Computer Network Security PPT

1. COMPUTER NETWORK
SECURITY
Engr. Muhammad Waseem
Department Of Computer Systems
Engineering & Sciences

2. Computer Network Security 2
Course outline
The need for network security
The Network security problem
Different types of attacks
Malicious and Non-Malicious Program Flaws
Protection in operating systems
Spoofing
Intrusion Detection Systems
Firewalls
Operating Systems Hardening
Device security
Honeypots and honeynets

3. Computer Network Security 3
Module objectives
Understand
Why we need network security
The nature of the network security problem
Defensive strategies
The gold standard
History

4. Computer Network Security 4
The need for network security
Why do you need to take this course?
Credit towards Bachelor degree
An easy A
Value for your organization

5. Computer Network Security 5
The need for network security
Value of an organization’s data
Personnel information
Financial information
Intellectual property
Proprietary information
Contact lists

6. Computer Network Security 6
The need for network security
Organizations that are at risk:
Corporate financial systems
Credit card processing systems
ATMs
Telephone systems
Emergency response infrastructure
Air traffic control
Power system

7. Computer Network Security 7
The need for network security
Almost all processes automated
No manual alternative
In case of a crash, restoration is essential

8. Computer Network Security 8
Nature of problem
Common belief: Computers are digital
devices, sharp 1s and 0s, so perfect security
should be possible
Not true
Too many contributing factors: too many
people and too many programs involved
A reasonable goal would be as good as real-
world security

9. Computer Network Security 9
Nature of problem-differences
Variety of attack methods
Can attack a lot more places
Can attack a lot more quickly
Can attack with relative anonymity
All without spending too many resources

10. Computer Network Security 10
Defensive strategies
Access Control
Keep everybody out. Disconnect your PC from the
network, and only install programs that you wrote
yourself. It will be secure, but it will be more
difficult to be worked on.
Keep the bad guy out. This can be done in a
variety of ways, such as code signing and
firewalls.
You can let the bad guy in but keep him from
doing bad things by using sandboxing or access
control.

11. Computer Network Security 11
The gold standard
Authentication, authorization, and auditing, all start with
Au, so they are also known as the gold standard.
The principle of authentication is that you have a way of
knowing what principal is taking responsibility for the
request that is being made.
Principals are usually people, but can also be channels,
servers, and programs.
For example, typically in distributed applications,
communication channels are implemented by means of
encryption, and the encryption key acts as a principal.

12. Computer Network Security 12
Cont’d
The next step is to figure out whether or not that
request coming from that party ought to be
granted. This is authorization. Typically access is
granted to principals or group of principals.
Auditing keeps track of all the activity. Auditing
analyzed logs and access requests that were made
by principals that were either granted or denied.

13. Computer Network Security 13
ANY QUESTIONS
?