Definition of Computer Security

Goals of Computer Security

Tools and Processes for Computer Security

Practical Computer Security Solutions

No True Definition

Defined by a set of goals

Goals are set case by case

Normally found in a security policy

Integrity

• Information should be able to be trusted as being correct
• Programs should only do what they are intended
• Sources of information should be able to be trusted

Confidentiality

• Information should only be accessed by authorised users
• If confidentiality is broken then it should be made known

Availability

• Computer Systems should always be availaible to authenticated users
• Information should always be available to authenticated and authorised users
• If a system becomes unavailable there should be predefined time-frames for availability

User Awareness

• The most important aspect
• Typically in a Security Policy
• 80% of security breaches are internal

Physical Protection

• A system does not need to be running to be compromised
• Security mechanisms can be bypassed if you have physical access

Access Control

• Who can access what from where at what time
• Implemented by access control lists (ACL) and login windows

Auditing

• If you have been compromised, how are you going to know?
• Can be system logs, system checksums

Cryptography

• Maintain confidentiality by encrypting data
• Maintain integrity of source by digitally signing

Backups

• Very important, allows for availability of data

Restrictive Security

• Assume everything is bad unless explicity good
• As opposed to permissive

Defence in Depth

• Don't let the bad guys in
• Can seperate an sensitive internal network from a general users

Intrusion Detection Systems

• Watch for known attack patterns, informing the network admin
• Can be network or host based

PGP

• Allows for encrypting files
• Allows authentication of a user