1. Bazara Barry1 Security on Networks and Information Systems Bazara I. A. Barry Department of Computer Science – University of Khartoum www.itrc.sd/staff/bazara.html baazobarry@hotmail.com

2. Bazara Barry2 1 Introduction

3. Bazara Barry3 Outline Security trends The OSI security Architecture Security attacks Security services Security mechanisms A model for network security Internet standards and RFCs

4. Bazara Barry4 Security Trends (1-4) In 1994, the Internet Architecture Board (IAB) issued a report entitled "Security in the Internet Architecture". The report stated the general consensus that the Internet needs more and better security.

5. Bazara Barry5 Security Trends (2-4)

6. Bazara Barry6 Security Trends (3-4)

7. Bazara Barry7 Security Trends (4-4)

8. Bazara Barry8 The OSI Security Architecture The manager responsible for security needs some systematic way of defining the requirements for security and characterizing the approaches to satisfying those requirements. ITU-T Recommendation X.800, Security Architecture for OSI, defines such a systematic approach. The OSI security architecture focuses on security attacks, mechanisms, and services.

9. Bazara Barry9 Attacks, Services and Mechanisms Security Attack: Any action that compromises the security of information. Security Mechanism: A mechanism that is designed to detect, prevent, or recover from a security attack. Security Service: A service that enhances the security of data processing systems and information transfers. A security service makes use of one or more security mechanisms.

10. Bazara Barry10 Security Attacks

11. Bazara Barry11 Security Attacks

12. Bazara Barry12 Security Attacks Interruption: This is an attack on availability Interception: This is an attack on confidentiality Modification: This is an attack on integrity Fabrication: This is an attack on authenticity

13. Bazara Barry13 Security Goals Integrity Confidentiality Avalaibility

14. Bazara Barry14 Security Services Confidentiality (privacy) Authentication (who created or sent the data) Integrity (has not been altered) Non-repudiation (the order is final) Access control (prevent misuse of resources) Availability (permanence, non-erasure) – Denial of Service Attacks – Virus that deletes files

15. Bazara Barry15 Mechanism ServiceEncipherment Digital Signature Access Control Data Integrity Authentication Exchange Traffic Padding Routing ControlNotarization Peer entity authenticationYY Y Data origin authentication YY Access control Y ConfidentialityY Y Traffic flow confidentiality Y YY Data integrityYY Y Nonrepudiation Y Y Y Availability YY

16. Bazara Barry16 Security Mechanisms Specific security mechanisms (encipherment, digital signature, authentication exchange, traffic padding,…). Pervasive security mechanisms (trusted functionality, security label, event detection, security audit trail,…).

17. Bazara Barry17 A Model for Network Security (1-2)

18. Bazara Barry18 A Model for Network Security (2-2)

19. Bazara Barry19 Methods of Defense Encryption Software Controls (access limitations in a database, in operating system to protect each user from other users) Hardware Controls (smartcard) Policies (frequent changes of passwords) Physical Controls

20. Bazara Barry20 Internet standards and RFCs The Internet society –Internet Architecture Board (IAB) –Internet Engineering Task Force (IETF) –Internet Engineering Steering Group (IESG)

21. Bazara Barry21 Internet RFC Publication Process