RAT, Commercial RAT, Nuker, Mail Bomber, IRC War. No, these are not the handles of players in some ultra-violent computer game, or the names of the latest viruses to hit the Internet. Rather, they are "pests," and they are a growing security problem, according to the folks at PestPatrol Inc., which this week released a list of the most prevalent pests.

As you can probably surmise, PestPatrol makes a tool for getting rid of these pests, which for the most part are self-contained applications, according to Pete Cafarchio, vice president of business development for PestPatrol. That's what makes them different from viruses, which are mere portions of code, or in the case of worms, scripts that replicate.

"Pests are actual applications that lie low and are dormant," Cafarchio says, noting that antivirus software won't catch most forms of pests. "To remove them you need to kill the files."

Unlike viruses, pests don't generally have the capability to spread on their own. Rather, they come attached to email messages or users unwittingly download them from Web sites, via instant messaging or through peer-to-peer systems. The most common type of pest, known as adware, is contracted from simple Web browsing. A user may be prompted by a popup message to download some freeware, such as a game, which comes with adware code attached. The code then later dishes up more pop-up ads, on a context-sensitive basis.

While adware is simply annoying, other pests can be destructive or dangerous, such as keystroke loggers that file away every keystroke a user makes and periodically sends the log to whoever installed the code.

"I just talked to a Brazilian bank that's losing significant money because of key loggers. Some of its customers are being compromised. It's a real problem," Cafarchio says, noting some newer forms of worms try to install key loggers.

One thing pests do have in common with viruses is that they are growing in number. PestPatrol has been compiling data from its 200,000 users worldwide from some time, but this week started releasing the results in a monthly Pest Prevalence Report.

PestPatrol says it found 90 new pests in January alone. Among the top types of pests the company found are:

  • Adware
  • Spyware and spyware cookies -- Programs or cookies that collect information on your browsing habits and ship it to advertisers.
  • Browser helper object -- A potentially helpful browser utility that also collects information on the user for advertisers.
  • Dialer -- A program that disconnects a user's dial-up connection, then mutes out the modem tones and dials a 900 number or expensive foreign number, to generate revenue for the owners of the lines.
  • Hijacker -- Changes the home page on the user's Web browser. User has to find and delete the pest in order to change it back.
  • RAT (Remote access trojan) -- Programs such as Back Orifice and Sub-Seven that gives an intruder complete control over a target system, unbeknownst to the target's owner.

    • For the complete list, go to this PestPatrol Web page.