Reference number: CH001045

How does a computer get infected with a virus or spyware?

Question:

Answer:

There are literally dozens of different ways a computer can become infected with spyware, viruses, and other malware. Below is a list of the most common ways a computer can contract these infections listed in the order we believe are most commonly done.

Tip: All people who use the computer should be aware of how to properly use the computer and protect it from malicious software.

Accepting without reading

By far one of the most common ways a computer becomes infected is the user simply accepts what he or she sees on the screen without reading the prompt and/or understand what it's asking.

Some common examples:

While browsing the Internet, an Internet advertisement or window appears that says your computer is infected and/or that a unique plug-in is required. Without fully understanding what it is you're getting, you accept the prompt.
When installing or updating a program, you're prompted (often checkboxes already checked) if it's ok to install additional programs that you may not want or are designed to monitor your usage of the program.

Opening e-mail attachments

Another very common way people become infected with viruses and other spyware is by opening e-mail attachments, even when from a co-worker, friend, or family member. E-mail addresses can be easily faked and even when not faked your acquaintance may unsuspectingly be forwarding you an infected file.

When receiving an e-mail with an attachment, if the e-mail was not expected or from someone you don't know simply delete it. If the e-mail is from someone you know, be cautious when opening the attachment.

Not running the latest updates

Many of the updates, especially those associated with Microsoft Windows and other operating systems and programs, are security updates. Running a program or operating system that is not up-to-date with the latest updates can be a big security risk and can be a way your computer becomes infected.

Microsoft Windows users can find information about how to update Windows on document CH000545.

In addition to running operating system updates, the plugins associated with your browser can often contain security vulnerabilities. Make sure you have the latest versions of plugins. Click here to view installed plugins and their versions.

Pirating software, music and/or movies

If you or someone on your computer is participating in underground places on the Internet where you're downloading copyrighted music, movies, software, etc. for free, often many of the files can contain viruses, spyware and/or malicious software.

No anti-virus spyware scanner

If you're running a computer with Microsoft Windows it's highly recommended you have some form of anti-virus and spyware protection on that computer to help clean it from any infections currently on the computer and to help prevent any future infections.

A listing of anti-virus scanners including free programs can be found on document CH000514.
Spyware protection programs can be found on document CH00578.

Downloading infected software

Finally, downloading any other software from the Internet can also contain viruses and other malware. When downloading any type of software (programs, utilities, games, updates, demos, etc.), make sure you're downloading the software from a reliable source and while installing it you're reading all prompts about what the program is putting on your computer.