Protecting Your Computer

First The Bad News

There are many threats to your PC. They include malicious software such as computer viruses, worms, Trojans, spyware and Botnets.

Some Websites Can be Bad

Some websites can contain malicious software that can infect your machine. The infections can be used to steal information from your computer or use your computer to attack others and take the form of worms, Trojan horses, spyware, botnets etc. But how can a website exist with malicious software and why do people visit those sites and then get infected? The answer is the deviousness of the perpetrators.

Genuine websites can be hacked into. Having gained access the hacker can install the malicious software into the site (unknown to the site owner). The site is then able to pass the malicious software to other user's computers that visit that site.

Dedicated websites can also be specifically created to hold malicious software. When a user visits the site the computer will get infected. Three ways in which a user may be attracted to the website:

  • When a user attempts to access a genuine website, the attempt is redirected to the "fake" site.
  • By taking a link to the site from an email, the email basically being of the SPAM variety.
  • The "fake" site has some content of current interest that would be found in web searches. Recent examples include a site claiming information about swine flu and another with information about the actor Patrick Swayze.

The lesson from this is to be careful about websites you visit and, of course, have your antivirus etc software up to date.


Computer viruses are software programs that are designed by attackers to invade your computer, to interfere with its operation, and to copy, corrupt or delete your data. These malicious software programs are called viruses because they are designed not only to infect and damage one computer, but to spread to other computers.

Viruses are often hidden in programs or e-mail attachments, this may include computer games, video clips or photos. Many such viruses are spread inadvertently by computer users, who unwittingly pass them along by e-mail to friends and colleagues.


Worms are sophisticated viruses that can replicate automatically and send themselves to other computers by taking control of certain software programs on your PC.

Trojan Horses

Other viruses, called Trojans in honor of the Trojan horse, actually masquerade as beneficial programs while quietly destroying your data and damaging your system.


As the name implies, spyware is software that is designed to secretly monitor the things you do on your computer, and to either report your behavior to the person who designed the program or to take some action based on that information.

Spyware may bombard you with pop-up advertising related to the types of Web sites you visit regularly, collect personal information about you, or change the settings on your computer without your knowledge or consent. Spyware can also make it possible for criminals to steal your identity.


A Botnet is a collection of computers running a common application and which can work autonomously and automatically. The name comes from the idea of a network of robots. Botnets are typically coordinated in a command and control structure where a central server distributes updates and commands to each member. In this context the implication is that the software is used for coordinated malicious purposes such as launching denial of service attacks to overload systems, large scale spam email shots and spying to log user details such as credit card details. The software gets into the computers by exploiting vulnerabilities such as a web browser vulnerably, worm, Trojan horse etc. Botnets like working in organisations such as Universities due to their high speed connection to the internet. It is possible for non-technical people to buy access to already deployed Botnets to do their bidding. Recent Botnets include ‘conficker’ and ‘storm’.

Now The Good News

The good news about viruses, worms, spyware and other malicious software is that with a little knowledge, you can reduce your risk of falling victim to them and diminish their potential impact.

Four Simple Steps to Protect Your PC

By taking four basic steps, you can help secure your PC from many malicious software attacks 

These four simple steps are: 

  1. Use a firewall
  2. Keep your operating system up to date, by turning on automatic update features in Windows
  3. Install and maintain Antivirus software
  4. Install and maintain Anti Spyware software

Even Better News - Free Anti-Virus Software

Aston University currently uses Microsoft Forefront Endpoint Protection as its chosen anti-virus software and holds a site-licence for this.  The software is installed on all student lab computers and staff desktop computers on campus. 

A free version of this is available for personal use called Microsoft Security Essentials. See software use at home for further details.

Picture of a virus