Presented By Katherine L. Morse

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Presented ByKatherine L. Morse
April 22, 1999
The 8-Stage Security Specific Risk
Assessment Methodology
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Outline

• Motivation
• The Eight-Stage Model
• Methodology
• Example
• Lessons Learned
• Future Research
• Conclusions

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Motivation

• Auditing as a countermeasure
• Flaws in existing risk assessment methodologies
• Formulating the chain of events
• Evaluating all countermeasures against all
  threat/vulnerability pairs
• Spotlighting high risk threat scenarios

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The Eight-Stage Model

• Security Threat
• Security Breach
• Resultant Harm

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The Eight Stage Model (continued)
Security Breach
Threat Recovery
Breach Recovery
Threat Obstruction
Threat Detection
Breach Detection
Resultant Harm
Security Threat

• Prevention
• Threat Obstruction
• Detection
• Threat Detection
• Breach Detection
• Recovery
• Threat Recovery
• Breach Recovery

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Methodology

• Driven by threats
• Threat scenario for each threat
• Improvements to traditional methodology
• Chain of events
• Countermeasures act at several stages
• Only evaluate threats against applicable
  countermeasures

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Example

• Warning banner on login prompt
• Hacker attack
• Auditing with intrusion detection
• Firewall, tools for hacker tracking
• Gain root access
• Compromise of data
• Loss of integrity of data and/or system
• Loss of data and/or resource availability

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Example (continued)

• Auditing
• Hot spare, close net access
• Harms
• Failure of business or mission
• Loss of personnel
• Loss of resources
• Loss of dollars
• Loss of time

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Lessons Learned

• Few threat scenarios
• Types of breaches few in number
• Many countermeasures meet several threats with
  varying effectiveness
• Probabilities for detection and recovery from the
  breach are the same regardless of the motivating
  threats
• The initial result is less numerical analysis
• The final result is a more readable document with
  a clearer correlation between the real threat and
  the real changes that need to be made in the
  system

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Future Research

• Automated tools
• Integration with existing risk calculation
  methodologies
• Tandem threats
• Temporal factors
• Expiration of sensitivity
• Duration of resistance
• Cost vs. value
• Prevention
• To attacker

8-Stage Security