1.Types Of Virus
a.Salami Attack
b.Worm
c.Trojan Horse

What is Worm?
•Computer Worms are viruses that reside in the active memory of a computer and duplicate themselves. They may send copies of themselves to other computers, such as through email or Internet Relay Chat (IRC).

What is Salami Attack?

•A salami attack is a series of minor data-security attacks that together results in a larger attack. For example, a fraud activity in a bank where an employee steals a small amount of funds from several accounts, can be considered a salami attack.
•Crimes involving salami attacks typically are difficult to detect and trace.

What is Trojan Horse?

•A Trojan horse program is a malicious program that pretends to be a begin application; a Trojan horse program purposefully does something the user does not expect. Trojans are not viruses since they do not replicate, but Trojan horse programs can be just as destructive.
•Many people use the term to refer only to non-replicating malicious programs, thus making a distinction between Trojans and viruses.