Anyone who installs an app on their smartphone is asked shortly afterwards what permissions the app is allowed to have. It often needs them to work properly. But this does not always apply. Smartphone users should therefore look closely.
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Apps can be practical helpers in everyday life – image editing, the barcode scanner or the navigation application. But app developers are in most cases not selfless gift givers, but want to profit from the applications. For example, advertising banners are displayed, which also not infrequently show exactly what users have typed into a search engine shortly beforehand or are tuned to the location. Because the applications collect data, which can be a lucrative business.
"It is important to pay attention to which permissions you grant the app", says Markus Merkle of the portal "Handysektor.en". "That a flashlight app wants to access the camera is logical – after all, it needs to be able to control the flash." Nevertheless, this app theoretically also has the right to use other functions of the camera. "That doesn’t mean it will necessarily do so", so Merkle. "But there is never absolute security."
160 different permissions
Apps can request a total of 160 different permissions. From the request to determine the storage location to accessing the address book, WLAN settings and other sensitive data. "It’s best to check before downloading an app whether the required permissions even fit the function", says Merkle.
You should also take a close look at the manufacturer of an app. A serious developer will rarely take the risk of damaging his reputation by dubious behavior of his program. "But here, too, you can’t say across the board that only smaller programmers "tap" data per se, says Merkle. Indices such as download numbers or ratings in the app stores can also give an impression of whether an app really only serves the purpose it is supposed to. Merkle recommends researching problems with the corresponding app or reading up on it in technical journals if you’re unsure.
Choose a different app if you feel uncomfortable
"If the permissions an app requires somehow make me uncomfortable, I should look for an alternative", says Alexander Spier of the computer magazine "c’t". Especially for free apps, there are usually other offers. A look at the user ratings of an app can also help. "Especially the negative comments can be quite helpful here, but should also not act as the only decision-making aid."
However, some permissions could be granted with little concern. "Access to memory is mostly unproblematic, internet access is also rather harmless", says the editor. With everything else you should be careful. "Of course it makes sense that a weather app can access the location to deliver the forecast. However, it may then do so permanently." The optimal solution would be to revoke this authorization after each use of the application – but no one would seriously consider this because of the effort involved.
Be careful, especially with older devices
Especially on older devices up to Android version 5.1 (Lollypop), you have to be careful and read exactly which areas of the smartphone the app wants to use before installing it, says Spier. "Older Android versions only grant general access and do not differentiate between individual areas." If one refuses these accesses, one renounces at the same time an installation.
Merkle, however, has at least one tip on how to keep your phone free of old apps. "I regularly check which apps I still use at all. Anything that hasn’t been opened in two weeks is deleted by me." This way, you don’t prevent misuse of data in general, but you can prevent an app that is unused anyway from exploiting its permissions.
Be careful when accessing SMS
App developer Tim Christmann especially warns against accessing SMS: "You often get security codes for various answers sent to you via SMS. So if an app has access to it, the gap is pre-programmed." This also applies to bank TANs. Often the value of the data and the benefit of the app would be out of proportion for the consumer. "Large providers like Google are more likely to evaluate the data for their own purposes. But with smaller providers, misuse of data can certainly lead to extortion", says Christmann.
Also, not every app offer that seems serious at first is really safe. "Some cleverly fake the names and logos of well-known manufacturers so that at first, quick glance, you might think it’s actually a well-known company."