PDAs as “simple devices” has left many owners so as corporate networks vulnerable to attack. Not only can the PDAs themselves be compromised, but PDAs can also be used as trojans to attack a network. 

Attacking a PDA is not as easy as attacking a PC. Because the operating system is in ROM, PDAs tend to be unique, and the art of exploiting PDAs is relatively new. But if a hacker is willing to accept these limitations and is sufficiently obsessed, there are a number of ways that PDAs can be exploited.
 
PDAs running Windows are compromised, using cabinet files and the autorun feature of removable media cards to introduce malicious programs. Pocket Internet Explorer can be used to trick users into revealing personal information. Additionally, Soft Input Panel (SIP) that substitutes for a hardware keyboard on Pocket PCs can easily be replaced by a seemingly identical program that logs keystrokes.

Related Articles:
Introduction to PDA & Hadheld Security
Ways to Secure your PDA and Handheld