Sources of Risks

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
• ExampleMIFASS (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 FAAs 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 (Intels 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