Network security

Introduction

This session is based on the triad: confidentiality, integrity, availability:

• Confidentiality: prevent from leaking information without permission.
• Integrity: prevent from changing information without permission.
• Availability: make sure the valid users can access information and the system.

Moreover, 2 other security goals:

• Authenticity: ensure data comes from trust and legal source.
• Accountability: store logs, tracking.

Vulnerability, threat, risk

• Vulnerability: the weaknesses of system which
• Threat: new accident (or zero-day) can be harmful for all system or company.
• Risk: can loss or damage when threat exploit vulnerabilities.

Attack and coutermeasure

• Attack is the threat which can lead to unwanted violations of protection confidentiality or the consequences of the threat.
  • Active: attempt to change system resources, or work.
  • Passive: use information from system without affecting system resources.
• Coutermeasure: prevent or mitigate, recovery effects of attacks.

Some types of attacks

• Unauthorized disclosure:

  • Expose.
  • Interception.
  • Inference.
  • Intrusion.

• Deception:

  • Masquerade.
  • Falsification.
  • Repudiation.

• Disruption:

  • Incapacitation.
  • Corruption.
  • Obstruction.

• Usurpation:

  • Misappropriation.
  • Misuse.

Security design principles

• Economy of mechanism: keep the design as simple and small as possible.
• Fail-safe defaults: unless a subject is given explicit access to an object, it should be denied access to that object.
• Complete mediation: requiring access requests to be mediated every time, to avoid authority being circumvented through multiple requests.
• Open design: a system security shouldn’t rely on the secrecy of its implementation.
• Separation of privilege: requires multiple people to approve an action before it can be completed.
• Least privilege: a security architecture should be designed so that each entity is granted the minimum system resources and authorizations.
• Least common mechanism: mechanisms used to access resources should not be shared.
• Psychological acceptability: security mechanisms should not make the resource more difficult to access than if the security mechanisms were not present.
• Isolation: public access systems should be separated from critical resources (data, processes, etc.) to prevent disclosure or tampering.
• Encapsulation: the protected system can only access the data object of the system and these processes can only be invoked from a domain entry point.
• Modularity: the security mechanism must be generated as separate and protected modules and the security mechanism must be generated using the modular architecture.
• Layering: use of multiple, overlapping protection approaches addressing the people, technology, and operational aspects of information systems
• Least astonishment: should avoid surprising users (in an unpleasant way) at any cost.