Viruses and Spyware


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Viruses and Spyware

  2. 2. Types of Electronic Infection <ul><li>When you listen to the news, you hear about many different forms of electronic infection. The most common are: </li></ul><ul><li>Viruses - A virus is a small piece of software that piggybacks on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, </li></ul><ul><li>Worms - A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well. </li></ul><ul><li>Trojan horses - A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically. </li></ul><ul><li>Ad ware / Spy ware - legal programs which download to your computer attached to websites. Although mostly harmless, these display annoying pop-up ads, and may slow down your computer by logging your keystrokes to report back to the advertising companies. </li></ul><ul><li>Email spam – Advertising and “junk mail” which is mailed in bulk by advertising companies or by spiteful individuals. These emails usually do no more than clog up your in-box with unwanted and often offensive emails. </li></ul>
  3. 3. Viruses <ul><li>Most viruses move around in e-mail messages. A virus usually replicates itself by automatically mailing itself to dozens of people in the victim's e-mail address book. You can also get a virus from using a floppy that has been infected, or from downloading an infected file from the internet. </li></ul><ul><li>Some viruses are programmed specifically to damage the data on your computer by corrupting programs, deleting files, or erasing your entire hard disk. </li></ul><ul><li>All computer viruses are manmade. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the computer system to a halt. </li></ul><ul><li>Many computer viruses turn out to be hoaxes or myths. For a list of hoaxes check out Computer Virus Myths . </li></ul>
  4. 4. DEFENSE !! <ul><li>Before downloading or opening any email attachment be sure you know what it is. </li></ul><ul><li>If the e-mail is from an address that you don’t recognize, delete it without opening it!! </li></ul><ul><li>If it is from someone you know, but were not expecting an attachment, check with that person to make sure they really did send it. Viruses can appear to be sent from people you know because the virus attacks a person’s computerized address book. </li></ul>
  5. 5. Worms <ul><li>A worm is a computer program that replicates itself and is self-propagating. While viruses are designed to cause problems on a local system and are passed through boot sectors of disks and through files, worms are designed to thrive in network environments. A worm almost always does something malicious, such as consuming computer resources and freezing up processes. Network worms were first defined by Shoch & Hupp of Xerox in ACM Communications (March 1982). The most famous (or infamous) worm was the Internet Worm of November 1988. It successfully propagated itself on over 6,000 systems across the Internet. </li></ul>Defense: the only good defense against worms is up to date Anti Virus software.
  6. 6. Trojan Horse <ul><li>A Trojan horse is a destructive program that masquerades as a benign application. Like the legendary wooden horse, it is much more than it appears. A program might look like a game, but instead may log your keystrokes and steal your personal information. </li></ul><ul><li>Unlike a virus, a Trojan horse does not replicate itself but can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid your computer of viruses but instead introduces viruses onto your computer. </li></ul>Defense : Be very selective about the games and other nifty programs that you download. Also be sure to be running a good Anti-Virus software.
  7. 7. DEFENSE: Anti Virus Software <ul><li>There are quite a few great anti-virus programs available. Two of the most popular are Symantec and McAfee </li></ul><ul><li>These companies constantly monitor the Internet for newly created viruses and threats. Their teams of expert programmers then quickly design programs which counterattack and eliminate these new threats. </li></ul><ul><li>When you install the software, you purchase the rights to keep downloading the updates that will protect you from the most recently discovered threats. </li></ul><ul><li>A common mistake that consumers make is to think that they are protected simply by installing the anti-virus software. It is crucial that the updates are downloaded on a regular basis. </li></ul><ul><li>Please check with your parents to make sure that they are keeping your home anti-virus software up to date. </li></ul>
  8. 8. Adware or advertising-supported software <ul><li>Adware is any software application in which advertisements are displayed while the program is running. These applications include additional code that displays the ads in pop-up windows or through a bar that appears on a computer screen. Adware helps recover programming development costs, and helps to hold down the price of the application for the user (even making it free of charge)—and, of course, it can give programmers a profit, which helps to motivate them to write, maintain, and upgrade valuable software. </li></ul>
  9. 9. Spyware <ul><li>Spyware closely resembles but clearly differs from viruses. In both cases, the program installs without the user's knowledge or consent. In both cases, system instability commonly results. Spyware generally does not self-replicate. </li></ul><ul><li>Most spyware installs itself in such a way that it starts up every time the computer starts up and runs at all times, logging keystrokes, monitoring Internet usage and delivering targeted advertising to the infected system. Spyware generally does not damage the user's data files, but if it is logging keystrokes (sending the information on everything that you type back to the ad company) you may notice that your computer is suddenly running really slow. </li></ul>
  10. 10. Defense against Adware and Spyware If you are noticing a lot of pop-ups, or if your computer is suddenly running very slow, you can download a free program called Ad-Aware for at This program scans your system for hiding places where these advertising companies save their programs. Like the anti-virus software, this program must also be updated before you scan with it each time. This will ensure that you are getting the most recently developed protection.
  11. 11. E-mail spam <ul><li>Spamming is unsolicited commercial e-mail. Because of the very low cost of sending e-mail, spammers can send hundreds of millions of e-mail messages each day over an inexpensive Internet connection. Hundreds of active spammers sending this volume of mail results in many computer users receiving tens or even hundreds of junk e-mails each day. Spammers gather e-mail addresses in a variety of ways. One of these is by using a spambot—a program that gathers e-mails from web pages and uses them as targets for spam. </li></ul><ul><li>Spam may also contain an embedded image (or ‘Web bug’), which you may not even be able to see, It is often a single, transparent pixel, but it allows spammers to know that you are opening your email. The image is actually on their web site, and opening the email activates the link to that image, telling the spammer’s computer that you actually look at your spam, so send more! </li></ul><ul><li>Many e-mail spammers go to great lengths to conceal the origin of their messages. The spammer modifies the e-mail message so it looks like it is coming from another e-mail address. </li></ul>
  12. 12. <ul><li>  </li></ul><ul><li>How to recognize Spam without opening your e-mail: </li></ul><ul><ul><li>Garbage at the end of the Subject: line </li></ul></ul><ul><ul><li>No real name or no spaces in the From: line </li></ul></ul><ul><li>Simple Ways to Avoid Getting Spam </li></ul><ul><li>Never respond to spam </li></ul><ul><ul><li>Never buy a product advertised in spam </li></ul></ul><ul><ul><li>Do not give your e-mail address without knowing how it will be used </li></ul></ul><ul><ul><li>Use a 2nd e-mail address for distribution lists or discussion groups </li></ul></ul><ul><ul><li>Use e-mail filters and junk mail controls built into your e-mail software </li></ul></ul>Defense