What Do Cell Phone Apps Use Your Contact List For

Have you ever given an app on your phone permission to do something without a second thought? Many people grant even sensitive permissions, like access to your camera, microphone, and location, as soon as they appear.

But that's a risky way to use your phone. Let's look at the most dangerous types of mobile permissions, and the ways that an app could abuse them to steal information about you.

A Quick Refresher on Mobile Permissions

We should quickly review how permissions work before we proceed.

On both Android and iPhone, apps require permissions to access sensitive data on your phone. If a developer makes an app that relies on having your contacts, for example, they must add a permission request for that access into the app's code.

When you grant an app permission to do something, it has that permission until you disable it. It won't ask you every time to authorize an action. However, some sensitive permissions have the option to allow them only when you're using the app (discussed below). And in some cases, you can set certain permissions to ask you every time you open the app.

Android Permissions Explained

On modern versions of Android, you can grant or remove access to permissions individually. After you install a new app, you'll see a popup asking you to give permission for the app to get permissions as it needs them.

For example, say you download a new SMS app that has an in-app camera function to send quick pictures. The first time you hit this, the app will ask permission to access your camera. If you say No, then the app simply can't use that functionality.

You can change permission settings for apps on Android by going to Settings > Apps > See all X apps. Choose an app from the list, then tap the Permissions field to see all the permissions that the app has and doesn't have. Tap one to change it.

To instead see all apps grouped by the types of permissions they use, visit Settings > Privacy > Permission manager. Here you'll see permissions like Camera and Location; tap one to see the apps that have the permission allowed or declined.

Note that ancient Android versions (Android 5 Lollipop and older), use an all-or-nothing permissions system. On these platforms, when you install an app from Google Play, it shows a list of permissions that the app wants. If you don't want to grant access to one of those permissions, your only option (aside from rooting) is not using the app.

Some old Android apps that haven't been updated for modern versions of Android still use this upfront permissions style. You can revoke individual permissions for such apps on modern Android versions, but doing so might break them.

iPhone Permissions Explained

A similar permission system exists on iPhone. Once you download an app, it will prompt you for various permissions whenever it needs them. You decide whether to enable each app permission individually and can revoke them anytime.

Head to Settings > Privacy to see a list of all permissions, then tap one to see the apps that have requested it. Use the toggles to approve or decline each permission. If you'd rather look at permissions on a per-app basis, scroll down on the main Settings page and tap an app to see everything it has requested.

Now, let's look at sensitive smartphone permissions that you must be careful with on both Android and iPhone.

1. Microphone

It's no surprise when a voice recording app needs access to your microphone. But how about when a free game that you just installed asks for this permission? If it seems a bit fishy, that's because it is.

In 2017, The New York Times reported that hundreds of games on Google Play, and some on the App Store, are integrated with a software called Alphonso Automated Content Recognition. This was later expanded on by Sarvesh Mathi on Medium in 2019.

Alphonso's software uses your device's microphone to identify what movies and TV shows are playing around you, then takes that information to build a better advertising profile on you.

While this isn't the most invasive behavior possible, it's probably not something you'd prefer to happen on your device. Even while you're not playing lousy cash-grab mobile games, they could still be using your phone's resources to snoop on what you're watching. If you watch a lot of sports, for example, you might see more ads for team equipment.

If an app has access to your microphone, it has the ability to listen to what you're doing, so think carefully about what apps you approve this for.

Thankfully, this isn't as much of an issue on modern Android and iOS versions. On Android, the most lenient permission for the microphone permission is Allow only while using the app. Apps can't use the microphone all the time unless they're doing so for special purposes like accessibility.

And on iOS 14 and later, and Android 12 and later, you'll see an indicator icon when apps are using your mic.

2. Camera

You probably don't need an elaborate explanation on why a malicious app having access to your camera could be dangerous. While many apps need this permission for legitimate reasons, usually to take pictures inside the app or scan codes, this permission is as sensitive as your microphone. With full access to your camera, an app could theoretically take pictures anytime it wants.

And if it has internet access (which is so common now that neither mobile platform asks you to confirm it), the app could upload those photos to who-knows-where. In 2017, iOS developer Felix Krause demonstrated how an iPhone app could capture photos of someone while using the app, then share them immediately.

