Security threats and countermeasures

In this section, we are going to take a look at various security threats and how to implement countermeasures.

Viruses

A virus is a malicious piece of code that is designed to cause harm to a system, such as a computer. Viruses are not executed on their own usually but require the action of a person; this action can be done by simply clicking or running a virus-infected file, which will trigger the malicious code execution.

A notable type of virus is known as the worm. A worm is a self-replicating virus that can propagate throughout a network without any assistance from humans.

Imagine creating a program that can self-replicate without user interaction and overwhelm system resources so much that a worm-infected system becomes almost, if not completely, unusable. Once a worm virus has been created and its self-replicating process is triggered, disinfecting a network is quite difficult.

To prevent malware infections from viruses and worms, it is recommended...