Malware threats to the Android OS are "increasing in prevalence and sophistication," said lookout Mobile Security, which just released its 2011 Mobile Threat Report

lookout published the following findings:

- Android users are two and a half times as likely to encounter malware today than 6 months ago

- Three out of ten Android owners are likely to encounter a web-based threat on their device each year

- An estimated half million to one million people were affected by Android malware in the first half of 2011

- Android apps infected with malware went from 80 apps in January to over 400 apps cumulative in June 2011 (graphic below)

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- Worldwide, the likelihood of encountering malware varies from less than 1% to more than 4% depending on country (graphic below)

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lookout said criminals have become more sophisticated and creative at tricking smartphone users; in addition to selling malicious apps on the Android Market, they are also tricking users through "Malvertising" and "Update Attacks."

In "Malvertising," users are directed by mobile advertisements to malicious websites.  In "Update Attacks," criminals release a legitimate app and then roll out a malicious update.

lookout said most attackers are trying to score an immediate monetary payout.  However, due to the "sheer amount of personal information stored in our smartphones," they can possibly exploit the information in other "creative" ways.