UNDERSTANDING MALWARE

The term Malware is actually kind of a play on words - "MAL" is bad and "WARE" like softWARE or hardWARE.

So just what does a virus, worm and Trojan do?

Virus
Probably the best known type of Malware
They can replicate themselves
They attach to a host file (usually an executable file whose name ends in EXE)
They are activated by a human being (or, I suppose, a very bright monkey with a valid password....) interacting with the host file (like by opening it)
Thousands of new viruses are written every month
Can damage your computer data, steal your sensitive information and even allow someone to control your computer!

Worm
Type of virus
Does not require human intervention to activate nor a file to be a host
Can spread itself by looking through all of your email contacts and sending itself to them
Can damage your computer data, steal your sensitive information and even allow someone to control your computer

Trojan Horse
Used to conquer an ancient city; soldiers hid in it in order to infiltrate....oops, ah, sorry, wrong blog! ;-)
Masquerades as a legitimate program; you think you're downloading/installing something good
Do not replicate themselves nor infect other files
A common symptom is many pop-up windows appearing when you are on the Internet (often with Internet Explorer browser)

Phishing
Attempt to steal your password by impersonating a helpdesk or other authorized network administrator, usually with an email
The user is fooled into responding to the email with login credentials
HELP DESK PEOPLE WILL NEVER ASK YOU FOR LOGIN CREDENTIALS/PASSWORDS IN AN EMAIL!

Terminator
Hostile robot that can look like a human being
Sent back from the future
Will attempt to steal your password if your name is Sarah Conner

In a subsequent post we'll talk about protecting yourself against these and other threats