A threat by any other name...

We're confronted with a host of cryptic, technical, and whimsical handles—worms and viruses, Trojan horses, blended threats. Nimda, Bugbear, Sobig, WarPigs. It can all be a bit overwhelming. The good news is most of these threats are less enigmatic than their names imply, and rest assured Symantec has developed advanced technologies to defend against them.

Beating the virtual flu
Probably the best known security threat is the computer virus. The name, although disquieting, is apropos. In nature, viruses are microorganisms capable of growth and multiplication in living cells. They also cause sickness.

Likewise, computer viruses, which thrive and replicate within host computer files, are capable of doing harm to your PC or Mac. Moreover, just as humans contract viruses through contact with other infected persons, computers contract viruses through contact with infected files—whether they encounter those files as email attachments, Web downloads, or on floppy disks.

The analogy stretches even further. In the organic world, we take steps to avoid spreading and catching viruses like the flu. We get vaccinated, pay attention to hygiene, and avoid close contact with others when we're sick. You can also act to prevent computer virus infections. For example, you can use trusted virus protection software like Norton AntiVirus™ to detect, contain, and eradicate infected files before they damage your computer. You can run Symantec LiveUpdate™ on a regular basis.

LiveUpdate acts as a kind of booster shot, keeping your virus protection up to date. And, should your computer become infected, you can avoid spreading viruses to others by limiting communications with other computers. Fortunately, these measures are more successful in the digital world than they are in nature. We still haven't found a cure for the common cold, but we have developed the means to ward off most computer viruses.

Those clever Greeks
The famed Trojan horse. According to myth, Odysseus and a group of his soldiers piled into a giant, wooden horse and then had the horse presented to the city of Troy. The Trojans, intrigued by the massive structure, brought it inside the city walls. The Greeks thereby infiltrated Troy and defeated the Trojans in a surprise attack. The image endures. A Trojan horse has come to stand for anything intended to defeat or subvert from within.

In computer parlance, Trojan horses are malicious programs disguised as something benign. They've been known to pose as games, utilities, and email attachments. Once opened, Trojan horses act differently than expected. Some merely annoy, sending emails to everyone in your address book. Others do serious damage, to the point of stealing passwords and data files.

As with viruses, there are ways to protect yourself from Trojan horses. Defenses like Norton Internet Security™ are able to detect and destroy these subversive programs before they affect your computer. Norton Internet Security is ever-vigilant, scanning your drives for known Trojan horse programs and employing LiveUpdate to inform itself about the latest Trojan horse threats. So, take a lesson from Greek myth. Secure your computer with Symantec software, and it's unlikely you'll find yourself hoodwinked like those ill-fated Trojans.

Digging worms
Worms. Now they have one of the juiciest names going. Do they live in the digital underground? Are they virtual fish bait? Do they poke their heads from shiny, red computer apples. Well, no. Their name actually derives from John Brunner's science fiction novel, The Shockwave Rider. In the novel, one of Brunner's characters uses a self-propagating program to distribute information from computer to computer. He called that program a worm. It's still the ability to self-propagate that separates worms from viruses. Worms can spread over a network independently, without the need for host files. Viruses cannot.

Like viruses, however, worms are small programs that can replicate and move from system to system, and although many are benign, some are capable of causing damage to your system. In fact, there's been a recent spate of advanced, malicious worms directed at both home users and corporate networks. Some of these worms—one of them goes by the warm-and-fuzzy moniker, Bugbear—attempt to shut down your personal firewall and virus protection software.

In response to advances in worm design, better worm defenses have evolved. In turn, worm programmers have become more clever and aggressive, creating a kind of escalating cycle of one-upmanship. For example, there was a time when many worms would take over mail programs and use those programs to send themselves to other machines. In response, mail programs were patched to prevent takeover. Now worms like Bugbear have their own email engines, and they can simply email themselves. Some also contain back doors, which allow programmers to access and manipulate their worms after they've been deployed. Security companies, in response to these evolutions, continue to improve their own security measures.

Symantec, however, has taken things a step further and attempted to disrupt the escalating cycle of innovation and response. Norton AntiVirus contains Worm Blocking, a special tool that can anticipate how worms will evolve and block them even before a definition of the worm has been developed. This kind of protection, used in concert with Symantec's time-proven antivirus engine, is at the cutting edge of worm defense.

Blended threats
In recent years, a new security category has emerged: the blended threat. Blended threats exhibit a combination of virus, worm, and Trojan horse characteristics. Because blended threats have more than one way to propagate and cause damage, they are particularly nasty and difficult to contain. Nimda is perhaps the best-known blended threat. Nimda, which is "admin" spelled backwards, is a mass-mailing program that uses multiple methods to distribute itself. It was discovered in 2001, and although it affected most kinds of Windows operating systems, it specifically targeted corporate Web servers running Microsoft IIS.

Since Nimda appeared, blended threats have been on the rise and continue to evolve. One of the most recent blended threats is Klez and its iterations. Klez not only distributes itself through multiple means, but also uses clever personal mail message subjects to fool users into opening infected attachments. Some of its variants have been known to damage operating systems beyond repair.

To counter blended threats, you need to take a comprehensive security approach. Fortunately, Symantec combines its most powerful tools in one convenient package. Norton Internet Security includes Norton™ Personal Firewall, Norton AntiVirus, and a number of other newly-developed security tools. It's equipped to combat all sorts of viruses, Trojan horses, and worms, as well as their variously-named hybrids. So, don't let the imaginative and wide-ranging jargon of computer security leave you confused and uncertain. A threat by any other name is just a threat, and you can count on Symantec to decipher each one and to meet it on head-on.