Computer Virus Software For Small Businesses

Written by Helen Glenn Court
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Have you every considered that we take anti-virus software for granted? We invest in the programs--whether that means Symantec, McAfee, Avast, PC-cillin, or another solution. We configure computer and network settings to update virus definitions once a week or once a day or automatically. We respect viruses because we know the havoc they wreak--the operating systems they can compromise, the networks they can topple, and the data files they can corrupt.

At best they're an inconvenience. At worst they're disaster. When word gets around of a new scourge, we stop what we're doing to read about it. We have an idea of what viruses and worms do once they've infiltrated a system. We know they target either boot sectors or programs and program files. But we don't much care how the anti-virus programs do what they do, only that they do it.

How Anti-Virus Software Works

Viruses are programming code that executes and replicates itself on a computer without the user being aware. The virus itself needn't be actively destructive itself. It can, however, overwrite existing files or corrupt them, thus indirectly compromising the computer. The key to anti-virus software is detecting a virus, which is does by recognizing the signature code of the virus. There are four ways a virus can be detected.

Scanning--the most common--searches all files in memory against a list of all known signatures, with the advantage of being able to find a virus before it executes, and the disadvantage of depending on a signature. Interception warns about virus-like activity. Integrity checking is a relatively foolproof way of determining whether a file or program has been damaged, but works best when coupled with scanning. The fourth method is heuristic, that is, follows a set of rules to distinguish between viruses and regular files. Heuristic checking is potentially a gold mine, but as yet only potentially.

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