Capitalizing on the popularity of the iPad -- an estimated one million have been sold since it made its debut at the beginning of April -- malware creators are targeting the device to spread a new threat, according to BitDefender.

The security vendor is reporting that PC users are receiving emails promising to keep iPad software updated "for best performance, newer features and security." The email provides a link and instructs iPad users to download the latest version of iTunes software to their PCs as a preliminary step to update their iPad software. The downloaded page users are directed is actually a hoax site that infects their machine with malware identified by BitDefender as Backdoor.Bifrose.AADY.

This piece of malicious code "inadvertently downloaded injects itself in to the explorer.exe process and opens up a backdoor that allows unauthorized access to and control over the affected system,'' according to BitDefender.

Backdoor.Bifrose.AADY also attempts to read the keys and serial numbers of the different software applications installed on the affected computer, while also logging the passwords to the victim's ICQ, Messenger, POP3 mail accounts, and protected storage, the vendor reports. Apple has not yet released an update for the iPad.

Mac users are not affected by this piece of malware, BitDefender emphasizes. A senior researcher for BitDefender calls the prank "clever," noting that it was purposely aimed at Windows users who have bought an iPad and don't run a security product. If the malware authors were able to target Mac customers, "it would have spread like wildfire," the researcher says.

For now, the iPad itself hasn't been targeted by hackers and malicious code.

PC users are being urged to only download files for the iPad from Apple's official Web site; install and activate a reliable firewall and anti-malware and spam filter; update security software frequently for the latest virus definitions; run a complete anti-malware scan before opening or copying any files; and scan your system frequently.

Apple also recently warned about a Trojan virus being spread to users interested in breaking their iPhones, with malware authors sending out spam email promising a simple unlock. Once users click on the link, they are redirected to a Web site where they can download software, which hijacks the computer's DNS requests to their own server.

Apple was planning to launch the iPad in Britain at the end of April, but now says it will begin taking pre-orders in early May.