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Basic Security Concepts

• What is a threats?– Anything that can harm a computer– Vulnerabilities are weaknesses in security– Security attempts to neutralize threats

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Basic Security Concepts

• Degrees of harm– Level of potential damage– Include all parts of system

• Potential data loss• Loss of privacy• Inability to use hardware• Inability to use software

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Basic Security Concepts

• Countermeasures– Steps taken to block a threat– Protect the data from theft– Protect the system from theft

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Threats To Users

• 1. Loss of privacy– Personal information is stored electronically– Purchases are stored in a database

• Data is sold to other companies

– Public records on the Internet– Internet use is monitored and logged– None of these techniques are illegal

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Threats to Users

• 2. Cookies– A cookie is information that a Web site puts

on your hard disk so that it can remember something about you at a later time.

– Cookies now track history and passwords– Browsers include cookie blocking tools

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Threats to Users

• 3. Spyware– Software downloaded to a computer– Designed to record personal information– Typically undesired software– Hides from users– Several programs exist to eliminate

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Threats to Users

• 4. Web bugs– Small programs embedded in gif images– A Web bug, also known as a Web beacon,

is a file object (usually a graphic image such as a transparent GIF) that is placed on a Web page or in an e-mail message to monitor user behavior.

– Gets around cookie blocking tools– Companies use to track usage

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Threats to Users

• 5. Spam– Unsolicited commercial email– Irrelevant or unsolicited messages sent

over the Internet, typically to large numbers of users, for the purposes of advertising, phishing, spreading malware, etc.

– Networks and PCs need a spam blocker• Stop spam before reaching the inbox

– Spammers acquire addresses using many methods

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Threats to Data

• The most serious threat– Data is the reason for computers– Data is very difficult to replace– Protection is difficult

• Data is intangible

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Threats to Data

• Viruses– Software that distributes and installs itself– Ranges from annoying to catastrophic– Countermeasures

• Anti-virus software• Popup blockers• Do not open unknown email

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Threats to Data

• Trojan horses– Program that poses as beneficial software– Not an actual virus but a loophole to cause

virus.– User willingly installs the software– Countermeasures

• Anti-virus software• Spyware blocker

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Threats to Data• Cybercrime

– Using a computer in an illegal act– Fraud and theft are common acts

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Threats to Data

• Internet fraud– Most common cybercrime– Fraudulent website– Have names similar to legitimate sites

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Threats to Data

• Hacking– Using a computer to enter another network– Cost users $1.3 trillion in 2003– Hackers motivation

• Recreational hacking• Financial hackers• Grudge hacking

– Hacking methods• Sniffing• Social engineering• Spoofing

Computer virus

• Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation.

• A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk.

• Computer viruses are often spread by attachments in e-mail messages or instant messaging messages

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Causes of Computer virus

• Virus infection in computers can be caused through different means. Below are the commonest causes of Computer Virus attack.Through the internetThrough email attachmentThrough removable storage devicesThrough Bluetooth transfer

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Most Common Types of Viruses

• 1. Resident Viruses

• This type of virus is a permanent which resides in the RAM memory. From there it can overcome and interrupt all of the operations executed by the system: corrupting files and programs that are opened, closed, copied, renamed etc.

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2. Boot Virus• This type of virus affects the boot sector of a floppy or

hard disk. This is a crucial part of a disk, in which information on the disk itself is stored together with a program that makes it possible to boot (start) the computer from the disk.

The best way of avoiding boot viruses is to ensure that floppy disks are write-protected and never start your computer with an unknown floppy disk in the disk drive.

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3. Overwrite Viruses• Virus of this kind is characterized by the fact that it

deletes the information contained in the files that it infects, rendering them partially or totally useless once they have been infected.

The only way to clean a file infected by an overwrite virus is to delete the file completely, thus losing the original content.

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4. Directory Virus• Directory viruses change the paths that indicate the

location of a file. By executing a program (file with the extension .EXE or .COM) which has been infected by a virus, you are unknowingly running the virus program, while the original file and program have been previously moved by the virus.

Once infected it becomes impossible to locate the original files.

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5. File infectors•

This type of virus infects programs or executable files (files with an .EXE or .COM extension). When one of these programs is run, directly or indirectly, the virus is activated, producing the damaging effects it is programmed to carry out. The majority of existing viruses belongs to this category, and can be classified depending on the actions that they carry out.

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Antivirus

• Anti-virus software is a program or set of programs that are designed to prevent, search for, detect, and remove software viruses, and other malicious software infections like worms, Trojans and more.

• McAfee

• ESET NOD32

• Avast

• Avira

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Functions of Antivirus• Scan specific files or directories for any malware or

known malicious patterns• Allow you to schedule scans to automatically run for

you• Allow you to initiate a scan of a specific file or of your

computer, or of a CD or flash drive at any time.• Remove any malicious code detected –sometimes

you will be notified of an infection and asked if you want to clean the file, other programs will automatically do this behind the scenes.

• Show you the ‘health’ of your computer

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PASSWORD• Password is a secret word that is used to protect a

computer system or program. It may consist of numbers, alphabets or both. The user has to type the password to access the computer system.

• Examples:-Every computer provides an option for setting password. If the computer is protected with password, it will ask for that password to login.

Email facility on the internet is also protected with password. Every user has to give email ID and password to check emails.

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Purpose of password

• The purpose of password is to protect data stored on a computer.

• It protects data from being lost, misused or deleted by any person.

• The system can be accessed by a person who knows the password.

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Tricks for obtaining password

• There are two essential password rules to consider when creating a password for the first time

• – length and complexity.• Your password length should be at least 8

characters long • Your password should use a combination of

lower case letters, upper case letters, numbers, and special characters

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Purpose of password

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Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

McGraw-Hill Technology Education

Chapter 14A

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