What type of virus is this? You check your client’s “Sent Emails” folder and notice your client recently sent the same email to everyone on their contacts list. The emails have the same subject line as the malicious email they received. It almost seems like the email replicated itself…
Aha! Rather than a virus, which needs to be attached to a file or application to spread, you may have found a worm.
A worm is self-replicating code that copies itself from computer to computer without user intervention. This worm could be just as dangerous as a virus.
The worm could also replicate so much that it overloads your client’s system. By doing this, the worm could bring down the system and violate availability.