Logging Mechanism Nonrepudiability Metrics

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Logging Mechanism Nonrepudiability Metrics

Jason King

Computer Science PhD Student

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Repudiation Threats Users can deny performing an action without other parties having any way to prove otherwise

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Nonrepudiation • Counter repudiation threats • Secure activity logs

– Includes events that create, delete, view, modify sensitive data

– Includes security events – Protects log entries from being altered

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Research Objective

• Improve integrity of logging mechanisms •Mitigate repudiation threats • Developing and validating a set of security

metrics

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Logging Mechanism References •Healthcare •Payment Card Industry •Research Articles

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Electronic Health Record System OpenEMR Example

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Electronic Health Record System PatientOS Example

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Electronic Health Record System OpenEMR Immutability

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Attributes of Nonrepudiation

• Data transactions logged • Security actions logged • Log entry content • Software-driven immutability

• Timestamp reliability • Log retention • Log backups • Policy-driven immutability

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Data Transactions Logged

Derive from requirements specification

Create View

Delete

Modify

Import

Query Export

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Natural Language Processing of Functional Requirements

Subject Verb Direct Object A doctor creates prescriptions A patient views allergy information A doctor modifies office visit notes

[Subject] [Verb] [Direct Object]

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Data Transactions Logged Example

Health Care Personnel can modify or delete the fields of the office visit [prescriptions, laboratory procedures, referrals,

diagnoses, and/or immunizations]. Data Element Create View Modify Delete

Prescription X X

Lab Procedure X X

Referral X X

Diagnoses X X

Immunization X X

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Security Actions Logged Login Logout

Revoke Privilege

Grant Privilege

System Backup

Access Audit Log Initialize Audit Log

System Restore Session Timeout

Account Lockout Print …

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Required for Nonrepudiation Additional Content Timestamp Source Machine ID User identification Success/Failure Flag Description of the event ID of affected data Identify of whose data accessed Reason for access

Log Entry Content Data captured for each log entry

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Logging Mechanism Evaluation

Software User Actions Log Output

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Software-driven Immutability

• Tampering with log files should be detectable – Serialization/digital signatures of log files – Provenance tracking of data writes

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Preliminary EHR Evaluation

0%

25%

50%

75%

100% Data Transactions Logged

Security Actions Logged

Log Entry Content

Software-based Immutability

OpenEMR v4.1.1

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Preliminary EHR Evaluation

0%

25%

50%

75%

100%

Data Transactions Logged

Security Actions Logged

Log Entry Content

Software-based Immutability

OpenEMR v4.1.1 PatientOS v1.3

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Collaboration

Requirement artifacts

Software access for black-box testing

Log Output

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Collaboration

Requirement artifacts

Software access for black-box testing

Log Output

Logging strengths

Logging weaknesses

Functional logging requirements

Mitigate repudiation threats

Science of Security Lablet

Security Metrics-Driven Evaluation, Design, Development, & Deployment

Logging Mechanism Nonrepudiability Metrics

Jason King

Computer Science PhD Student