Computer Security and Virus Prevention

Computer VirusTips for computer security and to prevent viruses

You must run quality security software on your computers to protect your work and private data from viruses, spyware, and other security threats. When it comes to security, there is no substitute for quality. See below our recommended quality solutions. If any of the following is difficult for you, get an IT Expert to do it for you.

Consider doing the following or so  your work/data is not compromised (think of it as locking your front door):
  • Install reputable anti virus software - Be sure to regularly update your 'virus definitions' e.g. once per week )
  • Install a firewall and malware applications:  Firewalls will help monitor incoming and outgoing network traffic. Malware programs will help detect and remove unwanted spyware/malware. Many anti-virus packages include both a firewall and anti-malware.  If not, consider purchasing a product from a reputable source.  Each component provides an additional layer of security.
  • BEWARE OF ATTACHMENTS - Do not open email attachments you are not expecting. Viruses come with some very nasty messages to trick you into opening the attachment e.g. "Your email account has been cancelled, see attachment for details". Even worse, the virus looks like it comes from an email address you recognize e.g. from [email protected] (where 'your domain' is the domain name that you use). Virus attachments can have the following 'file extension': .exe, .pif. If you receive a .zip attachment and open it - make sure it doesn't contain a file with one of those

    extensions. Do not open attachments you haven't requested, even if they appear to be from people you know.

Why do I receive, notices that emails from me could not be delivered - when I didn't send the email? How did someone else send an email that looked like it was from me? Why do such emails seem to be from someone who is not in my organization?

This is usually caused by a virus on someone else's computer sending the emails, but making it look like the emails are from you, or to put it another way: A virus that spoofs the 'from address'. The important (and annoying) thing to note is that the virus is probably not on your computer, it is on someone else's. So even if you have quality anti-virus software that keeps your computer clean, there is someone else out there who's computer is infected and sending these emails out.

How viruses spoof the from-address in emails?

  1. You have effective anti-virus software, so your computer is clean,
  2. You send an email to Fred,
  3. Now your email address is in Freds address book in his email software,
  4. Fred does not have effective anti-virus software, and his computer has a virus,
  5. The virus on Freds computer scans his address book for all of the email addresses on it,
  6. The virus sends email to every address on Freds address book,
  7. The virus emails do not say they are from Fred!, The virus pics another address from Fred's address book and puts it in the 'From field' in the outgoing email. The virus may combine the name from one address and the domain from another, creating a 'from address' that does not exist.
  8. These emails are received by other computers, which detect the virus (because they have good anti virus software) and reject the email,
  9. When the receiving computer rejects the virused email it sends an 'Undeliverable' to the sender e.g. something like 'Subject: /Delivery Notification: Delivery has failed'.
  10. But! the 'Undeliverable' note goes to the spoofed from address (not to Fred) e.g. the 'Undeliverable' note could be sent to you.
  11. Often there is no trace of Freds real address in the virus email or the 'Undeliverable' note, so you can not tell who's infected computer is sending these emails.


  1. What is malware? 
    Malware – formed from the words malicious and software – is a general term used by computer professionals to refer to many different kinds of computer software designed to infiltrate or damage a computer system without the owner’s knowledge or consent. Malware includes computer viruses, worms, trojan horses, spyware and many other malicious and unwanted software types. 

  2. How can a malware infection occur?
    Malware can infect a user’s computer through many paths, including pop-up messages that ask users to download things, links in web pages or e-mails, infected websites and many other methods that can sometimes even be invisible to the user. Malware is often used in conjunction with phishing scams.

  3. What are the consequences of malware?
    At a minimum, malware is a nuisance, sometimes displaying unwanted advertising or using a user’s computer to send spam. At its worst, malware has the potential to steal personal and financial information ranging from browsing habits to e-mail address lists to online banking passwords and even identity theft.

  4. How can you protect yourself against malware?
    While there is no single fool-proof method, users should keep their anti-virus software up to date and running and keep their operating systems and applications updated with the latest patches from the manufacturers.

    Other common suggestions include exercising extreme caution with e-mail links and attachments and using firewalls to protect information on personal computers. Also look for login windows or messages that appear strange or different, which could be signs that your computer has been affected with malware.

  5. What should I do if I'm affected by malware?
    Remember to always remain vigilant to the risks of malware, phishing and other suspicious activities by taking steps to minimize risk.
  • Make sure your PC is updated and secure
  • Be very skeptical of random pop-up windows, error messages and attachments
  • Remove spam from your life
  • Think twice before installing any new software