What is a computer virus? According to wikipedia.org; “A computer virus is a computer program that can replicate itself and spread from one computer to another”. Virus has become synonymous for all infections that your computer could become compromised with. The word virus has become a general term as well. The types of viruses are one thing while the variations on themes are vast.
Trojan Horse
Metaphorically a “Trojan Horse” has come to mean any trick or stratagem that causes a target to invite a foe into a securely protected bastion or space.
Detail from The Procession of the Trojan Horse in Troyby Domenico Tiepolo (1773), inspired by Virgil’s Aeneid
Wikipedia describes a Trojan virus as, “A Trojan horse, or Trojan, is software that is intended to perform, simultaneously, a desirable (expected) effect and a covert (unexpected) effect. Trojan horses can make copies of themselves, steal information, or harm the computer system. The term is derived from the Trojan Horse story in Greek mythology“.
Rootkit is explained as “A rootkit is a stealthy type of malicious software (malware) designed to hide the existence of certain processes or programs from normal methods of detection and enables continued privileged access to a computer. The term rootkit is a concatenation of “root” (the traditional name of the privileged account on Unix operating systems) and the word “kit” (which refers to the software components that implement the tool). The term “rootkit” has negative connotations through its association with malware“.
Malware or Rogue security software is in a league all of it’s own. This software is adept at encouraging the operator to click on a pop up screen. After clicking on the pop-up screen you get infected and the click triggers a scare tactic that directs its victims to pay for removal of the viruses that have just been installed on your computer. Oddly, if instead of clicking on the malware pop-up, the user shuts off their computer the potential malware infection is gone. Some of the more sophisticated malware programs will install themselves if all the operator dose is mouse over the malware pop-up.
The image below shows how sophisticated the virus writers have become. This is a current variation on the theme of malware at its worst. Look at the crest on the left upper corner. Although it is a good representation of the Microsoft crest it is not even close. With the blue background, crest, and general clean graphic look, it is easy to be tricked.
Above is one of Microsoft’s many logos currently in use. I believe that the only reason that the Black Hats don’t use a more accurate logo is copyright infringement. Microsoft could sue, and they would, if the bad guys used a perfect replica of any of Microsoft’s registered trade marks. Money would be on the line and blood would be in the streets. Maybe then the giants would really take steps to prevent unwanted intrusions? Or maybe I am still naive? The real question is why haven’t the major software companies already taken aggressive steps to prevent intrusion in the first place?
All of the most common and modern virus software out there today takes advantage of various virus software that has been written before in its principal character. Meaning that a virus creator can create a program that takes advantage of the characteristics of Trojans, Rootkits, Worms and other viruses when creating a malware program for example.
The most important thing to remember is DON’T CLICK BEFORE YOU THINK.
The second thing to remember is, if you have performed an action that you believe has compromised your computer, immediately perform a system restore and then run your anti-virus program.
Many times when I receive a computer in for repair the owner will state “this just happened yesterday”. When in fact it may have happened as long as three months before. It is likely that, that computer finally came to a point where it has become inoperable.