Viruses! what are they? How are they different from worms?, How do they enter?, and how can one avoid them?. These are some questions which may arise in one's mind when they hear the word computer viruses.
Many may think that both viruses and worms are same. However there is small difference b/w them.
Virus is a program code that cannot work without being inserted into another program. On the other hand, a worm is a distinct program that can run unaided. Both of these can cause destructions, from displaying humorous messages to destroy contents of head disks etc.
1) melissa - designed to attack files on a single PC
2) CIH or chernobyl virus
3) W32/explorezip.worm-internet worm designed to infect PCs on n/w
- will delete .c,.cpp,.asm,.doc,.xls &.ppt files from local hard drives.
Attack of viruses has occurred many times in history. On August 18,2003 ,did a masked guest enter an internet newsgroup to infect his cyber companions with the widest-spreading and most costly e-mail virus of all time. Using a stolen credit card no, a guest opened an Easynews account and entered a newsgroup dedicated to pornography. Many of the guests clicked open an attachments, only to be infected. And so began Sobig.F, a virus that sent unsolicited e-mails. It disrupted businesses, effecting many.
How do they enter?
See,viruses enter through e-mails, file attachments like in the above case. Also when we borrow copies of software from others we are at risk of infecting our PC.Viruses copy itself to computers OS.
How to avoid them?
- In order to avoid virus risks, use the s/w after checking for viruses.
- Use antivirus programs like NORTON ANTIVIRUS,AVG etc
- If you receive email with subject line "imp msg from ----" be suspicious. If msg comes with word document attached called "list.doc", you have been likely been sent word/melissa macro virus or worm.
So keeping this in mind may help you avoid viruses.