Thankfully, both Android and iOS now have controls to prevent this. iOS 14 and later show orange and green dots when an app accesses your microphone or camera, respectively. On Android, the highest camera permission level is Allow only while using the app, preventing apps from using the camera at other times. And starting in Android 12, you'll also see an on-screen indicator when apps use the mic and camera.

Keep an eye out for these indicators appearing when they shouldn't be. You wouldn't want someone to see pictures that apps secretly took while your phone was pointed at you in the bedroom or bathroom.

3. Location

Your general location isn't a big secret, since your IP address reveals your broad location. But that doesn't mean you want every app to access this data. If you can't think of a specific reason that an app needs your location, and it includes the permission, then it's likely for a nefarious purpose.

For instance, Google Maps needs your location so it can give you directions. Restaurant apps ask for your location so they can easily show you the closest stores. But free games that have no business with that information often ask for it, too. This is we recommend you don't install flashlight apps, which are infamous for loading up on unnecessary permissions, including your location.

By knowing what stores are near you and what type of area you live in, advertisers can build a better picture of what you might have interest in.

On Android, you're able to choose Allow all the time for the location permission. Be careful about what you allow this for, as an app can access your location dozens of times a day in some cases. You can also disable the Use precise location slider, which means apps will use Wi-Fi networks in your area, instead of your GPS location, to figure out where you are.

This is similar for iPhone. You can choose Always or While Using the App to control location access, as well as disabling Precise Location if you like.

Some apps ask for access to your contacts to make sharing and finding friends easy. For example, a messaging app like Telegram will check to see which of your friends also use it. But based on what we've discussed so far, it's not hard to guess how an app could abuse this permission. Apps can upload your contacts list to advertiser servers, or even spam your contacts with links to sign up for various apps.

Like other permissions, it's fairly easy to tell whether the app really needs your contacts. A game would only ask for this permission if wanted you to invite your friends and beg for more lives. You should be extra careful with this one; it's one issue to open up your own phone to threats, but unintentionally selling out your friends' contact info isn't cool.

5. SMS

This permission does not apply to iPhone, since only the Messages app can send texts. But it's an important consideration for Android users.

Aside from SMS replacement apps, an app might ask for permission to use your text messages so it can retrieve a login code without you having to enter it manually. These are both legitimate uses, but like everything else, they have a dark side.

A nasty app could use this permission to send a ton of texts to premium numbers and rack up a big bill for you. Or it could text your contacts a fake story about needing monetary help (in the form of untraceable gift cards), then delete those messages so you don't see them.

That's quite a bit of trust to put into an app, in exchange for saving you the five seconds it takes to enter a code manually. Only grant this permission for apps that really need to send and read texts.

Permissions Depend on Context

We're not trying to scare you into never using apps on your phone. It's not as if every app that asks for a permission is using it for nefarious purposes; app permissions are not bad in themselves. In fact, developers often explain what they use the permissions in the app description, or during the initial app setup. This can help you feel more confident about the apps you're using.

That's why it's vital to think critically about permission requests. Don't just blindly tap Yes every time you see a prompt. If you install a trusted camera app and it needs permission to use your camera, then you're probably OK. When a solitaire game immediately wants access to your contacts, location, and SMS, you should uninstall it—or at least deny those permissions.

Remember that popular doesn't mean safe, though. There are many popular Android apps that you should stay away from. Thankfully, for many types of apps, you can find an alternative. Take the time to check if there's a similar app that doesn't require as many permissions.

Make permission checks a regular part of your security routine. Every few months, take a few minutes to look over the menus mentions above. View the most sensitive permissions and ensure you aren't handing over too much info to apps that don't need it.

Manage App Permissions Wisely

We've taken a look at why permissions are important for both Android and iPhone users, discussed the most potentially dangerous ones, and saw how to take charge of permissions. All it requires is a bit of diligence and you'll have a much more private phone. Remember that all of the above scary scenarios require you to grant permission to the apps to perform their data collection, so don't approve anything that seems shady!

After checking your phone, it's smart to check for potential social media privacy dangers, too.

5 Common Social Media Privacy Issues (And How to Fix Them)

Social media and privacy are mostly incompatible, but you can reduce how much personal data you share with a few simple tips.