and often parallel and multithreaded execution of code.
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5.3. Human Interface Devices
TBD.
5.3.1. Endpoint description
5.3.2. Endpoint characteristics
o Cost
o Physical size
o Network link characteristics
o User interface
o Processing power
o Physical power
o Code complexity
5.4. Human Sensor Devices
Description
These are endpoints whose primary purpose is to sense, store,
transmit or process information about a human being. These endpoints
are characterized as having use cases in health and wellness
monitoring, human performance enhancement, personalized medicine and
human safety.
The endpoints are characterized as sensor devices with the capacity
to sense, store and report on data collected on an individual. The
sensor may be multimodal. These endpoints are almost always
characterized by have a battery for power and having limited storage,
networking and processing capabilities.
5.4.1. Endpoint characteristics
o Cost - Human Sensor Endpoints can range in cost from very low (for
instance a heartbeat sensor) to quite expensive (a sensor built
into an implanted device).
o Physical size - human sensors are very small and almost always
portable.
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o Network link characteristics - human sensors usually have a single
network like technology available and are capable of very limited
bandwidth utilization on that link.
o User interface - human sensors have extremely limited, or no, user
interface.
o Processing power - human sensors are characterized by having
limited processing power - often incorporating only the ability to
collect store and forward sensed information.
o Physical power - human sensors are characterized by being powered
by internal batteries
o Code complexity - human sensors are not usually capable of running
complex code. Often, the capability of the endpoint is to simply
sense, store and forward data without reporting and analysis of
that data.
5.5. Non-human Sensor Devices
5.5.1. Endpoint Description
These endpoints are capable of sensing, storage, communication and
possibly some computation. They are characterized by having very low
bandwidth radios, a battery for power, sensor technology and a small
processor. Unlike in Section 5.4, these devices are not intended to
sense human-related information.
Compared with Human Sensors, non-human sensors often have a variety
of communications technologies available - for instance, self-
organizing into mesh networks.
5.5.2. Endpoint characteristics
o Cost - Non-human Sensor Endpoints can range in cost from very low
(for instance, a simple temperature sensor) to quite expensive (a
sensor built into an implanted device.
o Physical size - Non-human sensors are often small and almost
always portable.
o Network link characteristics - Non-human sensors usually have a
single network like technology available but the topology of those
network links can be highly varied. Quite often these devices are
capable of very limited bandwidth utilization on the link to which
they are attached.
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o User interface - non-human sensors have extremely limited, or no,
user interface.
o Processing power - non-human sensors are characterized by having
limited processing power - often incorporating only the ability to
collect store and forward sensed information. Some non-human
sensors have the capability to process stored data, but usually
this is limited.
o Physical power - -
o Code complexity - non-human sensors are not usually capable of
running complex code. Often, the capability of the endpoint is to
simply sense, store and forward data without reporting and
analysis of that data.
5.6. Peripheral Computing Equipment and Embedded Endpoints
5.6.1. Endpoint Description
These are endpoints that are "embedded" in devices that may have a
different primary function. An example is a network endpoint in a
printer that supports remote access, configuration and printing.
Another example is an endpoint in an appliance that has a different
primary function (for instance, a refrigerator).
In either case, the endpoint is characterized as being added to
another system, machine or peripheral.
These devices are characterized as being specialized for their
particular use case and function. Their specific characteristics
often depend upon the system, device or peripheral in which they are
being hosted. As an example, the embedded endpoint gets its physical
power and networking capabilities from the device in which it is
connected.
5.6.2. Endpoint characteristics
o Cost - almost never available as a standalone device - instead,
always embedded into the peripheral or system which is hosting it.
o Physical size - almost always very small - to be embedded into
some other system or device.
o Network link characteristics - dependent on network services
available from the host device and not always IP-based.
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o User interface - almost always provided by the "hosting" device.
Many embedded endpoints share a user interface with the
configuration and control tool for the underlying device.
o Processing power - usually limited and constrained by the use
case. Some embedded endpoints provide remote access to the
underlying resources provided by the processor.
o Physical power - generally supplied by the "host" system or
device.
o Code complexity - limited and almost always constrained by use
case.
5.7. Internet Infrastructure Devices
5.7.1. Endpoint Description
Internet Infrastructure endpoints are the physical components that
are used to deploy a network. There is a huge variety of these
devices, but they all share two common properties: they are building
blocks of the underlying network infrastructure and they also can be
endpoints of a network conversation.
But, there's an important question here. CLESS specifically rules out
network infrastructure in its discussion. Should the taxonomy for
CLESS incorporate endpoints that are part of the network
infrastructure? Said a different way: is network infrastructure out
of scope for CLESS?
5.7.2. Endpoint characteristics
TBD, depending on the answer to the question in section 5.7.1
o Cost
o Physical size
o Network link characteristics
o User interface
o Processing power
o Physical power
o Code complexity
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5.8. Application Layer Endpoints
5.8.1. Description
A significant trend in the contemporary public Internet is to have
applications act as completely independent agents - a situation where
the application itself provides the necessary infrastructure (for
instance, domain name resolution) to provide services. An example
would be a web browser that independently resolved domain names and
established secure communication channels independently.
The traffic between the application and the servers it uses might not
be available for analysis by security software. As a result,
application-based endpoints would have the characteristic of having
to provide security services (for instance, traffic security or
malware detection) for itself.
This type of endpoint also has the characteristic of potentially
having adverse impacts on other applications running on the same
platform. For example, if several applications are provisioning their
own infrastructure services, then those services are being duplicated
on that platform. For security related infrastructure there would be
no common, platform-wide approach to securing the applications or the
traffic generated between the application and external servers.
5.8.2. Endpoint Characteristics
TBD
6. Security Considerations
INFO (REMOVE): Every draft MUST have a Security Considerations
section.
TBD, descriptive
7. IANA Considerations
This document has no requirements or actions for IANA
8. References
8.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
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[2] Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, Internet Mail Consortium and
Demon Internet Ltd., November 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
Syntax Specifications: ABNF", RFC 2234, Internet Mail
Consortium and Demon Internet Ltd., November 1997.
8.2. Informative References
TBD
9. Acknowledgments
This document was prepared using 2-Word-v2.0.template.dot.
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Appendix A. Document History
[[ To be removed from the final document ]]
-0
Initial Internet Draft
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Authors' Addresses
Mark McFadden
Internet policy advisors ltd
Madison Wisconsin US
Email: mark@internetpolicyadvisors.com
Phone: <optional>
Email: <Your email address>
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