It is important to keep viruses in perspective. They are but one threat to your data and programs. they need not to be regarded as mysterious and they are quite easy to understand. Here are a few tips to keep in mind when considering viruses.
. you can only get virus by executing an infected program or booting from an infected CD plates. Any CD plate can be infected by boot sector virus, even non-bootable CD plates.
. you cannot get a virus simply by being on a bulletin board service (BBS), the internet or an online service, you will only become infected if you download an infected file and execute that file.
. Most viruses are transferred by booting from an infected CD plates (eg. stoned,form, antiExe etc. Remove CD plate from your A drive as soon as you are through with the CD plate. If your CMOS permits it, change your booting order to boot from your hard disk first. If you don’t know what CMOS is, check the manual for your computer ; there is normally an option when you boot your computer to hit a specific key to enter CMOS setup (eg. if its HP you are to press f10 and DELL press f2) this allows you to change many option on your computer.
. Make sure you have at least two backups for all of your files. Backups are essential not only to safely recover from virus infections, but also to recover from the other threats to your data.
. Be sure to check all new software for viruses. Even shrink wrapped software from a major publisher may contain a virus.
Computer viruses are a specific type of program written deliberately to cause harm to someone’s computer or to use that computer in an unauthorized way. There are many forms of malicious software viruses, but it’s important to understand the distinction between the various types.
Characteristics of viruses
viruses come in a great many different forms but they all potentially have two phases to their execution- the infection phase and the attack phase. When the viruses executes, it will infect other programs. what is often not clearly understood is precisely when it will infect the other programs. some viruses infect other programs each time they are executed, other viruses infect only upon a certain trigger. This trigger could be anything;
it could be a day or time, an external event on your computer, this is vital to the virus’s survival. if the virus infects too often, it is more likely to be discovered before it can spread far. Virus writers want their programs to spread as fast as possible before anyone detects them. so it is a serious mistake to execute a program a few times and find nothing and presume there are no viruses in the program. you can never be sure that the virus simply hasn’t triggered its infection phase.
Many viruses go resident in the memory of your computer just as a TSR(Terminate and stay Resident) program. This means the virus can wait for some external event such as inserting CD plate or readable flash drive, copying a file or executing a program can actually infect another program. This makes these viruses very dangerous since it has to guess what trigger condition they use for their infection. Resident viruses frequently corrupt the system software on the computer to hide their existence.
The second phase is the attack phase. many viruses do unpleasant things such as deleting files or changing random data on your disk, simulating types or merely slowing your computer down; some viruses do less harmful hings such as playing music or creating messages or animation on your screen. just as the virus infection phase can be triggered by some event, the attack phase also has its own trigger. Viruses usually delay revealing their presence by launching their attack only after they have had ample opportunity to spread. this means that the attack may be delayed for years after the initial infection.