1. Sources of Risks CIT304 University of Sunderland

2. References P. Neumann, 1995, Computer-Related Risks, Addison-Wesley, ISBN: 0-201- 55805-X

3. Risks in Development System conceptualization –Miss-assessment of the technology. Requirements definition –Erroneous, incomplete, or inconsistent requirements. System design –Fundamental misconceptions or flaws. Implementation –Various errors. Support systems –Faulty or poor tools. System analysis –False assumptions or erroneous models. Testing –Incomplete or erroneous testing. Evolution –Sloppy maintenance and upgrades. Decommission –Premature removal; removal of components used elsewhere.

4. Risks in Use Environment –Earthquakes, floods, fires, etc. Animals –E.g., squirrelcide. Infrastructure –Loss of power, air conditioning Hardware –Malfunction due to ageing or transients Software –Bugs Communications –Outages, interference, and jamming Human Limitations –Installation or misuse

5. Note Well… Risks are not just security… By the way, security risks tend to be: –Mostly involving insiders –Mostly involving human behavior –Sometimes resulting from unwarranted assumptions –Often are due to design errors or incomplete understanding of a system or technology

6. System Conceptualization Misunderstanding of the technology –Too far –Not far enough Cost overruns Schedule overruns Lack of Feasibility Example—MIFASS (Marine Fire and Air Support System). The agency direction was to use a CPU somewhat slower than a first generation Apple II. There was no recovery.

7. Requirements Definition Erroneous requirements Incomplete requirements Inconsistent requirements Extremely common and expensive. Missing requirements are the worst problem.

8. System Design Fundamentally false assumptions –E.g., infinite speed of light Erroneous models Example: the FAA’s Advance Automation System. The contractor assumed that the average statement in Ada generated 5 machine instructions (actually it was 10) and that the speed of a 10 MHz machine was (with parallelism) 20 MHz (actually it was 12 MHz). There was no recovery.

9. Implementation Various and varied. –Chip fabrication (Intel’s early Pentium chip) –Wiring –Programming bugs –Trojan horses –Viruses We will discuss this.

10. Support Systems Faulty or poor tools –Language choice –Compiler/debugger –Bad tools –Editing CASE tools never met their expectations… Sometimes reflect failure to meet standards. Sometimes is deliberate on the part of a vendor.

11. System Analysis False assumptions about –World –Operating environment –Human behavior Erroneous models and simulations Prototypes help here.

12. Testing Incomplete testing Erroneous testing Faulty code verification What is a testable requirement? One way of dealing with this is Test-Driven Development (TDD), where you write the unit tests first. We teach this in CSE301.

13. Evolution Sloppy maintenance and upgrades. Misconceptions New flaws Loss of design coherency Maintenance organizations do not attract the best engineers. Design the system so it can be maintained by entry-level staff.

14. Decommission Premature removal. Removal of components needed elsewhere. Hidden dependencies Replacement not done in time Hardware and software end of life Vendor profiteering

15. Environment Earthquake Flood Fire Temperature extremes EMI Etc…

16. Animals Sharks (underwater cables) Squirrels (enjoy fibre and cabling) Monkeys (inquisitive) Birds (watch your neighborhood telephone poles) Horses (enjoy practical jokes) Cattle Pigs Etc.

17. Infrastructure Power Air Conditioning Physical Security

18. Hardware Ageing Transients Environmental problems Errors in Design

19. Software Bugs of many sorts –System development –Change implementation –Maintenance

20. Communications Outages Natural interference Jamming –Intentional –Accidental Tapping Other

21. Human Error Installation Misuse –Intentional –Unintentional

22. Adverse Effects A myriad Discuss…