Viruses & Malware

With the birth of the Internet there are new ways to communicate, send data from one part of the world to another, explore places to shop, share your stories, and even play games.

But as with many good things, the Internet has its dark side. There are a plethora of cyber-risks that you face anytime that you go online, from malware to hackers to Denial of Service Attacks.


Malware is short for "malicious software." It is software designed to infiltrate or damage a computer, server, computer network, or personal device without the owner's informed consent. Users are warned only to open attachments they trust, and to be wary of items received from untrusted sources. Malware is commonly used by hackers to remotely access computers, exploit personal information and corrupt or destroy important data.

Types of Malware

  • Virus: A form of malware that relies on human interactions (such as downloading or opening files) to spread.
  • Trojan: A form of malware that masquerades as a legitimate application.
  • Worm: A form of malware that can self-replicate and distribute itself across multiple devices without human intervention.
  • Spyware: A form of malware that discreetly captures and transmits sensitive information from a device (like keystrokes or webcam photos).
  • Adware: A form of malware whose primary purpose is to serve obtrusive or unexpected ads on the compromised device.
  • Chargeware: A form of malware that charges the victim money without his/her knowledge or consent.
  • Ransomware: A form of malware that restricts access to a device unless the victim pays to have it unlocked.
  • Rootkit: A form of malware that enables unauthorized access to a device without being detected.

While many of these dangers can render a computer or the data on it useless, there are ways to mitigate the damage, and in many cases to stop the attack before it becomes a problem at all.


The term "spyware" refers to any computer technology that gathers and redistributes personal information about a person or organization without their knowledge or consent. Most commonly, it installs itself on a computer to secretly gather information about the user that is then sent to advertisers and other interested parties. Spyware can be installed on a computer any number of ways - as part of a new software application, a "drive-by" website, or even a computer virus.

Spyware often downloads with items identified as "free downloads" and does not notify the user of its existence or ask for permission to install the components. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements; theft of personal information (including financial information such as credit card numbers); monitoring of web-browsing activity for marketing purposes.

The malicious nature of spyware is somewhat subversive. Some will send advertisers a report on all the sites you visit, while others will send information about your computing or online purchasing habits. Spyware programs can collect various types of personal information, such as Internet surfing habit, sites that have been visited, but can also interfere with user control of the computer in other ways, such as installing additional software, redirecting web browser activity, accessing websites blindly that will cause more harmful viruses, and displaying pop-up advertisements.

Most spyware is installed without users' knowledge.

The most effective tool against spyware is common sense. For instance, you should read the End User License Agreement (EULA) attached to any software that you install. In the EULA, many programs indicate that they include spyware components.

There are programs on the Internet that claim to remove spyware infections, but in fact, contain spyware. The best defense against this type of program is due diligence. Do your homework, and fully research any program or application you may potentially install.

In the end, the best spyware-stopper is an informed computer user.


Adware is software that displays advertising banners on web browsers. Adware programs are typically installed as separate programs that are bundled with certain free software. Many users inadvertently agree to installing adware by accepting the End User License Agreement (EULA) on the free software. Adware are also often installed in tandem with spyware programs. Both programs feed off of each other' functionalities - spyware programs profile users' Internet behavior, while adware programs display targeted ads that correspond to the gathered user profile.


Like most anti-virus software, many anti-spyware/adware tools require a frequently-updated database of threats. As new spyware programs are released, anti-spyware developers discover and evaluate them, making "signatures" or "definitions" which allow the software to detect and remove the spyware.

Tips to Avoid Malware, Spyware and Adware

  • Use security software to provide spyware protection and proactively protect from other security risks
  • Configure your firewall to block unsolicited requests for outbound communication
  • Do not accept or open suspicious error dialogs from within the browser
  • Spyware may come as part of a "free deal" offer - do not accept free deals
  • Always read carefully the End User License Agreement (EULA) at install time and cancel if other "programs" are being installed as part of the desired program
  • Keep software and security patches up to date
  • Only open email attachments that come from a trusted source and that are expected
  • Have email attachments scanned by security software prior to opening
  • Delete all unwanted messages without opening
  • Do not click on web links sent by someone you do not know
  • Keep security patches up to date


A virus is a computer program that can attach itself to host files and replicate itself repeatedly, usually without user knowledge or permission. Viruses attach to files in such a way that when the infected file executes, the virus also executes. Other viruses can sit in a computer's memory and infect files as the computer opens, modifies, or creates new files.

A computer system infected with a virus can display various symptoms. Some viruses damage files and operating systems, but neither symptoms nor damage are definite indicators to the presence of a virus or essential virus components.

Virus Hoaxes

Virus hoaxes are either deliberate or unintentional email messages warning people about a phony virus or other malicious software program. They will sometimes instruct you to install a phony program to "remove the virus", which may contain malware that can damage your computer.

Virus Detection and Prevention Tips

Get protected. If you don't already have virus protection software on your personal computer or mobile devices, you should install the latest anti-virus software.

Scan your system regularly. If you're loading anti-virus software for the first time, it's a good idea to let it scan your entire system. Often, the anti-virus program can be set to scan each time the computer is rebooted or on a periodic schedule. Some will scan in the background ("real time") while you are connected to the Internet. Make it a regular habit to scan for viruses.

Don't open attachments. One of the best ways to prevent virus infections is not to open attachments, especially when dangerous viruses are being actively circulated. Another option is to scan attachments for viruses before opening them.

Update your anti-virus software. Once you have virus protection software installed, make sure it's up to date. Most anti-virus programs have a feature that will automatically link to the Internet and add new virus detection definitions whenever the software vendor discovers a new threat.

U.S. Computer Emergency Readiness Team has useful information on how anti-virus software programs work.

McAfee's Virus Detection and Prevention Tips