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Posted on Oct 30, 2017 in Tackling Malware | 0 comments

Understanding computer viruses

Worried about computer viruses on your Windows machine? Unsure of which antivirus to choose? Read this guide to find out what viruses are and how to deal with them.

Quick links for dealing with viruses:-
What are viruses?
Don’t let computer viruses ruin your day
Which antivirus software is the best?
Comment on this article

Computer viruses are big news in the world of computer security and in the world of Windows operating systems. Now that most of us use always-connected broadband internet, it has become increasingly easy for viruses to spread between machines. What are viruses and what should you do to avoid them?

What are viruses?

Sci-fi virus

Boo! Popular media and science fiction has portrayed the computer virus as something mystical and magical. In reality, it is no more than a malicious computer program.

Despite what you may have heard, computer viruses are not magical. They cannot be transmitted through the air and while some of them are able to erase information from your computer, they cannot erase backup DVDs you have made and they cannot cause your computer to explode! Computer viruses are computer programs, just like every other bit of software that runs on your PC. What makes computer viruses different however is the fact that they are designed to copy themselves, throughout your computer’s memory or hard drive, or even across the internet. Many computer viruses have malicious components too, and may try to cause all sorts of mischief from slowing down your computer to allowing hackers to gain entry. Click here to see what Microsoft have to say about computer viruses.

What is the Difference Between Computer Viruses and Spyware?

Spyware is software specifically designed to watch things you do on your PC, perhaps to gather data on the websites you visit, or music you listen to. Plain spyware does not copy itself or exhibit other malicious behaviour, although many computer viruses are also spyware or contain spyware components. Not all spyware is necessarily bad. The popular music utility LastFM for example, is considered by some to be spyware, as it tracks what music you listen to. However, it uses that data to recommend bands and music to you that you might like, which makes it great fun to use and highly recommended!

What about “Trojans” ?

Trojan horse

Beware of Greeks bearing gifts. Actually, beware of any shady website offering freebies on the net.

You remember the story of the Trojan horse, right? The Greeks manage to convince the Trojans that a giant wooden horse, containing lots of their warriors, was actually a gift from the Gods. The Trojans, thinking the Gods had smiled on them, took the horse inside their giant walled city, and then the Greeks burst out surprising them and overthrowing the city. Trojans that you get on your computer don’t look like horses, but they may look like games, or pictures, or other files which may seem to be fun to play with. In actual fact when you click the file you will get a nasty surprise as a computer virus or malicious program lurks inside. Trojans can be computer viruses or spyware and are generally to be avoided.

What about “Ransomware” ?

Ransomware is a specific new threat that has become more prevalent in the last few years due to the spread of broadband connections. The increasing speed of computers and a general lack of security measures in many big companies and government owned facilities such as hospitals and schools has made Ransomware increasingly profitable. Ransomware may be delivered by a computer virus or a trojan, often an attachment to an e-mail such as an invoice or picture file. Once the ransomware program is on your PC, it sets about encrypting any data it can find on any attached hard drives. Once your data is encrypted, the criminals behind the software contact you and demand a ransom be paid in exchange for decrypting your data.

What about “Scumware”, “Parasites”, “Malware” etc

Ok so there are many buzzwords going around but they all boil down to one thing, computer programs that are bad news for you, the owner and user of your computer. So, we know that this bad software is out there, what can we do to avoid it?

Don’t let computer viruses ruin your day

Although there are a lot of viruses on the internet, it is important not to get carried away. With a few simple precautions it is easy to stay safe from this kind of threat online. Choosing good Antivirus software is only part of the solution, here are a few common-sense tips that every Windows user should follow:

Make Sure Your Operating System is Up To Date! If you don’t have automatic updates enabled (we recommend you do) be sure to check for Windows updates frequently. Virus writers exploit mistakes or bugs in the operating system in order to install viruses or help them spread. Once these problems are known, Microsoft issues fixes to prevent this, so always make sure your operating system is up to date. For more information on updating your Windows machine, visit our comprehensive updating Windows pages.

Make Sure Your Web Browser is Up To Date! Whether you use Firefox, Chrome, Microsoft Edge or Internet Explorer, making sure that you are using the latest version will help keep you secure. Most web browsers update themselves automatically, but you can always check by going to the menus and choosing “Help” and then “About”. Microsoft web browsers should update themselves automatically with Windows update. If you’re still using Windows 7, be sure to run at least Internet Explorer 11 and consider switching to Google Chrome or Mozilla Firefox.

Virus writers love bugs (mistakes in the software) in your web browser, they can use them to smuggle viruses aboard your PC. Once Microsoft, Google or Mozilla find out about these mistakes, they issue software updates to correct them.

Be Careful What Attachments You Open! Just because an attachment came from somebody you know, doesn’t mean it is safe. Before opening an attachment, at least read the rest of the e-mail. It is usually easy to tell if an e-mail has been written by a virus rather than a human. Antivirus software can help you here by automatically detecting if an attachment is safe, but no antivirus is completely fool proof.

