Viruses and Malware
The term "computer virus" is commonly used to refer to any piece of malicious software, or "malware" that can destroy computer-based information, shut down networks by creating enormous amounts of network traffic, and cost organizations potentially millions of dollars in clean-up costs.
Computer viruses are not the only type of malware. Malware also includes worms, spyware and adware. This section describes the major types of malware and how to prevent becoming a victim.
Viruses
The constant redistribution of viruses, augmented by new viruses created every day, place every computer that does not have anti-virus software installed at significant risk. Hundreds of thousands of viruses have been created by executing an infected program on a computer. The infected code searches through the computer and could then potentially execute destructive commands, such as those to erase the contents of the hard drive.
How your computer can become infected
Viruses can be embedded in Word and PDF documents, spreadsheets, HTML pages, that can be set to run when the document is opened. As a result, viruses can be spread through email, files on USB drives, CDs, and DVDs. Email viruses are the most popular method of choice because they are easy to develop. Email viruses usually replicate when an infected program or document is opened, the program or document executes to open the email directory and to send a copy of itself as an email attachment to a predetermined number of email addresses, and as the recipients open the attachment in the infected email, the process repeats itself.
Worms
Worms spread by exploiting system vulnerabilities in computers that share a network with the infected device. These vulnerabilities can be found in operating systems, network software, web server software, database software, and applications. Worms replicate when an infected program or document is opened. When the worm detects a vulnerability on the computer, it infects the service on the device.
Spyware & Adware
Spyware and adware are programs that can be secretly installed on your computer when you access the websites on the Internet that distribute them. These programs were created to determine your interests so that Internet sites can tailor their advertising to those interests by storing the websites you visit in small files on your computer known as "cookies". In addition to invading your privacy, these programs can install software that degrades the performance of your system, uncovers confidential data on your system, captures passwords, and destroys data. Typically, these programs are installed through your browser when you visit questionable websites, i.e., websites of unknown individuals or little known organizational entities. As soon as you open a web page that hosts spyware/adware, the site will download the program and install it on your system - assuming that the security level of your web browser software is not restrictive.
How to protect yourself against malware
- Be skeptical of random pop-up windows and email attachments.
- Be cautious when installing new software.
- Do not use the admin account on your computer unless you are installing new software or adding a new account. That way you will not have privileges to unintentionally install malware on your computer, but will instead receive an alert message that installing software requires administrator privileges.