More than a third of smartphone apps can track user location, according to a study based on an analysis of more than 800,000 Android applications.

Analysis of 836,021 Play Store Android applications by net security firm BitDefender also revealed that more than one in 20 (5 per cent) of Android smartphone apps can locate and open private photographs on smartphones.

Other privacy concerns include apps that divulge email addresses over the internet and either leak address books or phone logs, according to the Romanian security firm. One in 30 (3 per cent) of the apps analysed can divulge email addresses over the internet. Meanwhiel, 1,749 uploaded the address over an encrypted connection and a further 1,661 did so over an unencrypted connection where traffic can be easily harvested.

Almost 10 per cent of apps tested included permissions to read contact lists. Many have a legitimate need for this data but others are clearly intrusive.

Unauthorised permissions may provide access to a device’s location, address books, telephone logs and geographic data from photos uploaded to the mobile versions of social networking sites.

Facebook and Twitter both clear photos of metadata before publication, but a third party could duplicate the info as it travels across a carrier’s mobile network to be stored for further processing.

Similar problems crop up when third-party ad providers take data from the phone to use for targeted advertisements. BitDefender's study is at least in part designed to promote its Clueful mobile app, which displays permissions required by each app and helps with privacy decisions.

The Romanian security firm's figures don't cover iOS apps. However a separate study by cloud security firm Zscalar into privacy issue with iOS apps found that 96 per cent of iOS apps require email, address book (92 per cent), location (84 per cent), camera (52 per cent), calendar (32 per cent) permissions.

Zscalar analysed the top 25 most popular iOS apps across five categories.

"The bulk of apps are free, but developers need to turn a profit somehow," explained Michael Sutton, VP of security research for Zscaler. "That's generally done by embedding advertising and sharing metrics with advertisers about user behaviour, better enabling advertisers to deliver targeted apps.

"While some may be fine with sharing data in order to receive ads targeted to their interests, others see it as a privacy concern and as we've recently seen, spy agencies, such as the NSA are taking advantage of the data shared by mobile applications."

Sutton credited Apple at least with acting to address the problem.

"While Apple in particular has started cracking down on more egregious data leakage issues such as collecting geo-location data or contact information in violation of their developer guidelines and has added features to limit advertiser tracking, both iOS and Android still permit apps to share a significant amount of data about users and their devices." ®