Making Things Clear…
According to Wikipedia, a virus is a self-replicating/self-reproducing-automation program that spreads by inserting copies of itself into other executable code or documents. A computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of a virus into the program is termed as an infection and the infected file (or executable code that is not part of a file) is called a host.
A virus has to be run before it can infect your computer. This means that they wait for user intervention, like double-clicking the infected file, before executing.
The term spyware refers to a broad category of malicious software designed to intercept or take partial control of a computer’s operation without the informed consent of that machine’s owner or legitimate user. While the term taken literally suggests software that surreptitiously monitors the user, it has come to refer more broadly to software that subverts the computer’s operation for the benefit of a third party, usually advertisers.
Spyware differs from viruses and worms in that it does not usually self-replicate. Like many recent viruses, however, spyware – by design – exploits infected computers for commercial gain. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements; theft of personal information (including financial information such as credit card numbers); monitoring of Web-browsing activity for marketing purposes; or routing of HTTP requests to advertising sites.
What do they do?
1. Delete data – Worms like Sircam or Nyxem attempts to delete or overwrite data on a specified date.
2. Corrupt data – Some computer viruses tend to change data on certain office application.
3. Play pranks – Me.Exe copies itself from one floppy to another and resides to the computer system. It makes the floppy drive active even there is no diskette inserted which damages the drive after a period of time.
4. Steal data – The Bugbear-D records the users’ keystrokes, including passwords, and gives the virus writer access to them.
5. Let other users hijack your computer – A hijacked computer system refers to a system that is taken control by another user via the network or the web.
6. Slow down your computer – Viruses run on the background unnoticed by the users. These viruses utilize computer resources like memory or CPU making your computer function at a snail’s pace.
7. Make your system unstable – Other computer viruses that go with spywares, disable ports that prevent you from opening webpages.
8. Make the network run slow – Sometimes your internet connection would run slow. Others blame the network topology or even applications/softwares that were included in the network system. But one of the main reasons is that there are present spywares and viruses residing in some computer units and these would creep inside the network and look for other possible host targets. Sometimes they use your bandwidth just to download other softwares and the like.
What should we do?
1. Install and update anti-virus and anti-spyware utilities – An anti-virus doesn’t detect spywares and anti-spywares don’t detect viruses. It’s better if you have both installed in your system. There are companies that offer free versions of their anti-virus and anti-spyware. There’s AVG and Avira for anti-virus and Lavasoft Ad Aware for anti-spyware. There are free anti-virus also like PC Tools Anti-Virus and ClamWin. PC Tools Spyware Doctor is a free antispyware also.
2. Do not click pop-ups – Pop-ups are those annoying windows that pop whenever we visit or open certain websites. They advertise products, like screensavers, smilies or cursors, or make warnings about the presence of computer threats. DO NOT CLICK THEM! Close the window by clicking the X button on the top-right corner. They themselves are spywares. Installing them would just create problems.
3. Be extra careful with e-mail attachments – If you receive an e-mail with attachments, scrutinize it first. Do you know who sent you that attachment? Were you asking for a certain file from someone? Or were you informed by someone that they will be sending you a file? Check also the extension name of the file. Extension names are strings of characters beginning with a period and followed by one to three letters. Examples are .doc, .xls, .ppt, etc. If you receive a file with an extension name like .bhx, .pif, .vbs or those that are unknown to you or not related to your field, delete them right away. Another is, if you receive attachments with double extension names like filename.pif.vbs, move the e-mail to the trash folder. It’s a possible virus-infected attachment.
4. Know your files and their extension names – Sometimes viruses would disguise themselves using icons and would look like a normal windows or office file like a Microsoft document or even a folder. If you found a new file in your My Documents folder or the Desktop, check its extension name. You can also check a file’s type by right-clicking the file and selecting Properties. Check the Type of File field. If you are trying to inspect a Microsoft office file like Word, or Excel, and found that its Type of File is Application, delete the file. It’s a virus.
5. Be updated and be aware – Prevention is always better than cure. Keep yourself updated with the latest IT news. Know the threats and know how to avoid them.