Risk AssessmentRisk Assessment

Farrokh Alemi, Ph.D.

Monday, July 07, 2003

Components of Risk AnalysisComponents of Risk Analysis

EPHI boundary definition Threat identification Vulnerability identification Security control analysis Risk likelihood determination Impact analysis Risk determination Security control recommendations

Based on Steve Weil’s recommendations

Step 1: EPHI Boundary Step 1: EPHI Boundary Definition Definition

Inventory of Information system hardware and software details, including: – Internal and external interfaces of information systems – Identification of the primary users of the information

systems and EPHI – Basic function and purpose of the EPHI and

information system – Technical controls (e.g., hardware or software access

control mechanisms, encryption) and non technical controls (e.g., security policies, employee training) being used to protect EPHI and information systems

Step 2: Threat IdentificationStep 2: Threat Identification

Natural: floods, earthquakes, tornados, etc.Human: unintentional (incorrect data entry

or accidental deletion of data) and intentional (denial of service attack, installing malicious software).

Environmental: power failures, hazardous material spill, etc.

Step 3: Vulnerability Step 3: Vulnerability IdentificationIdentification

Vulnerability lists such as the NIST vulnerability database (http://icat.nist.gov)

Trace the “footprint”Defined rules of engagement (what time of

day the assessments can occur, what types of attacks are appropriate, what systems will be assessed, etc.) BEFORE the assessment begins

Step 4: Security Control Step 4: Security Control AnalysisAnalysis

Access controlAuthenticationAudit trailAlarm

Step 5: Risk Likelihood Step 5: Risk Likelihood DeterminationDetermination

Three factors should be considered: – Threat motivation and capability – Type of vulnerability– Existence and effectiveness of security controls

Numerical rating of risks– Frequency– Subjective probability

Divide and conquer Group consensus Estimate-talk-estimate Upper and lower limits

Step 6: Impact AnalysisStep 6: Impact Analysis

Confidentiality: EPHI is disclosed or accessed in an unauthorized manner

Integrity: EPHI is improperly modified Availability: EPHI is unavailable to

authorized users

Step 7: Risk DeterminationStep 7: Risk Determination

Aggregate risks from individual factors to identify risk for a specific system containing EPHI– Under assumptions of independence Bayes

formula could be used Posterior odds of security breach is equal to prior

odds multiplied by likelihood ratios of each threat

Step 8: Security Control Step 8: Security Control RecommendationsRecommendations

MitigateEliminateInsureHedge

Sample surveysSample surveys

Ontario Privacy Diagnostic ToolsHIPAA Compliance Gap IdentificationEDI risk assessment check list