Computer Security Chapter 8

7/31/2019 Computer Security Chapter 8

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Computer SecurityStd XIChapter 8


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Security Principles

During

Data Transmission on theInternet


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Confidentiality

Content of the message

should be accessed by Sender &

Recipient


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Integrity

Message/data must arrive

exactly as it was sent

NO modification done either

accidentally or maliciously


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Authentication

Receiver must be sure of thesenders identity

All users must have a

user ID &

password


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Nonrepudiation

A sender must not denyhaving sent the message to

the receiver


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For security

Encryption and Decryptionare used.


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Destructive software Viruses

Malware

Spyware

Worms

Browser Hijackers Spam


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Viruses

Vital Information

Resources Under

Seize


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Viruses

Cannotaffect

hardware

Attacks

software

such asO.S.

application

softwaree-mails

data


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Types ofViruses

Boot sector virus

Macro virus

E-mail virus

File infector virus (.com,.exe, .sys, .ovl, .prg, .mnu)


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How the virus works

Clean uninfectedprogram

Virus Infectedprogram

Compute A , B

Perform printing

End

Compute A , B

Delete all files

Corrupt data

Send copy of virus

to all programs

Perform printing

End


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Malware & Spyware

performs malicious action w/o

users permission

Spyware gathers information

relays info to advertisers & others

installed w/o consent, knowledge(click, pop-up) (adware)


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Worms

Replicateyourself

Replicate

yourself

Replicateyourself

Replicate

yourself

Replicate

yourself

Replicate

yourself

Replicate

yourself

Replicate

yourself

Replicate

yourself

Replicate

yourself

No destruction

Eat up

Computersresources

Make the

computer

unusable


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Trojan Horse Is not self replicatingmain purpose is not make

modifications in the target computer

Requires interaction with the hacker

Reveals confidential info (user ID,

pwd)Allows hackers remote access to

target system


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Browser Hijackers alters your browser settings redirects home page to rogue search

engines

With sponsored links as results (hit list)

Could also direct the browser to an

error pageForces hits


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Spam abuse of e-mail unsolicited mail, bulk e-mail (UBE)

Commercial content

Use of spam guard

Spammers collect e-mail addresses

from chatrooms, websites, customer lists,newsgroups, and viruses which harvest

users' address books,


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Antivirus

protection from virus,

worm, trojan horse, malware can be purchased or

downloaded


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Commercial Antivirus

softwareAVG

BitDefender

Norton

McAfee

KasperskyeScan

K7

Bull Guard

Dr.Web

Panda Security

PC Tools

Protector PlusRising

ZoneAlarm


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Freely available Antivirus

softwareAOL ActiveVirus Shield

AVG AntivirusFree Avast Home

Bitdefender 8

free edition

Comodo

McAfee

VirusScan Plus

PC Tools AntiVirusFree Edition

Dr.Web Cureit!


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Antivirus software

downloadsClamClamWin

Moon Secure

Open

WinpoochAbandonware

Aidstest

Antiviral Toolkit

Pro

Central PointdLight

Dr. Solomons

The Antidote

Thunderbyte

Turbo


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Preventive MeasuresDo not open e-mail attachmentsUpdate anti-virus software regularly

Delete chain letters, forward, virus

alerts and junk mail

When Downloading files if unsure of

their authenticity, scan them firstBackup regularly

Do not hide file extensions


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Preventive Measures

Do not download files from strangers

If you have to then download to a

removable disk and scan with antivirus

Protect using Internet firewall


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To Turn on Firewall

Click start

Control Panel

Security Center

Windows firewall


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For Unhiding File

Extensions Click My Computer

Tools Menu Folder Options

View tab

Uncheck Hide extensions

for known file types


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Lab Exercise Find names of Trojan Horses

Find names of Viruses

Find names of Worms Find details of Malware

Find details of spyware

Find names of Browser Hijackers

Anti Virus scanning procedure

details

Computer Security Chapter 8

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