Security Dale-Marie Wilson, Ph.D.

Why Database Security? Data Valuable resource Must be strictly controlled and managed Corporate resource Have strategic importance Must be secure and confidential

Database Security Mechanisms that protect database against intentional or accidental threats Does not only apply to data held in database Security breaches may affect other parts of system Eventually affect database

Database Security Involves measures to avoid: Theft and fraud Loss of confidentiality (secrecy) Loss of privacy Loss of integrity Loss of availability Threat Any situation or event, intentional or unintentional, that adversely affects system => organization

Summary of Threats to Computer Systems

Typical Multi-user Computer Environment

Countermeasures – Computer-Based Controls Concerned with physical controls to administrative procedures and includes: Authorization Access controls Views Backup and recovery Integrity Encryption RAID technology

Countermeasures – Computer-Based Controls Authorization The granting of a right or privilege, which enables a subject to legitimately have access to a system or a system ’ s object Mechanism that determines whether user is, who he/he claims

Countermeasures – Computer-Based Controls Access control Granting/revoking of privileges Privilege Allows user to create or access (read, write, modify) database object (relation, view, index) or run DBMS utilities Granted to user to accomplish tasks required for jobs

Countermeasures – Computer-Based Controls Discretionary Access Control (DAC) Provided by most DBMS Effective Weakness Unauthorized user can trick authorized user into disclosing sensitive data SQL standard supports DAC GRANT and REVOKE commands GRANT command Gives privileges to users REVOKE command Takes privileges from users

Countermeasures – Computer-Based Controls Mandatory Access Control (MAC) Based on system-wide policies Cannot be changed by individual users Not supported by SQL standard Each database object assigned a security class Each user assigned a clearance for a security class Rules are imposed on reading and writing of database objects by users

Countermeasures – Computer-Based Controls MAC Determines whether user can read/write object Based on rules of security level of object and clearance of user Rules ensure sensitive data never ‘passed on’ to another user without necessary clearance

Bell-LaPudula Model Each database object assigned security class Each subject assigned clearance Four classes: Top secret (TS), Secret (S), Confidential (C), Unclassified (U) TS > S > C > U Two restrictions: 1. Simple Security property Subject S is allowed to read Object O only if class(S) >= class(O) 2. *_Property Subject S is allowed to write object O only if class(S) <= class (O)

Popular Model for MAC called Bell-LaPudula

Countermeasures – Computer-Based Controls View dynamic result of one or more relational operations operating on base relations to produce another relation Virtual relation Produced upon request by particular user, at time of request Backup Process of periodically taking copy of database, log file, programs to offline storage media Journaling Process of maintaining log file/journal of all changes made to database to enable effective recovery in event of failure

Countermeasures – Computer-Based Controls Integrity Prevents invalid data Misleading or incorrect results Encryption Encoding of data by special algorithm Renders data unreadable by any program without decryption key

RAID (Redundant Array of Independent Disks) Technology DBMS hardware must be fault-tolerant Continues to operate even if one hardware components fails Main hardware components include: Disk drives, disk controllers, CPU, power supplies, cooling fans Disk drives most vulnerable component Has shortest times between failures of other hardware components Suggests having redundant components Seamlessly integrated into working system whenever component failure occurs

RAID (Redundant Array of Independent Disks) Technology Large disk array comprising an arrangement of several independent disks Organized to improve reliability and increase performance Performance Increased through data striping Data segmented into equal-size partitions (striping unit) Transparently distributed across multiple disks Reliability Improved through storing redundant information across the disks using parity scheme or error-correcting scheme

RAID (Redundant Array of Independent Disks) Technology Different disk configurations aka RAID levels RAID 0 Nonredundant RAID 1 Mirrored RAID 0+1 Nonredundant and Mirrored RAID 2 Memory-Style Error-Correcting Codes RAID 3 Bit-Interleaved Parity RAID 4 Block-Interleaved Parity RAID 5 Block-Interleaved Distributed Parity RAID 6 P+Q Redundancy

DBMS and Web Security Internet communication relies on TCP/IP TCP/IP and HTTP not designed with security in mind Without special software, all Internet traffic travels ‘ in the clear ’ Anyone who monitors traffic can read it

DBMS and Web Security Must ensure while transmitting information over the Internet that: inaccessible to anyone but sender and receiver (privacy); not changed during transmission (integrity); receiver can be sure it came from sender (authenticity); sender can be sure receiver is genuine (non- fabrication); sender cannot deny he or she sent it (non- repudiation).

DBMS and Web Security Measures include: Proxy servers Firewalls Message digest algorithms and digital signatures Digital certificates Kerberos Secure sockets layer (SSL) and Secure HTTP (S-HTTP) Secure Electronic Transactions (SET) and Secure Transaction Technology (SST) Java security ActiveX security

How Secure Electronic Transactions (SET) Works

Chapter 19