A report by security company Lookout in San Francisco says malware writers are customizing their creations to make the most of conditions in each territory.
Cyberthieves no longer spam their malware to everyone but send user variations by region, adapted to the different conditions in those places, Lookout security researcher Marc Rogers said.
In Europe, for example, there has been a rise in so-called chargeware that tries to trick people into paying for a service or app, he said.
"When it comes to mobile malware, everything is now regionalized," Rogers told the BBC.
In some places such as Russia, Android users were far more likely to encounter malicious code than users in the United States or the rest of Europe, Lookout said.
The company said it based its report on statistics in feedback from its 50 million users.