Malware is malicious code intended to damage the system on which it is downloaded. Malware comes in various types. The best known are the following:
Troy Horse
This is malicious code, usually exchanged via email, that appears to be a useful program but has a hidden agenda. An example is the Zlob Trojan, 2005/06. This would copy itself, create changes to directories, etc. The Waterfalls screen saver Trojan claims to be a screen saver, but downloads viruses and scripts while running. To prevent this attack, allow the file to be scanned before running it, as malicious scripts will be recognized.
Virus
A virus is malicious code that replicates to other programs and users via email and various other routes. Then it causes problems for any user or program it is associated with. FACTS. Spaceflash is a known virus from 2006. This virus was on MySpace “about me” pages and targeted anyone accessing an already infected “about me” page. The virus would then delete the new user’s page and replace it with html code. A common way to receive a virus, which replicates itself through the computer’s memory, is by opening an email attachment. Good common sense and a virus scanning package are the best ways to detect viruses.
logic bomb
This is a malicious code that is hidden and goes to work when a preset determination is met. A disgruntled employee ran a logic bomb to manipulate stock prices. This seems to be a popular reason to use a logic bomb. The answer may be to treat your employees well, while keeping an eye out for disgruntled employees. In 2006, a USB administrator PaineWebber was jailed for planting a logic bomb that would delete files on a given day. The manager bought shares and predicted what would happen to the company (because of his bombing).
worm
A worm is a program that makes its way through the system without the user doing anything. The Morris worm shut down the Internet for days. The Morris worm gained unauthorized access to computers. It caused a buffer overflow so people couldn’t access their Internet in 1988. The types of worms are now similar to email viruses and common sense should be used when opening files.
applet
An Applet is a program that can be useful but can cause problems for other programs on the system. An example of applet malware is receiving an automatic applet download when visiting a website. JavaScript is activated and can execute malicious scripts. There is a Java security model that requires Java to run in a restricted environment to control malicious content.
Most antivirus programs have removals for certain malware. One can go to some antivirus sites to scan their system and download a removal tool to remove the malware from the system.