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

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

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

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

• 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)
  
• Network Taps (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