In a glimpse of the dark side of the ever-increasing sophistication of our favorite gadgets, there are reports of a Trojan that attacks Nokia (NYSE:NOK) smartphones running the Symbian operating system.

Operating system? Isn't that for computers? If you're thinking something along those lines -- I'm waving at you, Mom -- welcome to the future.

In this world of gadgetal convergence, smarter phones are computers. Witness palmOne's (NASDAQ:PLMO) popular Treo line, or Hewlett-Packard's (NYSE:HPQ) iPaq PDA/phone that runs a mini version of Microsoft (NASDAQ:MSFT) Windows.

Symbian, a company founded by Nokia in partnership with Motorola (NYSE:MOT) and Ericsson, among others, produces the competing OS used on millions of new-generation handsets -- and is even working with Intel (NASDAQ:INTC) on future projects. As the most widely distributed advanced phone OS, Symbian will bear the brunt of many of these attacks.

So it's no surprise that some putz came up with a malicious program to try to wreak a bit of havoc. The program in question is not a virus or worm -- unlike a previous, annoying bit of code. This one cannot "infect" users' phones without their complicity in the process. It masquerades as a free add-on, but when installed replaces icons with a skull and crossbones and keeps the afflicted phone -- so far, just the Nokia 7610 -- from doing anything but sending or receiving calls. Like most malicious code, it can be remedied with tools widely available on the Internet.

Only one thing is certain: This won't be the last time we hear about something like this. Investors in the brave new world will need to consider how firms respond to such threats, as the negative PR from repeated episodes can begin to erode consumer confidence and push buyers toward alternatives that seem safer. Think of Apple's (NASDAQ:AAPL) continuing efforts to present its product as a "safer" OS.

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Seth Jayson carries a worm-free Nokia phone and, at the time of publication, he had long positions in Nokia, but no position in any other company mentioned. View his stock holdings and Fool profile here. Fool rules are here.