Anti-virus company Bitdefender says one in five iPhone apps coudl access data from yoru address book. the security company analysed approximately 65,000 of the more popular apps in the Apple App Store to reach its conclusion.
The months-long Bitdefender study found that some 41.4 per cent of the apps analysed can track a user's location.
"This means that that most iPhone owners are likely to have at least one app on their device capable of knowing where they are," Bitdefender's chief security researcher, Catalin Cosoi, said.
The other revelation was that only 57.5 per cent of apps encrypt stored data. "With more than one in three apps storing your data without encrypting it, this potentially places the user's data at risk after accessing it," Cosoi said.
The low occurrence of encryption on iOS apps and prevalence of location tracking was described by Cosoi as being "worrying."
"Without notification of what an app accesses, it's difficult to control what information users give up," he said.
"We see a worrying landscape of poor user data encryption, prevalent location tracking and silent, unjustified, address book access."
Although certain apps use these types of privileges to function, the concern for Cosoi stems from the apps that have "no obvious use" for the data that may have collected.
He adds that apps on the App Store only ask for permission to access location--related services, but not when accessing the address book or other functions on the device. As for what use the location and address book information could have to companies, Cosoi says that this type of information can be sold and used for putting together marketing campaigns.
"Location tracking used in contextual ads that display based on geo-position is highly controversial, yet common," he said.
Bitdefender's study only covered a sample size of 65,000 of the "more popular" apps in the App Store and did not investigate all of available apps that are currently available.
Cosoi conceded that the numbers and ratios "may change" if the apps in the entire App Store were analysed.
Other key findings made by Bitdefender in the survey were that 30.7 per cent of apps were found to display ads and 16.4 per cent connected to Facebook.