Database Security Jagdish S. Gangolly School of Business State University of New York at Albany NOTE: These notes are based on the book Security in Computing, by Charles & Shari Pfleeger, and are prepared solely for the students in the course Acc 661 at SUNY Albany. They are not to be used by others without the permission of the instructor. 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Acc 661 Auditing of Adv Acctg Info Systems Database Security Security requirements Physical database integrity Logical database integrity Element integrity Auditability Access control User authentication Availability 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Example of Oracle DBMS Architecture Source: http://www.wilsonmar.com/1oraarch.htm 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Database Integrity & Auditability Field Checks (Domain) Access control Maintenance of change log Granularity problem Pass-through problem Direct access of data vs. Inference problem 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Database reliability & Integrity Two-phase update: intent phase and commit phase Redundancy/internal consistency Error correction codes Shadow fields Backup and recovery procedures Concurrency/Consistency/Deadlock management Monitors and range comparisons State constraints (eg., commit flag) and Transition constraints (eg., referential integrity) 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Acc 661 Auditing of Adv Acctg Info Systems Inference Problem Direct vs. Indirect attacks Tracker attacks: count((SEX=F)  (RACE=C)  (DORM=Holmes)) = count(SEX=F) – count((SEX=F)  ((RACE  C) (DORM  Holmes))) Linear system vulnerability (inference by solving equations) 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Controls against Inference Attacks Controls applied against queries Controls applied against individual items in the database Suppression: sensitive data values are not provided (query is rejected) Concealment: answer provided is close, but not the actual value Limited response suppression: Low frequency elements are not displayed 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Approaches to the Inference Problem Suppress obviously sensitive information Track what the user knows Disguise data (random perturbation, rounding, …) 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems

Acc 661 Auditing of Adv Acctg Info Systems 12/6/2018 Acc 661 Auditing of Adv Acctg Info Systems