Viruses & Spyware

A virus is a file written with the sole intention of doing harm, or for criminal activity. There are many types of virus. Viruses and spyware are also known as ‘malware’

A worm, for example, can exploit security vulnerabilities to spread itself automatically to other computers through networks. A Trojan horse (or simply ‘Trojan’) is a program that appears harmless but hides malicious functions. Zeus (and its derivatives such as Gameover Zeus) is an example of a Trojan, capable of being used to carrry out many malicious and criminal tasks. Viruses may harm a computer system’s performance or data. Some are noticeable to the computer user, but many run in the background, unnoticed by the user. A virus may be designed to replicate itself.

Spyware is a type of virus that is specifically designed to steal information about your activity on your computer. Spyware writers have a number of different objectives, mainly fraudulent financial gain. Spyware can perform a number of illicit functions, from creating pop up advertisements to stealing your bank login details by taking screen shots of the sites you visit and even logging the keys you type. Spyware may also be self-replicating.

Potentially, a virus could arrive on your computer in the form of a Trojan, it could replicate itself before moving on to another computer (a worm) and also be designed as a piece of spyware.  Viruses and spyware are types of malware, which also includes rootkits, dishonest adware and scareware.

The risks

Viruses and spyware can attack your computer via the following means:

  •  Opening infected email attachments such as .exe files.
  •  Opening infected files from web-based digital file delivery companies (for example Hightail – formerly called YouSendIt, and Dropbox).
  •  Visiting corrupt websites.
  •  Via the internet, undetected by the user (worms are an example of this).
  •  Macros in application documents (word processing, spreadsheets etc).
  •  USB connected devices (eg memory sticks, external hard drives, MP3 players).
  •  CDs/DVDs.

Viruses and spyware can cause very serious consequences including:

  • Identity theft.
  • Fraud.
  • Deletion, theft and corruption of data.
  • A slow or unusable computer.

Internet security (antivirus/antispyware) software

It is vital to keep your internet security software up to date in order to provide the most complete protection. Thousands of new viruses are detected every day, to say nothing of the variants of new and existing ones. Each has a set of characteristics or ‘signatures’ that enable internet security software manufacturers to detect them and produce suitable updates.

Most internet security software automatically downloads these updates (sometimes referred to as ‘definitions’) on a regular basis, as long as you are online and have paid your annual subscription (for a paid-for product). This should ensure protection against even the latest virus threats.

Internet security software scans for viruses in a number of different ways:

  • It scans incoming emails for attached viruses.
  • It monitors files as they are opened or created to make sure they are not infected.
  • It performs periodic scans of the files on your computer.

Some internet security software also scans USB connected devices (eg memory sticks, external hard drives, MP3 players), as they are connecting. Some also highlights suspect websites.

Internet security software will not protect you against:

  • Spam.
  • Any kind of fraud or criminal activity online not initiated by a virus.
  • A hacker trying to break into your computer over the internet.

It is not effective if it is switched off or not updated with the latest virus signatures, and do bear in mind that no internet security software is infallible, so a new strain of  malware from a fraudulent attachment or bogus website may still evade your software.

Choosing  internet security software

For personal and home office use there are a number of choices that you can take to decide which internet security software to buy. Whichever you choose, make sure it is a repuable brand from a mainstream supplier, and get the best you can afford.

There are a number of internet security software independent reviews available on the internet, including this one from Tech Advisor:

  • Package or standalone internet security software. Most suppliers offer a program that only scans for viruses, as well as selling full security packages that provide other protection including firewall, spam filtering, antispyware and parental controls. Prices vary according to features included. A package should include everything you need to protect your PC against online threats, is easy to use as everything is controlled from one screen, and is cheaper than buying each component separately. An increasing number of packages cover not only your computer, but up to a certain number of your mobile devices as well.
  • Free internet security software.There are a number of products that are free for personal or non-commercial use. In most cases, these ‘free’ products are no-frills versions of purchasable products which the manufacturer hopes you will upgrade to in the future. The protection factor is likely to be equivalent to the paid-for version, but there may be limited or no technical support and some reduced functionality, for example in scheduling full scans, leaving your device vulnerable to the latest threats.
  • Internet security software for businesses. Typically, antivirus/antispyware software and internet security packages cover up to three computers. Businesses should consider business versions designed to make installation, updating and management easier on multiple computers.
  • Windows Defender software is included – and enabled by default – in Windows Vista, Windows 7, Windows 8 and Windows 10  The Microsoft product is designed to prevent, remove, and quarantine spyware in Microsoft Windows.

Some manufacturers and retailers provide various security software bundled with the computer. You do not have to use the security software supplied, but if you decide to keep it, do not forget to subscribe once the free trial period is over so that it stays up to date.

Where to get internet security software

Antivirus/antispyware software and internet security packages are available to purchase from a variety of high street and online retailers as well as from the software manufacturers’ own websites. When purchasing in store, it is normal to load a disk and then download updates over the internet when prompted. When purchasing online, you will automatically download the latest version incorporating all updates.

Free antivirus/antispyware software and internet security packages as described above, may be available from some internet service providers (ISPs) and banks as part of your account.

Virus & spyware protection

Apart from installing internet security software and keeping it updated, we recommend a number of other ways in which to keep your computer protected against viruses and spyware. After all, prevention is better than cure.

  • Do not open any files attached to an email from an unknown, suspicious or untrustworthy source.
  • Uninstall one antivirus program before you install another.
  • Be careful with USB connected devices (eg memory sticks, external hard drives, MP3 players) as they are very common carriers of viruses.
  • Be careful with CDs/DVDs as they can also contain viruses.
  • Do not open any files from web-based digital file delivery companies (eg Hightail, Dropbox) that have been uploaded from an unknown, suspicious or untrustworthy source.
  • Switch on macro protection in Microsoft Office applications like Word and Excel.
  • Buy only reputable software from reputable companies.
  • When downloading free software, do so with extreme caution.

Jargon Buster

A Glossary of terms used in this article:


A file written with the sole intention of doing harm, or for criminal activity.


Universal Serial Bus: a means of physically connecting computers and peripherals such as external storage, keyboards and MP3 players.


Software posing as an authentic application, which actually conceals an item of malware. Term comes from Trojan Horse in Greek mythology.


Malware that secretly monitors a user's activity or scans for private information.


Unsolicited commercial e-mail. Also known as junk e-mail.


The technology used to store sound files, typically for music or podcasts.

.exe file

Executable file: used by programs to install and run on computers.