1. Overview of Network Security

2. Network Security2 New Challenges 1.Security does not focus on a “product” only; it is a process and focuses on the whole “information system”. 2.Scalability demands are increasing. –Any one of the hosts may be compromised … 3.Providing legacy endpoint security becomes expensive. 4.Day zero attacks T. A. Yang

3. Network Security3 Principles of Security The CIA Model (aka. CIA triad) –Confidentiality prevents unauthorized disclosure of sensitive information. –Integrity prevents unauthorized modification of data. –Availability is the prevention of loss of access to resources and information to ensure that information is available for use when it is needed. T. A. Yang

4. Network Security4 Security Model A security model is a multilayered framework made of many integrated entities and logical and physical protection mechanisms, all working together to provide a secure system that complies with industry best practices and regulations. Strategic (what) level: –A security policy is a set of rules, practices, and procedures dictating how sensitive information is managed, protected, and distributed. –Standards are industry-recognized best practices, frameworks, and agreed principles of concepts and designs, designed to implement, achieve, and maintain the required levels of processes and procedures. Tactic (how) level: –Procedures are low-level documents providing systematic instructions on how the security policy and the standards are to be implemented. –A baseline is the minimum level of security requirement in a system. –Guidelines are recommended actions and operational guides for users. T. A. Yang

5. Network Security5 Perimeter Security? Its meaning has become increasing uncertain. –Geographic boundaries? –Inside vs outside? Wireless connections, VPN connections –Remote access? –Single point of entrance vs multi-entry open environments  multi-perimeter, multi-layered networks T. A. Yang

6. Network Security6 Multilayer Perimeter Solution The principle of defense in depth Security is applied across all layers of the system. Firewalls are not only between the public and the private network, but also between different zones of the private network. Intrusion monitoring/prevention is applied to both the inside and the outside boundaries of the private network. T. A. Yang

7. Network Security7 The Domino Effect The layered approach in the OSI reference model was developed to accommodate changes in the evolving technology. Information flows up and down to the next subsequent layer as data is processed. Implication: If one layer is hacked, communications are compromised without the other layers being aware of the problem. “A chain is as strong as the weakest link.” T. A. Yang

8. Network Security8 The Security Wheel An ongoing process to ensure system security: Develop a security polity  Make the network secure  Monitor and respond  Test  Manage and improve  … T. A. Yang