Computer Virus

Computer virus is a self replicating piece of computer code that can partially or fully attach itself to computer files or application. Like any other program it contains instructions that tell your computer what to do. But unlike an application, a virus usually tells your computer to do something you don’t want it to do. Computer viruses are the common cold of modern technology. They can spread swiftly across open networks such as the internet, causing crores of rupees worth damage in a short span of time. If you are lucky, a virus will execute only a “personality quirk” such as causing your computer to make seemingly random bleeps. But some viruses can bee very destructive; they can format your hard drive, overwrite your hard drive boot sector, or delete files and render your machine inoperable. Five years ago, the chance you had receive a virus over a 12 month period was about 1 in 1000; today, your chances have dropped to about 1 to 10.

• Viruses enter your system via email, downloads, infected floppy disks, or hacking. By definition, a virus must be able to self replicate to spread.
• Thousands of viruses exist, but few are found roaming, unchecked, across networks.
• Virus behavior can ranger from annoying to destructive. Sometimes even relatively benign viruses tend to be destructive due to bugs introduced by sloppy programming.
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Antivirus software can detect nearly all types of known viruses, but it must be updated regularly to maintain effectiveness.

Symptoms of a virus attack

Some common symptoms of a virus attack are as follows:
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• The computer begins to run slowly.
• Unusual messages and graphics appear on your screen for inexplicable reasons.
• Music, not associated with any of the current programs, begins to play.
• Some of the program and or data files have either been corrupted or become difficult to locate.
• Unknown files or sub directories have been created.
• The size/ dates of executable files change automatically.
• The computer does not remember CMOS settings.
• The disk volume label has been changed mysteriously.
• The sizes of total and free memory are hanged unexpectedly
• The hardware devices begin to exhibit unusual behavior.

Antivirus Software

Virus experts have recorded more than 40,000 viruses and their variant strains over the years, though only about 200 of those viruses are actively spreading in the wild. While most viruses are just annoying time wasters, the ones that do deliver a destructive payload are a real threat.
Viruses have been around since the early 1960s, almost the same time when the early computers came into being. However, until the 1980s viruses were largely laboratory specimens, crated by researchers and released in a controlled environment to examine their effect. When viruses first appeared in the wild in the 1980s, they spread slowly and passed via the sneaker net”; floppy disks traded by people and shared between computers. Later on, widely available internet and email access hastened their spread. Two years ago, the advent of viruses that spread rapidly via email significantly increased the odds that an average computer user would confront a virus. E-mail viruses today account for about 80 percent of virus infections and can infect thousands of machines in a matter of minutes.

How did I get Virus, anyway?

You get a virus when you copy virus infected applications or files to your computer. The virus code inside the infected application or file gets activated when you run the application or open the file. How do you copy infected files is irrelevant: viruses don’t care if you get them as an email attachment, a download, or via a shared floppy disk. However, email attachments are the most prevalent and easiest mode of virus transmission. Once you open an infected file or application, the malicious code copies itself into a file on your system, where it waits to deliver its payload whatever programmer designed it to do to your system. Simply deleting the email after you open the attachment won’t get rid of the virus, since it has already entered the machine. A virus writer can set the payload to trigger immediately, at a present future time or date or upon the execution of a specific command, such as when you save or open a file.

Practice Safe Computing to Avoid Virus Attack

Prevention is always better than cure. While surfing the internet to protect the computer from virus attacks some preventive steps to be followed.

The best protection against a virus attack is to avoid opening unexpected email attachments and downloads from unreliable sources. Resist the urge to double-click everything in your mailbox. If you get an unexpected file attachment, send an enquiry email to its sender. Ask him about the nature and function of the file attachment.

For added safety, you need to install reliable antivirus scanning software and download its updates regularly. Major antivirus software venders, including Symantec, network associates, computer associates and trend micro, provide regular updates. Some venders also offers a service that will automatically retrieve updates on you computer from the company’s website.

Regular updates are essential. Researchers at computer economics estimate that 30 percent of small businesses are vulnerable to viruses because either they don’t keep their virus scanning software updated or they don’t install it correctly.

How anti virus software works

Scanning software installed in your system looks for a virus in two ways whether the virus is a known one or unknown. If it’s a known virus (one that has already been detected in the wild and has an antidote written for it), the software will look for the viruses signature – unique string of bytes that identifies the virus like fingerprint- and will remove it from your system. Most scanning software will catch not only a initial virus but also many of its variants as well, because the signature code usually remains intact.

In the case of new viruses for which no antidote has been created, the virus scanning software employs heuristics that look for unusual virus like activity on your system. If the program sees any suspected activity, it quarantines the questionable program and broadcasts a warning to you about what the program may be trying to do. Quarantine means keeping the virus in some isolated place on you computer under strict vigilance so that it could not do further harm to your computer. If you and the software think the program may be virus, you can send the quarantined file to the antivirus vendor, whereby researchers examine it, determine its signature, name and catalog it and release its antidote. It’s now a known virus. If the virus never appears again - which often happens when the virus are too poorly written to spread - then vendors categorize the virus as dormant. But viruses are like earthquakes: beacase initial out break is usually followed by aftershocks. Variants make up the bulk of known viruses.

You can easily purchase n anti virus software from the market or download a free version of some antivirus software from its company’s website. But it is recommended that you purchase a genuine copy of antivirus software as it comes with future support for your computer like updating the software against new virus threats and various additional features.