Malware developers are targeting Android mobile devices more than ever, indicating Google's open mobile platform may draw even more attacks as the mobile industry keeps growing. One-third of all mobile users, Android or Apple, may come across an unsafe link this year, according to a report by Lookout, a smartphone security company that monitors apps. Android users are particularly vulnerable, and are twice as likely to be hit with malware now as they were six months ago. Up a million Android-devices may be infected with malware this year.

Also, the number of infected Android applications is growing, according to Lookout, from 80 Android apps in January to more than 400 applications by June. The threats can be either application-based or Web-based. Application-based threats come through malware and spyware, while Web-based attacks are typically through phishing schemes, browser exploits and downloads, said Lookout.

According to Lookout, which provides protection software of its own, app-based threats on Android's Market are increasing, and "attackers are using new distribution techniques, such as malvertising and upgrade attacks."

With Android's sales growing, users will likely see even more malware pop up on their phones and tablets. More than 500,000 units activated every day, and those numbers are expected to keep growing.

The app-based malware attacks may also continue to grow as people continue to download more apps onto their phones. Earlier this year, malware hit more than 250,000 Android users when they downloaded apps infected with DroidDream, a program that sends a phone's ID number to a server for others to access.

While Apple users have had some problems with infected apps, the problem is not as widespread because the Cupertino, Calif.-based company more carefully vets the apps sold in its App Store.

On the other hand, Android devices are inviting target for hackers. Android Market is much more open in terms of submitting apps, leaving it wide open for hackers to install malicious code.

As malware attacks keep increasing, all mobile device users will need to use judgment when downloading software and apps onto their phones, just as they had learned to do on their personal computers. The problem isn't likely to go away soon, and will likely increase as more mobile devices come on the market and malware developers become more sophisticated with their work.