• Malware is a word used in place of the longer phrase malicious software.
• Computer pathogens are any sorts of software that are intended to do harm to computing systems

I intend on using the word pathogen to describe a huge variety of ways to use software to attack including viruses, spyware and so on. 

There are quite a variety of ways that pathogens and/or malicious software can be be used to attack other systems.  Several of the attacks we have described so far rely on some sort of software to implement them.  The list below gives some general categories of the different types of pathogenic code/programs that can be used.  This list is definitely not complete, nor does every piece of malware fit neatly into exactly one of these categories.  But developing these categories should help security people do a better job of dealing with these sorts of attacks.

• viruses
• trojan horses
• spyware
• rootkits
• malware
• worms
• bombs

In the not too distant past pathogens needed to be physically distributed between machines almost always without the knowledge of the person doing the distribution.  This was usually done through floppy diskettes or other removable media.  This has changed considerably now that the Internet is getting more and more widespread.

Protection.  Protection from pathogens is usually based on good user education.  But it also requires that software patches provided by vendors be installed diligently.  What can happen is that some sort of flaw and/or vulnerability gets discovered by the user community.  After this one more than hopes that the vendors will come up with the installable patches to provide protection.

There are also a number of vendors who provide security software such as the following

• McAfee
• Symantec/Norton

Keeping this software up to date and performing regular maintenance and scanning helps greatly reduce the risks of computers being attacked through pathogens.