1. G53SEC
Computer Security
Introduction to G53SEC 1

2. Overview of Today’s Lecture:
G53SEC
Overview of Today’s Lecture:
Instructor Information
Module Structure
Grading
Motivation for the Module
Module Contents
Textbook and Additional References
Summary 2

3. Name: Milena Radenkovic E-mail: mvr@cs.nott.ac.uk Room: B47
G53SEC
Contact Information:
Name: Milena Radenkovic
Room: B47
Course Website:
Please contact me via before coming to see me in my office!
Even though Dr. Aickelin is stated as the module Convener, I will be in charge of lecturing and any request about the course and its contents is to be directed to me. 3

4. Theoretical Part – Lectures
G53SEC
Module Structure
Theoretical Part – Lectures
Given by me as well as various guest lecturers
2 hours / week
Thursday 09:00 -10:00, Jubilee Campus, Exchange Building, C3
Friday 12:00 – 13:00, Jubilee Campus, Exchange Building, C3
Practical Part – Coursework
Assignments on protecting and identifying security vulnerabilities and improving of defences of hosts and networks (TBA)
Lab access
Practical part – might give some guidance on where to look for software and tips on how to do penetration testing, defence, etc… 4

5. 1 hour written examination 60 %
G53SEC
Grading:
1 hour written examination 60 %
(Contents from all lectures examinable . Guest lectures can be used as examples but not examinable in detail.)
Coursework 40 % 6

6. People protect their property and privacy for generations
G53SEC
Motivation
People protect their property and privacy for generations
(Locks, Fences, Signatures, Seals, etc…)
Big change
Everything becoming electronic
And Security?
What about Future? 6

7. What is computer/information security ? Why is it so important ?
G53SEC
What will you learn
What is computer/information security ?
Why is it so important ?
How to evaluate and measure it ?
How to enforce it ?
How to minimise its risks ?
The bad guy’s point of view
The victim’s point of view 7

8. Resources Course Text:
G53SEC
Resources
Course Text:
Computer Security – Dieter Gollmann 2nd edition (Amazon)
Security Engineering – Ross Anderson
(Available online)
Additional Reading:
Secrets & Lies – Bruce Schneier
Computer Security: Art and Science –
Matt Bishop
Course Website (Links, Slides, etc…)
Ideally read the relevant chapter from the course text before coming to the lecture, this will make it much easier to remember and learn the actual contents. 8

9. G53SEC
End of Part 1 9

10. Introduction to Security
G53SEC
Introduction to Security 1

11. Risk and Threat Analysis
G53SEC
Outline
On Security
Attacks and Attackers
Security Management
Security Policies
Measuring Security
Standards
Risk and Threat Analysis
Assets
Vulnerabilities
Threats
Risks
Countermeasures 2

12. A secure system is one which does not exist…
G53SEC
A secure system is one which does not exist…
It is not about achieving complete security
It is about minimising risk to systems
Both from a technical as well as social point of view
An almost secure system is one which is locked up in a nuclear bunker within an air locked titanium safe and disconnected from anything else in the world……and even such a system is not 100% secure! 3

13. Original focus on multiuser systems
G53SEC
On Security
Original focus on multiuser systems
Today focus on ubiquitous end systems
Systems interconnected by networks
Danger of possible attacks from ‘un-trusted’ nodes
Both remotely as well as locally (insiders)
Primarily a management issue! 4

14. Script kiddies -> Organized crime
G53SEC
Attacks and Attackers
Landscape is changing
Script kiddies -> Organized crime
Website defacement -> Personal data harvesting
Peer appreciation -> Earning money
Viruses -> Trojans and Denial-of-Service attacks
Complexity of our systems is increasing
Our understanding of the system’s intricacies can’t keep up 5

15. Reliability – Accidental failures Usability – Operating mistakes
G53SEC
Security
Reliability – Accidental failures
Usability – Operating mistakes
Security – Intentional failures
‘Security is a people problem’
Legal system defines boundaries of acceptable behaviour
Management responsible for security 6

16. Management responsible for assets
G53SEC
Security Management
Management responsible for assets
Security measures must have clear full support of senior management
Security awareness programs
User is not the enemy!
Developers need even more awareness!
Security awareness – why security is important
- what is expected of each member
- which good practices should be followed 7

17. State what should be protected And how this should be achieved
G53SEC
Security Policies
State what should be protected
And how this should be achieved
Security Policy Objective
Organizational Security Policy
Automated Security Policy 8

18. Measures only exist for some aspects of security
G53SEC
Measuring Security
Very difficult
Measures only exist for some aspects of security
Product Security
System Security
Cost of an Attack
Cost of Assets 9

19. Risk and Threat Analysis
G53SEC
Risk and Threat Analysis
Risk Analysis
- All information assets
IT infrastructure
During development
Risk – Possibility of an incident or attack to cause damage to your enterprise
Risk = Assets * Threat * Vulnerabilities 11

20. Identification easy, valuation difficult
G53SEC
Assets
Software
Hardware
Data and Information
Reputation
Identification easy, valuation difficult
Data, Information, Reputation – difficult to measure 12

21. Badly configured accounts Programs with known flaws
G53SEC
Vulnerabilities
Weaknesses of a system that could be accidentally or intentionally exploited to damage assets
Badly configured accounts
Programs with known flaws
Weak access control
Weak firewall configuration
Can be rated according to impact 13

22. Categorisation by damage done to assets
G53SEC
Threats
Actions by adversaries who try to exploit vulnerabilities to damage assets
Categorisation by damage done to assets
Identification of source of attacks
Analysis of attack execution (Attack Graphs)
Can be rated according to likelihood
Attack Graphs - formalized and structured
- assessable, reproducible
Identification – insider/outsider/contractor/fired employee
Attack Graphs – Tedesco’s Research 14

23. Quantitative Risk Analysis
G53SEC
Risk
Quantitative Risk Analysis
+ probability theory based on mathematical theory
- quality of results depends on quality of inputs
- not always feasible
Qualitative Risk Analysis
+ more applicable
- scaling based on judgements of security experts
Scaling – critical – very important – important – not important 15

24. Countermeasures / Risk Mitigation
G53SEC
Countermeasures / Risk Mitigation
Risk analysis presents recommended countermeasures
Risk analysis not always possible
Baseline protection – security requirements for typical cases with recommended countermeasures
RA not possible due to cost, time, unjustifiable to management 16

25. Current security landscape Management is vital to security
G53SEC
Summary
Current security landscape
Management is vital to security
How security can be measured
What is Risk and how it is analysed
Next Lecture: Foundations of Security – What security actually is? 17

26. G53SEC
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