Consider using “Limited” accounts wherever possible

Macintosh/OSX and Linux platforms are less often affected by computer viruses and other types of malicious software. While some people believe this is because virus writers simply ignore these platforms, it is likely that it is also due in part to the way in which these operating systems approach user account settings. On the Mac and on Linux, users have a limited account by default. Limited accounts can access most programs and files on the computer, but they cannot make changes to the system settings, such as the registry. Because of this, it is much harder for a virus to infect the system. Administrator accounts are only used on Linux and MacOS when changes need to be done to the system.

Windows has had limited accounts for some time now, however thanks to certain older (designed for Windows 98/ME) or poorly designed software packages that are not compatible with limited accounts, most users always run as an administrator, giving viruses and spyware a free run of the system (especially on Windows XP). If all your applications are compatible, then you should run limited user accounts whenever possible. With Windows Vista, Microsoft introduced User Account Controls (UAC). While the frequent prompts that UAC generated were a shock to some users, UAC is great for security because it makes it possible to run a standard user account for day-to-day computing activities, providing another layer of security. We recommend all Windows users run standard or limited user accounts.

Limited user accounts can be set up in the control panel, we show you exactly how to configure limited accounts in our online safety tutorials section.

Which antivirus software is the best?

Unfortunately there is no one correct answer to that question. However, out of the dozens and dozens of computer antivirus packages on the market, we have listed below some of the best for you to consider and we will be adding more recommendations soon. We believe that one and only one, (don’t ever be tempted to install more than one Antivirus package at once, they will just interfere with each other) of the packages below will be the right choice for almost everyone.


Bitdefender’s range of Antivirus and Firewall products have been winning awards across the internet for their excellent malware detection and prevention capabilities. Bitdefender gets our vote as the best premium antivirus solution on the market today.

Tutorials for Bitdefender are now available in our Antivirus Tutorials section.

Malwarebytes Anti-Malware

Malwarebytes range of antivirus and anti-malware software provides traditional, signature based virus detection along with heuristic type software. Heuristics can spot the behaviour of ransomware and browser exploits and stop them dead in their tracks, in many cases even when the malware in question is newly released and not yet widely detected by antivirus software.

Microsoft Security Essentials (for Windows 7)

Microsoft Security Essentials is undoubtedly one of the best value for money Antivirus packages on the market. Why? Because it is available for free! That is right, totally free. At that price, even the tightest budgets can afford antivirus protection. The product has a clean, uncluttered interface and good scanning speeds. Security Essentials is also free of advertising and unnecessary features such as registry cleaners or so-called system optimisers or heath checkers.

Tutorials for Microsoft Security Essentials are now available in our Antivirus Tutorials section.

Windows Defender (for Windows 8 and 10)

Windows Defender is the free antivirus software now bundled with Windows 10. Originally derided by some in the IT security sector, the software has been improving leaps and bounds and now offers a good line of defence against most threats.

The changing face of malware attacks

Malware is big business in the modern era. Highly organised gangs of cyber criminals, rogue businesses and even governments are developing increasingly sophisticated threats. In order to protect against these threats, antivirus software needs to run at a high privilege level on your PC. By that, we mean it needs to run with access to all parts of your operating system, even those normally secured away from software for security reasons. In our February 2016 TWT Newsletter we reported how security researches had shown that bugs in antivirus software made systems more vulnerable to certain, targetted attacks.

By installing any software on your computer, you increase the “attack surface”, that is, the number of places there could potentially be a bug (a software programming mistake) that can be exploited by malicious users or software. If you install software that runs at the highest privilege level, then that “attack surface” covers the most vital parts of your Windows operating system. Almost all antivirus runs with the highest level of administrator privilege (even if you only run your Windows account as a standard user). When you install an antivirus suite, you’re trusting that the vendor hasn’t made any serious programming mistakes that actually make your PC less secure. Given how complex and monolithic antivirus packages have become, that’s quite a leap of faith.

So are we damned if we do and damned if we don’t install antivirus software? Well, hopefully not. An attack on a specific antivirus program would have to be deliberately crafted to target that specific antivirus suite. Realistically, you would probably be more likely to encounter malware that had been designed to target some specific Windows components or perhaps your web browser (be that Internet Explorer, Microsoft Edge, Google Chrome or Mozilla Firefox). After all, not everyone uses the same antivirus software, but the vast majority of people using desktop or laptop computers still run Windows and use those Windows computers to surf the web.

Even so, this highlights the importance of choosing an antivirus suite engineered by a company with an excellent reputation. We like to support companies that offer “bug bounties” to researchers who can find mistakes in their software. This way, there’s financial incentive for the good guys to find and report these problems before the bad guys can exploit them for their own nefarious ends. Microsoft, Malwarebytes and Bitdefender all operate these programs.

The fight against malware will continue for decades to come, while it might seem like the bad guys are always winning, in actual fact, the number of incidents of malware infection amongst Windows users is dramatically down since the Windows XP era. Modern versions of Windows are much better protected than in the past and more modern web browsers include more advanced software techniques to protect their users.


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