1. Security and Integrity

2. Database security and Authorization
Introduction to security issues
Mechanisms used to grant and revoke privilege in relational database in SQL
An overview of the mechanisms for enforcing multiple levels of security
Briefly discusses the security problem in statistical database
Introduces flow control and mentions problems associated with convert channels.
A brief summary of encryption and public key infrastructure schemes.
Summaries the chapter

3. What is security?

4. Introduction to Database Security Issues
Types of Security
Legal and ethical issues regarding the right to access certain information. In US there are many laws governing privacy of information.
Policy issues at the governmental, institutional, or corporate level as to what kinds of information should not be made publicly available – for example, credit ratings and personal medical records
System-related issues such as the system levels at which various security functions should be enforced-- for example, whether a security function should be handled at the physical H/W, OS, or DBMS levels.
The need in some organizations to identify multiple security levels and to categorize the data and users based on these classified. The security policy of the organization with respect to permitting access to various classifications of data must be enforced.

5. Threats to Database
Threats to database result in the loss or degradation of some or all of the following security goals: integrity, availability, and confidentially.
Loss of integrity
Loss of availability
Loss of confidentially

6. Loss of integrity
Integrity refer to requirement that information be protected from improper modification.
Modification of data includes
Creation
Insertion
Modification
Deletion
Change the status of data
Integrity is lost if unauthorized changes are make to the data by either intentional or accidental acts.
If continue use the contaminated system or corrupt data cause the result in inaccuracy, fraud, or erroneous decision

7. Loss of availability
Database availability refers to making objects available to human user or a program to which they have a legitimate right

8. Loss of confidentially
Database confidentially refers to the protection of data from unauthorized disclosure.
The impact range from
Violent of data privacy act to the damage of national security
Unauthorized could result in loss of public confidence, embarrassment, or legal action against the organization.

9. How to protect database
To protect database against these types of 4 kinds of countermeasures can be implemented:
Access control
Inference control
Flow control
Encryption

10. Database security mechanisms
Discretionary security mechanisms
Grant privilege to users, includes the capability to access specific data files, records, or fields in a specified mode (insert, read, delete, update)
Mandatory security mechanisms
Classifying the data and users into various security classes
Implementing the appropriate security policy of the organization
Example
Policy to permit users at a certain classification level to see only the data item classified at the user’s own (or lower) classification level.
Role-based security

11. Database security and the DBA
DBA has a DBA account in the DBMS
Called “system” or “superuser” account
Provide powerful capabilities that are not available for regular database accounts and users.
DBA privilege commands include commands
for granting and revoking privilege to individual accounts, users or user groups
For performing the followings
Account creation
Privilege granting
Privilege revocation
Security level assignment
DBA response for the overall security of the database system.

12. Access Protection, User accounts, and Database Audits
Person need to access database
DBA create user account and password
The user login to the DBMS by enter user account and password
The DBMS checks that the account and password valid
If the user is permitted to use the DBMS to access the database
DBMS keep track of database users and their accounts and passwords by creating and encrypted table of file with the two fields Account and Password. This table was maintained by the DBMS.
When create new user, the data will insert into this table
When account is canceled, the corresponding record must be delete from the table

13. Keep track of operation
BDMS keep track of operations on the database
Create login session when user log in
Keep track of sequence of database interactions from the time of logging in to the time of logging out
When user log in, the DBMS record the user’s account and associate it with the terminal from with the terminal from which the user logged on
All operations applied from that terminal are attributed to the user’s account until the log off
Keep track of the update operation
If the database is tampered with, the DBA can find out which user did the tampering

14. System log Keep track of operations on system log
System log includes an entry for each operation applied to the database that may be required for recovery from a transaction failure or system crash.
If have any tampering with database, a database audit is performed, which consists of reviewing the log to examine all accesses and operations applied to the database during a certain time period.
When illegal or unauthorized is found, the DBA can determine the account user
Database audits is important for sensitive databases that are updated by many transactions and users. Audit trail is a database log that used mainly for security purposes.

