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Common computer infections

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Despite some advertising claims to the contrary, ALL computers (PCs, Macs, Linux based machines) are susceptible to viruses or other cyber-attacks.


Computer viruses are programs written to alter the way your computer operates without your permission or knowledge. Most viruses can replicate themselves and spread to other files or even other computers. Worms are programs that use computer networks to take advantage of security flaws and replicate themselves to other systems.


Spyware is a type of program that watches what you do on your computer and sends that information to a third party over the Internet. Some spyware tracks what websites you visit and sends the information to an advertiser. Others try to record what you type in an attempt to capture passwords or credit card numbers. Still others simply launch pop-up advertisements constantly.


A computer virus is a program that can copy itself and infect a computer without the permission or knowledge of the owner. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.


Malware, a portmanteau from the words malicious and software, is software designed to infiltrate or damage a computer system without the owner's informed consent. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.


Adware or advertising-supported software is any software package which automatically plays, displays, or downloads advertisements to a computer after the software is installed on it or while the application is being used. Some types of adware are also spyware and can be classified as privacy-invasive software.

Trojan Horse

A Trojan horse, or trojan for short, is a term used to describe malware that appears, to the user, to perform a desirable function but, in fact, facilitates unauthorized access to the user's computer system. The term comes from the Trojan Horse story in Greek mythology. Trojan horses are not self-replicating which distinguishes them from viruses and worms. Additionally, they require interaction with a hacker to fulfill their purpose. The hacker need not be the individual responsible for distributing the Trojan horse. It is possible for hackers to scan computers on a network using a port scanner in the hope of finding one with a Trojan horse installed.



Antivirus (or anti-virus) software is used to prevent, detect, and removemalware, including computer viruses, worms, and trojan horses. Such programs may also prevent and remove adware,spyware and other forms of malware.

Any computer and internet user, regardless of the reasons that they are online, need to have the latest antivirus software programs installed on their computer. Even though most of these programs come already installed with your computer and are free, antivirus software is absolutely essential. It also plays an important role in computer safety, as it can protect your vital documents and files from becoming damaged or lost forever.

At ITS we have a number of such antivirus software, and fixes available, that can help your computer get rid of these infections, like Avira, ComboFixMalwareBytes, etc.

Sources and Relevant Links

computer viruses
trojan horses