DAtabase security for ICT profesional, Lecture notes of Computer Science

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Database Security:

An Introduction

Introduction

 (^) Database security involves protecting the database from unauthorized access, Modification, or destruction  (^) The database design should reflect the organization’s commitment to the protection of individual privacy rights by including only those items that the organization has a right to know and keeping them secure. 

Three Basic Concepts

 (^) Authentication: a mechanism that determines whether a user is who he or she claims to be  (^) Authorization: the granting of a right or privilege, which enables a subject to legitimately have access to a system or a system’s objects  (^) Access Control: a security mechanism (of a DBMS) for restricting access to a system’s objects (the database) as a whole 4

Introduction to Database Security Issue(2)

 (^) Threats

• (^) Any situation or event, whether intentional or unintentional, that will adversely affect a system and consequently an organization
• (^) Threats to: →Computer systems →Databases

Scope of Data Security Needs

• Must protect databases & the servers on which they reside
• Must administer & protect the rights of internal database users
• Must guarantee the confidentiality of ecommerce customers as they access the database
• With the Internet continually growing, the threat to data traveling over the network increases exponentially

Introduction to Database Security Issues (3)

 (^) Threats to databases (CIA)

• (^) Loss of confidentiality
• (^) Loss of Integrity
• (^) Loss of Availability  (^) To protect databases against these types of threats four kinds of countermeasures can be implemented:
• (^) Access control
• (^) Inference control
• (^) Flow control
• (^) Encryption

Introduction to Database Security Issues 5)

 (^) The security mechanism of a DBMS must include provisions for restricting access to the database as a whole

• (^) This function is called access control and is handled by creating user accounts and passwords to control login process by the DBMS.

Introduction to Database Security Issues (6)

 (^) Another security is that of flow control , which prevents information from flowing in such a way that it reaches unauthorized users.  (^) Channels that are pathways for information to flow implicitly in ways that violate the security policy of an organization are called covert channels.

Database Security and the DBA

 (^) The database administrator ( DBA ) is the central authority for managing a database system.

• (^) The DBA’s responsibilities include →granting privileges to users who need to use the system →classifying users and data in accordance with the policy of the organization  (^) The DBA is responsible for the overall security of the database system.

Database Security and the DBA (2)

 (^) The DBA has a DBA account in the DBMS

• (^) Sometimes these are called a system or superuser account
• (^) These accounts provide powerful capabilities such as: →1. Account creation →2. Privilege granting →3. Privilege revocation →4. Security level assignment
• (^) Action 1 is access control, whereas 2 and 3 are discretionarym and 4 is used to control mandatory authorization

Discretionary Access Control

 (^) The typical method of enforcing discretionary access control in a database system is based on the granting and revoking privileges.

Types of Discretionary Privileges

 (^) The account level :

• (^) At this level, the DBA specifies the particular privileges that each account holds independently of the relations in the database.  (^) The relation level (or table level ):
• (^) At this level, the DBA can control the privilege to access each individual relation or view in the database.

Types of Discretionary Privileges(3)

 (^) The second level of privileges applies to the relation level

• (^) This includes base relations and virtual ( view ) relations.  (^) The granting and revoking of privileges generally follow an authorization model for discretionary privileges known as the access matrix model where
• (^) The rows of a matrix M represents subjects (users, accounts, programs)
• (^) The columns represent objects (relations, records, columns, views, operations).
• (^) Each position M(i,j) in the matrix represents the types of privileges (read, write, update) that subject i holds on object j.

Types of Discretionary Privileges(4)

 (^) To control the granting and revoking of relation privileges, each relation R in a database is assigned and owner account , which is typically the account that was used when the relation was created in the first place.

• The owner of a relation is given all privileges on that relation.
• (^) In SQL2, the DBA can assign and owner to a whole schema by creating the schema and associating the appropriate authorization identifier with that schema, using the CREATE SCHEMA command.
• (^) The owner account holder can pass privileges on any of the owned relation to other users by granting privileges to their accounts.