Computer Viruses

What is a Computer Virus?
A computer virus is a computer program that can spread across computers and networks by making copies of itself. Viruses can have very harmful side effects such as display irritating messages, corrupt documents, and even delete all the files on your computer.

How Viruses Infect Your Computer
A virus program has to be run before it can infect your computer. A bad file on a disk, an e-mail attachment, or in a download from the Internet can all infect your computer. As soon as the file is launched, the virus begins to run.

E-mail Viruses
Many people seem to think that they cannot get a virus just by opening an e-mail, but that is not true. Some of today’s e-mail viruses actually begin to run as soon as you open the e-mail. E-mail attachments are still the greater security risk. Any type of attachment may carry a virus and infect your computer.

Tips to Stop E-mail Viruses

E-mail Virus Alert - MyDoom Virus
The latest MyDoom e-mail virus is spreading around the world. The virus is a mass-mailing worm that sends e-mails with messages that look like mail system errors and other warning messages.

What Does the MyDoom Virus Do?
The MyDoom virus spreads via e-mail through SMTP (Simple Mail Transfer Protocol). It gathers target recipients from the Windows Address Book, the Temporary Internet Files folder, and by scanning the hard drive.

When it finds an e-mail address, it gets the domain name of that e-mail address and queries Google, Yahoo, Lycos and AltaVista search engines to find e-mail addresses in the same domain. It does this to gather more addresses to send spam. Besides sending spam, the virus also carries backdoor functionalities that leave the infected machine vulnerable to remote access.

MyDoom uses the following text strings as subjects for infected e-mails that it sends:

Returned mail: Data format error
Returned mail: see transcript for details
Delivery reports about your e-mail
Mail System Error - Returned Mail
Message could not be delivered
delivery failed
report
test
status
error
hi
hello

If Your Computer Has Been Infected
This is a free cleaner tool for the MyDoom virus and many other major viruses. You may also use this tool if you are not sure if your computer has been infected.

McAfee AVERT Stinger

How to Prevent Viruses
Anti-virus software is an important part of preventing viruses. The software can detect viruses, prevent access to infected files and often eliminate the infection. There are many types of anti-virus software programs on the market, but purchasing the software is just the first step. It is very important that you update your software on a regular basis.