Computer Viruses and Security

Malicious software, often called malware, is any program written to harm a computer, steal information or spread without the owner’s consent. The term computer virus originally referred to a specific kind of malware that attaches itself to a file or program and copies itself into others when that file is run, much as a biological virus spreads. Over time the word came to be used loosely for many kinds of harmful software, but the different types behave in distinct ways.

A worm is a program that spreads by itself across networks without needing to attach to another file, often by exploiting weaknesses in software. A Trojan, named after the wooden horse of legend, disguises itself as something useful or harmless to trick a user into running it, then carries out hidden harmful actions. Such programs may delete or corrupt data, steal passwords, or let an attacker control the machine remotely. Keeping software updated reduces the openings these threats use.

Antivirus software protects a computer by scanning files for known threats and watching for suspicious behaviour, then blocking, removing or isolating anything it identifies as harmful. Because new threats appear constantly, antivirus programs rely on regularly updated information to recognise them. A separate nuisance is the virus hoax, a false warning, often spread by email, that describes a non-existent threat and urges people to forward it. Recognising hoaxes avoids needless alarm and the spread of misinformation, while genuine protection comes from updated software and cautious habits.

Frequently asked questions

What is the difference between a virus and a worm?

A virus attaches to a file and spreads when that file is run, while a worm spreads by itself across networks without needing a host file.

What is a Trojan?

A Trojan is malware disguised as something useful or harmless to trick the user into running it, after which it performs hidden harmful actions.

What is a virus hoax?

It is a false warning about a non-existent threat, usually spread by email, that urges recipients to forward it, causing alarm but no real infection.