A security researcher has developed what he says is the first Trojan malware for RIM's BlackBerry email device.

The software, which was demonstrated at the Defcon hacker conference over the weekend, appears to be a free tic-tac-toe download. Once downloaded, however, it works with another piece of code, called BBProxy, which can be used to attack vulnerable machines within the corporate network.

Jesse D'Aguanno plans to make the BBProxy software, but not the Trojan horse code, available on his company's website within the next few days. It will be available here.

The BlackBerry hack was written to show that while these devices are often not treated with the same concern as PCs, they can be equally dangerous, said D'Aguanno, director of professional services and research at Praetorian.

When users think of the BlackBerry's security, they are too focused on protecting the device's data, and tend to ignore its networking capabilities, D'Aguanno explained. "It's a computer that has constant access to your internal network," he said.

After reviewing his research, RIM published two documents describing how to configure BlackBerry Enterprise Servers so they are not vulnerable to this attack.

RIM said attacks such as D'Aguanno's were possible on any mobile device and that they could be avoided by properly configuring the BlackBerry Enterprise Server.

"The IT policy settings for preventing malware exploits are built into the BlackBerry Enterprise Server software and can be set by the administrator," RIM said in a statement. The firm's white papers on the subject can be found here.

One security expert agreed that users tend to overlook the capabilities of machines such as the BlackBerry.

"When people install these types of devices they are very casual about the policy around the device," said Paul Henry, vice-president of strategic accounts at Secure Computing. "There's the assumption that because they're encrypted, they have to be secure.

"It all points to a much bigger problem. For whatever reason, as soon as a device is put into the marketplace with encryption being used, everybody forgets about the endpoints."