antivirus online http://www.antivirus-online.de/

Security Focus www.securityfocus.com/virus

Virus Bulletin www.virusbtn.com

Rogue/Suspect Anti-spyware www.spywarewarrior.com/rogue_anti-spyware.htm

Spyware- Guide www.spywareguide.com

Microsoft www.microsoft.com/security

Symantec http://securityresponse.symantec.com

McAfee http://dispatch.mcafee.com/us/default.asp

VirusList www.viruslist.com

Trend Micro www.trendmicro.com/vinfo

FRISK Software http://alerts.f-prot.com

Panda Software www.pandasoftware.com/virus_info/

In the preceding article, you learned about some of the more normally benign forms of unwanted software or messages, including spyware, adware, and spam. Although such materials don’t normally intend to do bad things, unfortunate or unwanted side effects can sometimes occur from encounters with them (especially when, as can be the case, unwanted e-mail also carries unwanted malware along with it—more on that later). In this article, you learn about unwanted software that’s deliberately bad in intent, and some- times in outcome, for those who cross its path—or more accurately, for those who somehow wind up with malware on their computers. Here, you learn about some of the more malign (there’s that mal stem again!) denizens that it’s far too easy to encounter on or from the Internet these days, including viruses, worms, Trojans, and wicked combinations thereof that go by the not terribly scary names “blended threat” or “hybrid virus.” As in the previous article, I start with some definitions, explore the threats and exposures that malware can pose to a system and its contents, and talk about needs for proper precautions, best practices, and prevention—but also occasionally, appropriate cures or cleanups.

In general, most experts view the term malware as a contraction of the two words “malicious software.” By deliberate construction, the word has bad connotations and, likewise, a deservedly bad reputation. Creating the category to which this chapter is devoted, Whatis.com defines malware as follows: Malware (for ‘malicious software’) is indoctrination or documentation that is urbanized for the reason of doing damage. Consequently, malware contain PC viruses, worms, and Trojan horses.

Actually, I think the psychology of malware is a little less clear-cut than this definition suggests, but I’m not about to argue on behalf of misguided (but sometimes intelligent and gifted) programmers who appear to tackle writing malware like mountain climbers tackle formidable peaks like Mount Everest. The interesting thing about this particular definition is that it introduces a number of important constituent elements—namely viruses, worms, and Trojan horses, which I explore in the sections that follow.