1. Network Security

2. Introduction to Networking What is Network ? The ISO/OSI Reference Model - The International Standards Organization (ISO) Open Systems Interconnect (OSI) What are some popular Networks ? UUCP(unix-to-unix copy) -Batch-oriented Processing -Implementation Environment

3. -Popularity -Security Internet What is the Internet ?

4. Network History In 1969, the Defense Advanced Research Projects Agency(DARPA) solicited the efforts of four computer institutions to design a network through which data could be passed and received. UCLA, the University of California at Santa Barbara, the University of Utah, and the SRI collaborated to bring forth the birth of the Internet. Apple computer released the first Personal Computer in early 1980s. By late 1980s, the PC market and Local Area Networks were growing larger than had ever been conceived possible.

5. The Language of the Internet Open Design IP(Internet Protocol) - Understanding IP - Attacks Against IP TCP(Transport Layer Protocol) - Guaranteed Packet Delivery IETF(Internet Engineering Task Force)

6. UDP(User Datagram Protocol) - Lower Overhead than TCP One of the things that makes UDP nice is its simplicity. Because it doesn't need to keep track of the sequence of packets, whether they ever made it to their destination, etc., it has lower overhead than TCP. This is another reason why it's more suited to streaming-data applications: there's less screwing around that needs to be done with making sure all the packets are there, in the right order, and that sort of thing.

7. Risk Management : Game of Security Can’t say “what’s the best Firewall?” There are two extremes: absolute security, absolute access Every organization needs to decide for itself where between the two extremes of total security and total access they need to be. A policy to articulate this, and then define how that will be enforced with practices and such. Everything that is done in the name of security, then, must enforce that policy uniformly.

8. Types And Sources of Network Threats Denial-of-Service - Nastiest, and most difficult to address -easy to launch, difficult track Unauthorized Access - Executing Commands illicitly - Normal user access - administrator access -Confidentiality Breaches - What is it that you are trying to protect yourself against ?

9. -Destructive Behavior -Two major categories 1. Data Diddling 2. Data Destruction

10. Where Do They Come From ? Lessons Learned - H ope you have backups - Don’t put data where it doesn’t need to be - Avoid systems with single points of failure - Stay current with relevant operating system patches - Watch for relevant security advisories - Have someone on staff be familiar with security practices

11. Firewalls -Bastion host -Router -Access Control List(ACL) -Demilitarized Zone(DMZ) -Proxy Types of Firewalls 1. Application Gateways - Runs at application layer. Traditionally, these have been most secure, because they don’t allow anything to pass by default - Typically slowest, because more more processes need to be started

12. 2. Packet Filtering 3. Hybrid Systems -access control perform at lower ISO/OSI level -it is a technique Where by routers have ACLs (Access Control Lists) turned on. -In an attempt to marry the security of the application layer gateways with the flexibility and speed of packet filtering,some vendors have created systems that use the principles of both.

13. So,What’s best for me ? -Lots of Options are available Some Words of Caution - Single Points of Failure Many ``firewalls'' are sold as a single component: a bastion host, or some other black box that you plug your networks into and get a warm-fuzzy, feeling safe and secure. The term ``firewall'' refers to a number of components that collectively provide the security of the system. Any time there is only one component paying attention to what's going on between the internal and external networks, an attacker has only one thing to break (or fool!) in order to gain complete access to your internal networks.

14. Secure Network Devices Secure Modems ;Dial-back Systems Crypto-Capable Routers Virtual Private Networks

15. Host-based Intrution Detection Audit Policy Management and Centralization Monitor,Detect, and Respond to User and System Activity and Attacks Data Forensics,Statistical Analysis and Evidentiary Support Access Control

16. References 1 http://rr.sans.org/ 2 http://cert.org/http://cert.org/ 3 www.ciol.com 4 http://securitypointer.com 5 J.P. Holbrook, J.K. Reynolds. ``Site Security Handbook.'' RFC 1244.``Site Security Handbook.'' 6 M. Curtin, ``Snake Oil Warning Signs: Encryption Software to Avoid.''``Snake Oil Warning Signs: Encryption Software to Avoid.''