IS 6973

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IS 6973

• Secure Network Design
• Chapter One
• Network Security Axioms

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Axiom

• Ground rules
• Overarching design principles, considerations, or
  guidelines
• Thorough understanding of the axioms of network
  security will help you understand how to approach
  designing secure networks

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1 Network Security is a System

• It is not an IDS, nor a firewall, nor a VPN, nor
  any individual product or technology
• Instead, it is a collection of network-connected
  devices, technologies, and best practices that
  work in complementary ways to provide security to
  information assets.

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Network Security System

• Also referred to as Defense-in-Depth
• http//nsa1.www.conxion.com/support/guides/sd-1.pd
  f
• Need to focus on the technology, people, and
  operations. A change in any one of these areas
  could result in the need for change in the other
  areas

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Network Security System

• Implement complementary system elements to
  counter a given threat
• Deal with broad categories of attacks, rather
  than specific ones

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2 Business Priorities Must Come First

• Who wins when there is conflict between security
  concerns and business drivers?
• A secure system is worthless if the company
  cannot conduct its business
• Security designers must ensure that security
  implications and trade-offs are introduced as
  considerations in business planning
• Reach a balance between control, efficiency, and
  effectiveness

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3 Network Security Promotes Good Network Design

• Security should not be an add-on
• Rather, it should be considered from the
  beginning and built into the design
• If you have an existing insecure network design,
  logically divide the network into smaller modules
  and improve security one area at a time, starting
  with your area of greatest weakness

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4 Everything is a Target

• Networks are interdependent. This makes them
  both versatile and volatile
• You dont need to attack a target directly in
  order to severely impact a network
• You need to protect every system in your
  organization
• The attacker just needs to find the system not
  well protected

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5 Everything is a Weapon

• Once an attacker penetrates your system, he can
  use your technology, products, etc. to cause
  further damage

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6 Strive for Operational Simplicity

• Follow the KISS principle
• Security should be simple to deploy and
  straightforward to maintain
• Strive toward simplicity of planning, design,
  implementation, and operation

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7 Good Network Security is Predictable

• Your security system is only as good or as useful
  as you design and configure it to be
• Need to understand the role of each technology in
  your system, its limitations, and what other
  technologies guard against the same threat
• Primary goal Understand strengths and
  weaknesses of your security system so that when
  presented with a new threat, you can quickly
  decide whether your existing system will deal
  with the problem adequately (thus predictable)

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To Establish a Predictable Network

• Assure you understand the activity and events the
  system might experience, including attack vectors
• Consider how to mitigate these attacks
• Build in fault tolerance

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8 Avoid Security Through Obscurity

• Attempt to assure your design is indifferent to
  what other know about it.
• Keep system design and device selection
  confidential
• However, changing default ports (e.g., changing
  SMTP from port 25 to port 300) probably
  introduces more complexity, confusion, and time
  spent modifying applications than any inherent
  value of obscurity

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9 Confidentiality and Security are Not the Same

• Confidentiality protection of information to
  ensure that it is not disclosed to unauthorized
  audiences
• Security protection of systems, resources, and
  information from unintended and unauthorized
  access or misuse
• Security is a superset of confidentiality

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For Case

• Review each of these axioms.
• Does your proposed design consider these axioms?
  If not, how can you change your design?