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Downloading + Viruses. Downloading Modems (56K) V.90 DSL (digital subscriber line) Cable Modem Satellite.

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Presentation on theme: "Downloading + Viruses. Downloading Modems (56K) V.90 DSL (digital subscriber line) Cable Modem Satellite."— Presentation transcript:

1 Downloading + Viruses

2 Downloading Modems (56K) V.90 DSL (digital subscriber line) Cable Modem Satellite

3 Downloads Music Movies Books Applications Photos/Images Text Files Server vs. Peer to Peer

4 Cost of Downloaded Programs Freeware Drivers, etc. Shareware Trial Purchased Programs

5 ftp Sites Upload and download files on the internet. Greatly replaced by web files downloads. FTP sites accessed through a browser for downloads: ( FTP software can work with a command line or graphic interface.

6 Downloading Plug-Ins Flash ( Quicktime RealPlayer Shockwave Acrobat Reader VRML

7 Viruses A program which infects (affects) other programs or sectors of a disk or hard drive. Transmitted with an infected disk, program or file. An e-mail virus is transmitted by opening an “executable” attachment received via e-mail A virus can attack the BIOS, erase files, erase the hard drive, or simply reveal messages Some types: polymorphic, stealth “in the wild”

8 Types of Viruses Harmless Paper-tigers Harmful Hot Famous viruses include: Michelangelo ('Michel angelo'_computer_virus), Melissa, Loveletter'Michel angelo'_computer_virus

9 Worms Many viruses are actually worms. Transmitted over network (internet) if there is a security hole. (Windows vs. Macs and Unix) Frequently spreads by copying e-mail addresses from address books. May be “harmless” (just take up processing time) or ruin files or erase hard drives. Always replicate themselves to spread. Robert Morris story—disconnect computer when experimenting

10 Mydoom Virus Causing problems in January 2004 Attacking companies, including Microsoft Moves through e-mail (as a Technical Message) and if opened, may reprogram your computer into a “zombie” (a computer which attacks other sites), replicates by sending to addresses in address book, and/or connects to Kazaa and disguises itself as a bootleg copy of Microsoft Office living on your computer.

11 Trojan Horses Programs hidden within other programs (have two simultaneous functions). Cause damage to files or a hard drive or create some frivolous effect: an annoying greeting. If one program is indeed useful, malicious purpose is never discovered.

12 Spyware Keylogger Information may be sent to chat room or other “public” place May be hidden in “Adware”

13 Programs to Fight Viruses Scanners Monitors Integrity Checkers Immunizers Behavior Blockers

14 Avoiding Viruses Update antivirus program Be careful with attachments Install program updates Check disks and other “mobile media” Back up files Create a virus-free startup disk Use multiple techniques

15 Other Methods of Affecting Your Computer Remote-access software Web Sites (possibly with Active X)

16 How Hackers Find You Must discover your IP address This happens when you: Visit the hacker’s site Visit a site that has been “hijacked” Open an e-mail with HTML that connects to the hacker’s site. Send an e-mail to the hacker’s site Post to a newsgroup A virus that “phones home” Share an ISP/LAN Or…War Dialing

17 Hackers also… Find holes in popular programs e.g. AOL Instant Messenger Look at your hard drive Clean-Up Afterwards?

18 Other malevolent approaches Cookies: used by multiple sites E-Mail hoaxes: (they are the viruses) or e-mail directions to erase a file Website Hosts, including redirection (

19 Protective Measures Use virus programs. Add a firewall, especially if you have a high-speed connection. Own a Macintosh (or Unix) computer. Supposedly safe attachments: txt; jpg, gif, bmp, tif,wmf; avi,mpg,mov,wmv;pdf;mp3,wav Possibly unsafe attachments: bat,com,exe,js,jde,pif,reg,scr,shs,vbe,vbs, wsf,wsh Be wary of Peer-to-Peer, remote access applications, public wireless systems, as well as personal web servers Choose good passwords

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