Don't Get Turned into a Spam Zombie

Nearly all the experts agree. The increase in spamming activity over the last year or so is mostly the result of networks of zombie computers known as "botnets."

A zombie is a single computer that's been taken control of remotely either by a hacker, or another computer. Zombies are commonly used to send spam, but may also be used for other malicious acts. Usually computers become zombies by automated hacking attempts perpetrated by other zombie systems.

Often the owner of the zombie computer isn't aware anything is wrong. They might notice excess network activity or general system slowness. However, systems that are vulnerable to being hacked are usually not well maintained - so poor system performance may not hit the owner as cause for alarm.

A botnet is a collection of zombie systems all controlled by a single entity. The "owner" of the botnet might use it themselves to send junk email or launch a denial of service attack against a website they don't like.

There is also a growing black market for botnet rentals. Anyone who has the right contacts and money can control hundreds of thousands of computers against the will of their owners.

At least one botnet was discovered to contain 1.5 million systems; it's plausible that even larger ones exist.

Botnets are "logical" networks of systems in that they are all controlled by a single entity. They however, don't have to reside on the same part of the internet or even within the same part of the world.

This makes spam sent by botnets especially difficult for email filtering software to identify and delete using traditional blacklists due to the vast number of individual sending computers. Many newer DNS blacklists like the CBL track millions of individual IP addresses in an effort to minimize spam from botnets.

So how can you avoid becoming a zombie?

Use a hardware firewall
That $50 device you can pickup at your local technology store can be surprisingly effective. By putting your computer on a "private" network - you avoid being exposed to most direct hacking attempts. If you're not sure if you're already running a firewall (and don't know how to find out) - installing a secondary one won't hurt.

A software firewall such as the one included with Windows XP can be useful, but a hardware firewall is generally more secure and less likely to be inadvertently (or intentionally) disabled.

Keep your system up to date
Go to http://www.windowsupdate.com and make sure you're running all the latest patches. Unpatched systems can quickly fall victim to hackers.

Use FireFox, not Internet Explorer when surfing "questionable" websites
Internet Explorer 7.0 is better than 6.0 from a security standpoint, but still has some serious issues. Get FireFox.

Scan your system for malicious software
Ad-aware is free for personal use. Microsoft's Antispyware product is also free and may be worth a look.

Don't install software you're unsure of
Free games and file-sharing software should be considered highly suspicious. Any website that wants you to install software to view "videos" should be avoided like the plague. In general, "active-x controls" are bad news and should not be installed.

Software that is downloaded from file-sharing networks is very frequently infected with malicious code. If you're looking to download free or trial software - do so from a major site that you trust.

Don't open those attachments
Get an email with an attachment you weren't expecting? Treat it the same way you would a ticking package with wires coming out of it. Don't open it - it will end in tears.

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