1. Database Security

2. Reading assignments Required: Pfleeger: Chapter 6 (except 6.3)
Multilevel Secure Relational Data Model (S. Jajodia, R. S. Sandhu. Toward a Multilevel Secure Relational Data Model. Proc ACM Int'l. Conf. on Management of Data (SIGMOD), )
Recommended:
Polyinstantiation (Sushil Jajodia, Ravi S. Sandhu, and Barbara T. Blaustein, Solutions to the Polyinstantiation Problem,
MLS/RDMS Architectures (LouAnna Notargiacomo, Architectures for MLS Database Management Systems
CSCE Farkas

3. Database Management System (DBMS)
Collection of
interrelated data and
set of programs to access the data
Convenient and efficient processing of data
Database Application Software
CSCE Farkas

4. Data Models A collection of tools for describing Data
Relationships among data items
Semantics of stored data
Database constraints
CSCE Farkas

5. Relational Data Model Works Person-name Company-name Salary Smith BB&C
$43,982
Dell
Bell
$97,900
Black
$35,652
CSCE Farkas

6. Relational Data Model Set of relation names: R
Set of attribute names: A
Relation schema: S=(r,{a1, …,an})
r relation name in R
{a1, …,an} subset of A
e.g., (Works,{person-name,company-name,salary})
CSCE Farkas

7. Tuple (Record) e.g., t(person-name)=Smith
Tuple over a relation scheme S is a mapping
t: {a1, …,an}  dom(a1  …  an)
e.g., t(person-name)=Smith
t(company-name)=BB&C
t(salary)= $43,982
CSCE Farkas

8. Relation Relation over schema S is a set of tuples over the scheme
e.g.,
t(person-name)=Smith, t(company-name)=BB&C, t(salary)=$43,982
t’(person-name)=Dell, t’(company-name)=Bell, t’(salary)= $97,900
t”(person-name)=Black, t”(company-name)=BB&C, t”(salary)= $35,652
CSCE Farkas

9. Database Database: set of relations e.g., EMPLOYEE database:
Lives(person-name,street,city)
Works(person-name,company-name,salary)
Located-in(company-name,city)
Manages(person-name,manager-name)
CSCE Farkas

10. Query Languages Relational Algebra SQL Set operations Bag operations
CSCE Farkas

11. Relational Algebra Select () Project () Set difference (-) Union ()
Rename (Px(r))
Set intersection ()
Natural join ()
CSCE Farkas

12. Structured Query Language SQL
Typical SQL query form: SELECT A1, A2, ..., An FROM r1, r2, ..., rm WHERE C
Ais represent attributes to be returned
ris represent relations
C is a condition
CSCE Farkas

13. Constraints Relationship among data elements
DBMS should enforce the constraints
Types
Keys
Foreign-key (referential integrity)
Value-based constraints
Integrity constraints
Database dependencies (e.g., functional dependencies)
CSCE Farkas

14. Database Security Requirements
Physical database integrity
Logical database integrity
Element integrity
Auditability
Access control
User authentication
Availability
CSCE Farkas

15. Sensitive data Inherently sensitive From a sensitive source
Declared sensitive
Part of a sensitive attribute or record
In relation to previously disclosed information
CSCE Farkas

16. Types of disclosures Exact data Range of data Negative results
Existence
Probable values
CSCE Farkas

17. Access control Operating system Database Management System
Granularity!
CSCE Farkas

18. Granularity Database Relation Record Attribute Element
Advantages vs. disadvantages
of supporting
different granularity levels
CSCE Farkas

19. Relation-Level Granularity
(Works)= Secret
Person-name
Company-name
Salary
Smith
BB&C
$43,982
Dell
Bell
$97,900
Black
$35,652
CSCE Farkas

20. Tuple-level Granularity
Works
Person-name
Company-name
Salary 
Smith
BB&C
$43, P
Dell
Bell
$97, S
Black
$35, P
CSCE Farkas

21. Attribute-Level Granularity
Works
Person- name =P
Company-name =P
Salary
=S
Smith
BB&C
$43,982
Dell
Bell
$97,900
Black
$35,652
CSCE Farkas

22. Cell-Level Granularity
Works
Person-name
Company-name
Salary
Smith P
BB&C P
$43, S
Dell S
Bell S
$97, S
Black P
BB&C S
$35, S
CSCE Farkas

23. Access Control Mechanisms
Security through Views
Stored Procedures
Grant and Revoke
Query modification
CSCE Farkas

24. Security Through Views
Assign rights to access predefined views
CREATE VIEW Outstanding-Student
AS SELECT NAME, COURSE, GRADE
FROM Student
WHERE GRADE > B
Problem:
Difficult to maintain updates.
CSCE Farkas

25. Security Through Views
Student relation
NAME
COURSE
GRADE
SEMESTER
White
CSCE 122 C+
Fall 2000
Black
CSCE 313 A
Brown
CSCE 580
Spring 2000
Green
CSCE 850 B+
Blue B
CSCE Farkas

26. Security Through Views
CREATE VIEW Outstanding-Student
AS SELECT NAME, COURSE, GRADE
FROM Student
WHERE GRADE > B
Outstanding-Student
NAME
COURSE
GRADE
Black
CSCE 313 A
Brown
CSCE 580
Green
CSCE 850 B+
CSCE Farkas

27. Security Through Views
CREATE VIEW Fall-Student
AS SELECT NAME, COURSE
FROM Student
WHERE SEMESTER=“Fall 2000”
NAME
COURSE
White
CSCE 122
Black
CSCE 313
Green
CSCE 850
Blue
Fall-Student
CSCE Farkas

28. Stored Procedures Assign rights to execute compiled programs
GRANT RUN ON <program> TO <user>
Problem:
Programs may access resources for which the user who runs the program does not have permission.
CSCE Farkas

29. Grant and Revoke GRANT <privilege> ON <relation>
To <user>
[WITH GRANT OPTION]
GRANT SELECT * ON Student TO Matthews
GRANT SELECT *, UPDATE(GRADE) ON Student TO FARKAS
GRANT SELECT(NAME) ON Student TO Brown
GRANT command applies to base relations as well as views
CSCE Farkas

30. Grant and Revoke REVOKE <privileges> [ON <relation>]
FROM <user>
REVOKE SELECT* ON Student FROM Blue
REVOKE UPDATE ON Student FROM Black
REVOKE SELECT(NAME) ON Student FROM Brown
CSCE Farkas

31. Non-cascading Revoke A B C D E F A revokes D’s privileges E B A F C
Lecture 17
CSCE Farkas

32. Cascading Revoke A B C D E F A revokes D’s privileges B A C Lecture 17
CSCE Farkas

33. Positive and Negative AuthorizationB C E D + -
Problem:
Contradictory authorizations
GRANT <privilege> ON X TO <user>
DENY <privilege> ON X TO <user>
Lecture 17
CSCE Farkas

34. Negative AuthorizationB C E D + - -
Positive authorization granted
By A to D becomes blocked but
NOT deleted.
Lecture 17
CSCE Farkas

35. Negative AuthorizationB C E D + - - + F
What should happen with the privilege given by D
To F? (Blocked but not deleted)
Lecture 17
CSCE Farkas

36. Query Modification
GRANT SELECT(NAME) ON Student TO Blue WHERE COURSE=“CSCE 590”
Blue’s query:
SELECT *
FROM Student
Modified query:
SELECT NAME
WHERE COURSE=“CSCE 580”
CSCE Farkas

37. Next Class:
Inference Problem
Lecture 17
CSCE Farkas