Basic Security Concepts

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Basic Security Concepts

• Threats and Attacks
• Computer Criminals
• Defense Techniques
• Security Planning

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An Example

• School district employee uses disk with student
  names and SSNs in a student computer lab
• Student later removes information from the lab
• Anderson District 5 T. L. Hanna HS
• The State, August 26, 2004

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Security Terminology

• Threat potential occurrence that can have an
  undesired effect on the system
• Vulnerability characteristics of the system that
  makes it possible for a threat to potentially
  occur
• Attack action of malicious intruder that
  exploits vulnerabilities of the system
• Risk measure of the possibility of security
  breaches and severity of the damage
• Control protective measure that reduces a
  vulnerability

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Threat or Menace?

• Hackers Threat or Menace?
• Instant Messaging Threat or Menace?
• SUVs Threat or Menace?
• Colons Threat or Menace?
• Mary Worth Threat or Menace?

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Superman

• Vulnerability
• Kryptonite
• Threat
• Possible exposure to kryptonite
• Attack
• Use of kryptonite by villain
• Control
• Lead shielding

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Roadkill

• Vulnerability
• Animals on road
• Threat
• Possible collision with animal
• Attack
• Unwise road crossing by animal
• Control
• Various

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Assessment of Risk

• Probability of Collision
• Species of animal
• Location
• Time and date
• Damage to car/occupants
• Minor or none
• Total destruction/death
• Damage to animal
• Minor scratches
• Death

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Different Animals

• Moose
• Possible high damage to car/occupants
• Low probability in South Carolina
• Deer
• Possible high damage to car/occupants
• High probability in South Carolina
• Frog
• Little or no damage to car/occupants
• High probability in South Carolina

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Possible Controls for Deer

• Defensive driving
• Knowledge of deer behavior
• Deer crossing signs
• Fences
• Diversionary feeding areas
• Expanded hunting seasons
• Roadside reflectors
• Whistles and other noisemakers
• Deer activated flashing lights

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And Now ...

• Back to Computer Security

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Sources of Threats

• Errors of users
• Dishonest insider
• Disgruntled insider
• Outsiders
• Natural disasters
• Computer system failure

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Types of Threats

• Disclosure threat dissemination of unauthorized
  information
• Alteration threat incorrect modification of
  information
• Denial of service threat access to a system
  resource is blocked

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Impact of Attack What?

• Interruption an asset is destroyed, unavailable
  or unusable (availability)
• Interception unauthorized party gains access to
  an asset (confidentiality)
• Modification unauthorized party tampers with
  asset (integrity)
• Fabrication unauthorized party inserts
  counterfeit object into the system (integrity)

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Methods of Attack How?

• Passive attacks
• Eavesdropping
• Monitoring
• Active attacks
• Masquerade one entity pretends to be a
  different entity
• Replay passive capture of information and its
  retransmission
• Modification of messages legitimate message is
  altered
• Denial of service prevents normal use of
  resources

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Computer Crime

• Any crime that involves computers or aided by the
  use of computers
• U.S. Federal Bureau of Investigation reports
  uniform crime statistics

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Computer Criminals

• Amateurs regular users, who exploit the
  vulnerabilities of the computer system
• Motivation easy access to vulnerable resources
• Crackers attempt to access computing facilities
  for which they do not have the authorization
• Motivation enjoy challenge, curiosity
• Career criminals professionals who understand
  the computer system and its vulnerabilities
• Motivation personal gain (e.g., financial)

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Methods of Defense

• Prevent block attack
• Deter make the attack harder
• Deflect make other targets more attractive
• Detect identify misuse
• Tolerate function under attack
• Recover restore to correct state

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Information Security Planning

• Organization analysis
• Risk management
• Mitigation approaches and their costs
• Security policy
• Implementation and testing
• Security training and awareness

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System Security Engineering
Specify System Architecture
Identify and Install Safeguards
Threats, Attacks, Vulnerabilities??
Prioritize Vulnerabilities
Estimate Risk
Risk is acceptably low
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Risk Management

• Risk analysis
• Risk avoidance
• Risk mitigation
• Risk acceptance
• Risk transference

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Risk Analysis Methods

• Risk Analysis
• Threats and relevance
• Potential for damage
• Likelihood of exploit

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Assets-Threat Model

• Threats compromise assets
• Threats have a probability of occurrence and
  severity of effect
• Assets have values
• Assets are vulnerable to threats

Threats
Assets
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Computing Risks

• Risk expected loss from the threat against an
  asset
• ALE AVEFARO
• ALE annualized loss expectancy
• AV -- value of asset
• EF -- exposure factor (fraction lost)
• ARO annualized rate of occurrence

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A Simple Example

• Threat Power surge
• Vulnerability Power supply
• AV computer valued at 1,000
• EF 10 loss if power surge
• SLE -- 100 (AVEF)
• ARO 2 (twice a year)
• ALE -- 200 (SLEARO)

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Cost/Benefit Analysis

• Benefit (ALE Life) - Cost
• Assume
• Surge protector costs 25
• Surge protector lasts 5 years
• ALE 200
• Benefit (200 5) - 25 975
• Buy the surge protector!!!

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System-Failure Model

• Estimate probability of highly undesirable events
• Risk likelihood of undesirable outcome

Threat
Undesirable outcome
System
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Risk Acceptance

• Certification
• How well the system meets the security
  requirements (technical)
• Accreditation
• Managements approval of automated system
  (administrative)

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Mitigation Approach

• Security safeguards
• Protection
• Assurance

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Next Class
Access Control Methodologies Who? What? When?
How?