Security consultants @stake have added to the weight of expert opinion that business use of PDAs such as a Palm Pilot may be a security risk.

@stake, a US-based security consultant, has written a piece of software code that can zap passwords off targeted Palm Pilots through taking advantage of the PDA's hotsync function. Hotsync is used to transfer data between the user's PC and a Palm Pilot.

Called Notsync, the code fools the targeted Palm Pilot into thinking it is talking to the user's desktop computer, rather than a hacker's PDA. The hacker then downloads the target's password via the target machine's infrared port.

Infrared ports have a range of 50cm to 100cm, but @stake said amplifying systems can increase the range threefold.

The consultant said its Notsync code could be written by any competent hacker, and is warning firms to make sure they know what company information is being held on their employees' PDAs.

Notsync's author, Mudge, vice president of R&D at @Stake, said: "They are completely vulnerable."

According to handheld manufacturer Psion, 70 per cent of IT managers are concerned about how to integrate mobile working and applications into office networks. The firm said around 75,000 people received handhelds for Christmas.

@stake believes the line between personal and corporate information on mobile technology is becoming blurred, and that this may put sensitive data at risk through exposing links to corporate networks.

The firm believes that users often use the same password on their PCs as other devices, thus exposing the corporate LAN from the Palm Pilot. It says organisations should make it standard practice that employees use different passwords for their various computers.

Mudge said: "Wireless is extending the frontier of the corporate network and lowering the level of security, while magnifying the problems."But he added: "We're not trying to scare anyone here. We're trying to stress that companies must adopt a strategic approach to wireless security.

"There's an opportunity with wireless to accentuate security and have it thought of as an enabling activity rather than as an after-the-fact reaction."

"Companies may not need to increase their security budget," said Mudge, "but they do need to focus more intensely on where they are spending. They need to know which data is sensitive to them, where it is and what it's doing."