itc chapter # 11

COMPUTER & DATA SECURITY

Introduction to ComputingCHAPTER #

11

Introduction to Computing 2Chapter # 11

Security

Security is about the protection of assets It can be computer, network or data security

Security is a set of procedures that protect You, your employees, and your peers

Paper or electronic media

Hardware, software, and networks

It protects from damage, theft, or change There can be different security measures

Prevention measures taken to protect your assets from being damaged

Detection measures taken to allow you to detect when an asset has been damaged,

how it was damaged and who damaged it

Reaction measures that allow you to recover your assets


Computer Security

Computer security is information security as applied to computers and networks

The field covers all the processes and mechanisms by which computer-based equipment, information, networks and services are protected from unintended or unauthorized access, change or destruction

It also includes protection from unplanned events and natural disasters


Security Properties

Confidentiality ensures that the data is only read by the intended recipients

Integrity ensures that all of the data has not been corrupted from its

original source

The system continues to operate properly.

Availability Actions by an attacker do not prevent users from having access

to use of the system

guarantees that the data is usable upon demand

Accountability it is audit information that is kept and protected so that security

actions can be traced to the responsible party


Highly Vulnerable

Financial institutions and banks

Internet service providers

Government and defense agencies

Multinational corporations

Pharmaceutical companies

Contractors to various government agencies

Anyone on the Internet


Types of Attacks

Denial of Service (D.o.S) attacks

D.o.S attacks have one goal – to knock your service off the net

Crash your host

Flood your host

Flood the network connecting to your host

Viruses

A computer virus attaches itself to files on the target machine

Master Boot Sector/Boot Sector viruses

File viruses, Macro viruses

Stealth viruses, Polymorphic viruses


Types of Attacks

Trojans Trojans are programs that appear to perform a desirable and necessary

function that perform functions unknown to (and probably unwanted by) the user

Worms Worms are memory resident viruses

Unlike a virus, which seeds itself in the computer's hard disk or file system, a worm will only maintain a functional copy of itself in active memory

Worms frequently “sleep” until some event triggers their activity e.g. send password file to hacker, send copy of registry to hacker

Worms and Trojans are frequent methods by which Backdoors are enabled on a system

Backdoors Such programs give remote access to the computer from anywhere on

the Internet

e.g. Back Orifice, BO2K, Sub-Seven)


Types of Attacks

Sniffers

Devices that capture network packets

Extremely difficult to detect because they are passive

Scanners

Programs that automatically detect security weaknesses in remote or local hosts

Tells the hacker

What services are currently running

What users own those services

Whether anonymous logins are supported

Whether certain network services require authentication

Password Crackers

Some actually try to decrypt

Most simply try “brute force” or intelligent “brute force”

Dictionary words, days of year, initials


Types of Attacks

Social Engineering

“This is MIS, I can fix your e-mail box, what’s your password?”

Email Spoofing

It tricks the user in believing that the email originated from a certain user such as an administrator although it actually originated from a hacker

Such emails may solicit personal information such as credit card details and passwords

Examining the email header may provide some additional information about the origin of the email


How Do We Protect

Anti-virus software

Personal Anti-virus SW on your machine

Make sure it is set to scan all executables, compressed files, e-mail, e-mail attachments, web pages

Keep your virus information files up to date!!!

Firewalls A combination of hardware and software resources positioned

between the local (trusted) network and [an untrusted network]

It ensures that all communication between an organization's network and the Internet connection conforms to the organization's security policy

It tracks and controls communications, deciding whether to pass, reject, encrypt, or log communications


Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties

Modern cryptography intersects the disciplines of mathematics, computer science, and electrical engineering

Applications of cryptography include ATM cards, computer passwords, and electronic commerce

Simply – secret codes

Encryption Converting data to unreadable codes to prevent anyone form accessing this

information

Need a “key” to find the original data keys take a few million-trillion years to guess

Public keys An ingenious system of proving you know your password without disclosing your

password. Also used for digital signatures

Used heavily in SSL connections

Hashing Creating fingerprints of documents


Cryptography

Symmetric encryption

Authentication

Asymmetric encryption

Public Key Infrastructure


Steganography

Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message

It is a form of security through obscurity

Message appears to be something else

images, articles, shopping lists, or some other cover-text

Classically, the hidden message may be in invisible ink between the visible lines of a private letter

Messages do not attract attention to themselves

It is high security technique for long data transmission


Watermarking

Watermarking is the process of hiding digital information in a carrier signal

It is a technique in which a kind of marker is embedded in a signal such as audio or image data

Used to identify ownership of the copyright of such signal

Digital watermarks may be used to verify the authenticity or integrity of the carrier signal or to show the identity of its owners

It is prominently used for tracing copyright infringements and for banknote authentication

itc chapter # 11

Education