@Yuan Xue (yuan.xue@vanderbilt.edu) CS 285 Network Security Fall 2008.

@Yuan Xue (yuan.xue@vanderbilt.edu)

CS 285 Network Security

Fall 2008

@Yuan Xue (yuan.xue@vanderbilt.edu)

Course Information

When and Where Tuesday/Thursday 11am-12:15pm 209 Featheringill Hall

Instructor: Yuan Xue (yuan.xue@vanderbilt.edu) Office: 383 Jacobs Hall, Phone: 615-322-2926 Office hours: Monday/Thursday 2pm-3pm or by

appointment.

Web: http://vanets.vuse.vanderbilt.edu/~xue/cs285fall08/index.html

@Yuan Xue (yuan.xue@vanderbilt.edu)

Books and References

Textbook [WS] Cryptography and Network Security:

Principles and Practice (4th Edition) by William Stallings

Reference books [KPS] Network Security: Private Communication in

a Public World (2nd Edition), by Charlie Kaufman, Radia Perlman, Mike Speciner

[CSP] Security in Computing (3rd Edition), by Charles P. Pfleeger, Shari Lawrence Pfleeger

[MB] Computer Security: Art and Science, by Matthew A. Bishop

@Yuan Xue (yuan.xue@vanderbilt.edu)

Course Component

Lecture Slides + white board Take note Online digest/slides

Participation Discussion Presentation

Homework 5 assignments

MidtermProject

Grading Policy Participation:

10% Homework: 35% Midterm: 25% Project: 30%

@Yuan Xue (yuan.xue@vanderbilt.edu)

What you will learn from this course

What is “Security”?Where the security problems come from? Potential threats to a system

What are the solutions? Apply an appropriate mix of security measures

(protective, defensive, etc) Knowing what has worked, what has failed.

Security involves many aspects -Operating system, programming language, administration and policy

Our FocusNetwork Security

@Yuan Xue (yuan.xue@vanderbilt.edu)

Course Topics

Security Basics and Principles Symmetric/ Asymmetric Cryptography Basic concept, algorithm, mechanism, Design principles

Security Practices Secure protocols, systems and applications Hand-on experiences Secure network programming

Hot Topics and Recent Development Wireless security, DoS attack, etc.

@Yuan Xue (yuan.xue@vanderbilt.edu)

Survey and Feedback

Your input is important

Online Survey http://www.zoomerang.com/Survey/?p=WEB22873V62Y

WQ Feedback

@Yuan Xue (yuan.xue@vanderbilt.edu)

What is security?In general, security is the condition of being protected against danger or loss. (Wikipedia)In computer security and network security What are the subjects that need to be

protected?

Let’s start with some terms System

computer, network, application, data, resource Principal: an entity that participate in a

system user, person

@Yuan Xue (yuan.xue@vanderbilt.edu)

What is security?Computer Security Confidentiality means that only authorized

people or system can access the data or resource.

Integrity refers to the trustworthiness of data or resources. Data integrity means that data can only be modified

by authorized people or system in authorized ways Origin integrity means that the source of the data is

trustworthy, also called authentication. Message authentication means messages received

are exactly as sent (i.e. no modification, insertion, deletion, or replay), and the ID of the sender is valid.

Note: timing information Availability means that people has the ability to

use the information or resource desired.

@Yuan Xue (yuan.xue@vanderbilt.edu)

Where the security problem comes from?Let’s look at some example systems:

Bank Bookkeeping

Core operations customer account, journals recording the transactions

Who has the access to the information? Bank’s own staff – what if they cheat?

ATM Authenticate users based on card and ID number

Let’s go Internet The user – how do we know they are the “real” (authenticate)

user? Protect web servers and bookkeeping database

@Yuan Xue (yuan.xue@vanderbilt.edu)

Where the security problem comes from?

Hospital Patient record system

Who can access the record? – Many parties – insurance company, care giver, researcher,

etc Complicated -- role can change Privacy issue – HIPPA

Anonymize the record for research Is it sufficient?

Show me all records of 59-year-old males who were treated for a broken collarbone on September 15, 1966

Drug management Let’s go to Web

….

@Yuan Xue (yuan.xue@vanderbilt.edu)

Issues that will be addressed in this class

@Yuan Xue (yuan.xue@vanderbilt.edu)

Network Security IssuesFrom a Computer to Internet Single computer Networking environment

Secure communication in a public environment Computer system security with remote access

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Network Security

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

Read content of the messagefrom Bob to Alice

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

Modify content of the messagefrom Bob to Alice

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

capture the message from Bob to AliceAnd replay the message later

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

Pretend to be Bob tosend a message to Alice

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

Interrupt

@Yuan Xue (yuan.xue@vanderbilt.edu)

Some Simple Scenarios

Internet

Link

IP

TCP/UDP

Application

Link

IP

TCP/UDP

Application

Link

IP

Link

IP

Bob Alice

Darth

Observe message pattern

@Yuan Xue (yuan.xue@vanderbilt.edu)

What are the solutions?

@Yuan Xue (yuan.xue@vanderbilt.edu)

Why many solutions fail?

Protect wrong thingsProtect right things in the wrong way

@Yuan Xue (yuan.xue@vanderbilt.edu)

What are the solutions?

Security Basics and Principles Symmetric/ Asymmetric Cryptography Basic concept, algorithm, mechanism,

Security Practices Secure protocol designs Secure systems and applications

@Yuan Xue (yuan.xue@vanderbilt.edu)

How to study network security?

Principle of Easiest Penetration An intruder are expected to use any available

means of penetration. Computer security specialists must consider all

possible means of penetration.

Learning methodology examine all possible vulnerabilities of the system consider available countermeasures.