Security comparison: Android versus Apple

Now, Jin Han and co-workers at the A*STAR Institute for Infocomm Research and Singapore Management University have conducted the first systematic comparison of the two biggest operating systems in mobile software1 -- Apple's iOS and Google's Android. The two companies take markedly different approaches to security.

Apple famously maintains complete control over iOS security, promising that all applications are thoroughly screened before release and security patches are smoothly applied across all their phones. However, malicious software has appeared in the iTunes store.

Android, in contrast, displays everything that an application will need to access so that users can decide themselves whether to go ahead with an installation. Some critics argue that handing such control to unqualified users could present a security risk in itself.

To compare these two security models, Han and co-workers identified 1,300 popular applications that work identically on both iOS and Android. These applications, such as Facebook, often access code libraries on smartphones called security-sensitive application programing interfaces (SS-APIs), which provide private user data or grant control over devices such as the camera.

"We needed to establish a fair baseline for the security comparison between Android and iOS," says Han. "We achieved this goal by examining the SS-API usage of cross-platform applications."

The researchers found that 73% of iOS applications, especially advertising and analytical code, consistently accessed more SS-APIs than their counterparts on Android. Additionally, the SS-APIs invoked by iOS tended to be those providing access to sensitive resources such as user contacts.

The results imply that by allowing users to control permissions, Android may be better at preventing stealthy applications from getting hold of private information. Notably, Android also intentionally avoids using SS-APIs if non-security-sensitive APIs can be used to achieve the same functions.

To avoid jumping to conclusions about the risk to Apple users from the iOS process, Han urges caution in interpreting the results. "Mobile platforms are constantly evolving," he says. "Our experiments were mainly conducted on iOS 5, but iOS 6 has enhanced its privacy protection so that users will be notified when an app is trying to access their contacts, calendar, photos or reminders. This may encourage developers to modify their apps so that they access less private data."

The A*STAR-affiliated researchers contributing to this research are from the Institute for Infocomm Research.

Article reference: Han, J., Yan, Q., Gao, D., Zhou, J. & Deng, R. Comparing mobile privacy protection through cross-platform applications. The 20th Annual Network & Distributed System Security Symposium, 26 February 2013.