Communications and Network Security Part 1

Kelly School of Business
Indiana University
Information Systems Graduate Programs

Part 1 – Introduction

Introduction

  • Network security is often described as the cornerstone of IT security
  • Security used to focus much on perimeter defense, but this is inadequate
  • As the ‘traditional’ network boundaries disappear, resiliency of the internal network becomes equally important
  • Tools without effective processes may be ineffective
  • Availability of a network is its key business value

Role of the Network in IT Security

  • Network as the target of attack
  • Network as an enabler or a channel of attack
  • Network as a channel is of greater concern and is more common
  • Network as a bastion of defense
  • The network is possibly the most valuable strategic asset in IT security

Network Security Objectives

  • Foundations (CIA/ACI)
  • Availability
  • Confidentiality
  • Integrity
  • Access control
  • Accountability
  • Auditability

Methodology of an Attack

Methodology of an Attack

The attack tree model (A defenders view of an attack)

Source: http://www.schneier.com/paper-attacktrees-ddj-ft.html

The Attackers Methodology

  • Target Acquisition
  • Target Analysis
  • Target Access
  • Target Appropriation
  • Sustain Control

Proactive Defense

Proactive Defense

Source: Official (ISC)2 Guide to the CISSP CBK, Fourth Edition ISC2 Press

Defense in Depth

Defense in Depth

Source: Official (ISC)2 Guide to the CISSP CBK, Fourth Edition ISC2 Press

Network Architecture

  • Security Perimeter
  • First line of protection; generally includes firewalls, proxies, and IDS
  • Network Partitioning
  • Segmenting networks into isolated domains of trust
  • Dual-Homed Hosts
  • Have two NICs, each on a separate Network Partitioning network

Network Architecture

Demilitarized Zone
  • Bastion Host
  • Gateway between trusted and untrusted network that gives limited authorized access to untrusted hosts
  • Demilitarized Zone (DMZ)
  • Isolated subnet that allows an organization to give external hosts limited access to public resources,

without granting them to internal DMZ network

  • Intrusion Detection Systems (IDS)
    Intrusion Detection Systems
  • Network Taps (Intrusion Preventions Systems)
    Intrusion Preventions Systems
  • Scanners
  • Discovery scanning
  • Compliance scanning
  • Vulnerability scanning
  • Scanning tools
  • Nessus: A vulnerability scanner
  • Nmap: A discovery scanner

Reference

  • Official (ISC)2 Guide to the CISSP CBK, Fourth Edition ISC2 Press