Backdoor.Bardor.A, the first alleged Windows CE backdoor Trojan horse, isn't much of a threat, says Chris Auld, managing director of mobility software specialists Kognition.
However, it is a precursor to more serious mobile worms and viruses, he says.
"It's not dangerous and because of that I haven't looked at it in great detail, but going forward, there's a reasonable degree of risk in PDAs."
It's their networking capability that makes PDAs so vulnerable, he says.
"With most new devices having networking functionality of some sort, we'll see more worms on mobile devices and not just on Windows CE, but on Symbian as well."
When virus writers realise the full potential of mobile devices, expect nastier worms and viruses than Backdor.Bardor.A, he says.
"Something they can potentially do is write or overwrite some of the information stored in the read-only memory and they could potentially destroy the device as far as use is concerned.
"Users may have to re-flash the device."
Another possible means of attack is writing a virus to the ROM "such that when the user does a reset it could, as the device is started up, reinstall the virus out of the ROM.
"There are things that present themselves in the mobility space that don't in the desktop-server space, but I don't see much trouble for the mobile platforms until virus writers start looking outside the box."
However, it's not a case of PDA users having to helplessly wait and see what horrors are unleashed by virus writers, he says, as there are ways of protecting against the coming onslaught.
"We need to ensure platforms are carefully secured against third party code and future platforms will have functionality for restricting third party operators."
Backdoor.Bardor.A, aka Backdoor.WinCE.Brador.a, was discovered by Symantec and Kaspersky Labs and is rated one, the least serious rating, on Symantec's 1-5 threat level scale.
Once on a mobile device, Brador copies itself to the svchost.exe file in the Windows autorun folder and takes control of the system after a restart.
Symantec Security Response senior manager Oliver Friedrichs says it emails the attacker your IP address, and the attacker "can then connect back, access the back door, look at your files, download the files or even upload other malicious code."