Some advertising networks have been secretly collecting smartphone application users’ personal details over the past year and now have access to millions of smartphones globally, according to U.S.-based mobile security firm Lookout Inc., Reuters reported.

These unregulated practices are on the rise, Lookout said today as it unveiled the first industry guidelines on how app developers and advertisers could avoid raising consumer angst.

Some of the most advanced mobile viruses can even create charges to consumers’ phone bills or crash the devices.

“Aggressive ad networks are much more prevalent than malicious applications. It is the most prevalent mobile privacy issue that exists,” Kevin Mahaffey, Lookout’s technology chief and co-founder, told Reuters.

More than 80 million apps have been downloaded with a form of invasive ads that can take data from phones or install software without users’ knowledge.

Some more aggressive networks collect users email addresses or phone numbers without permission, while others install icons to home screens, track users’ whereabouts or push ads to notification bar.

Mobile devices have so far had limited appeal for writers of viruses or other malware due to numerous small platforms and limited financial gains, but during the first quarter, the amount of malware on the popular Android platform jumped to 7,000 from 600, according to Intel Corp.’s security software arm McAfee.