15. Discretionary Access control Based on Granting and Revoking Privilege
Type of Discretionary Privilege
Account level: the DBA specifies the particular privilege that each account holds independently of the relations in the database
Relation level: the DBA/owner can control the privileges to access each individual relation or view in the database

16. Account level

17. Relation level

18. SQL SELECT privilege on R: MODIFY privileges on R:
REFERENCES privileges on R:
**Remark: create view, the account must have select privilege on all relations in invoked in view definition.

19. Specifying Privilege using VIEW
Important method to limiting users to manipulate data
If user A want user B to be able to retrieve only some field of relation R (create by A)
Then A can a view V of R that includes only some attributes
And then grant SELECT on V to B

20. Grant privilege
Grant operation on Table/View to User with grant option
Example
GRANT select ON emp to tori;
GRANT select ON empcom to nok with grant option;
GRANT update on emp (salary) to tori;
GRANT all on emp to nok with grant option;

21. example Tori : Grant select on student to Hana;
Hana: Select * from Tori.student;
Tori : Grant select, update on student to kawa with grant option;
Kawa: Grant select on student to Nara with grant option;
Question: Can Nara grant her privilege to others?
If No, why?
If yes, what privilege nara can grant to other users?

22. Syntax for create view by SQL (oracle)
CREATE VIEW View_name AS SELECT col1,col2,…,coln
FROM table1,…,tablen WHERE condition;
EXAMPLE
DEPT (DEPTNO, DNAME, LOC)
EMP (EMPNO, ENAME, JOB, MGR, SAL, COMM, DEPTNO)
CREATE VIEW EMPCOM
AS Select Empno , Ename, Sal, Comm, E.DeptNo, Dname
FROM EMP E, DEPT D
WHERE E.DeptNo = D.DeptNo and Comm > 0;
EMPCOM
EMPCOM (Empno , Ename, Sal, Comm, DeptNo, Dname)

23. Revoking Privileges Purpose for canceling privileges
REVOKE operation on table/view/object from USER
Example
REVOKE select on EMP from tori;
REVOKE select on EMPCOM from tori;

24. Propagation of Privileges using the Grant Option
User A create table R (A is owner of R)
GRANT
User A grants Privilege on R to User B with grant option (mean B can also grant that privilege on R to other accounts).
User B give grant privilege to User C with grant option
This mean privilege on R can propagate to other accounts without the knowledge of the owner of R
REVOKE
If A revoke privilege on R from B.
All privilege that B propagated should automatically be revoked by the system.
User receive a certain privilege from two or more sources.
A2 and A3 give certain UPDATE privilege on R To A4
IF A2 revokes the privilege from A4
A4 will still continue to have to privilege by virtual grant from A2
IF A3 revokes the privilege, the A4 totally lose the privilege on R
การแพร่กระจายของสิทธิในการใช้งาน

25. Role-based Access control (RBAC)
RBAC emerged rapidly in 1990s
A proven technology for managing and enforcing security in large scale enterprisewide system.

26. Example
ORACLE
System level role provide by oracle has 3 roles: CONNECT, RESOURCE, and DBA
Create Role
Create role role_name not identified
Create role role_name identified by password
Example
CREATE role APPL_ROLE not identified
GRANT connect to APPL_ROLE
GRANT resource to APPL_ROLE
GRANT select on student to APPL_ROLE
GRANT select, update on student to APPL_ROLE
GRANT APPL_ROLE to TORI
REVOKE update on student from APPL_ROLE
Connect give privileges creating sessions in the database. This role gives the following system privilege to user: Alter session, create synonym, create table, create view. But user can not create table on table space unless you grant them a quota on a tablespace.
RESOURCE role has the following system privileges: create cluster, index, procedure, sequence, table, trigger,
DBA is grant with grant option
CREATE