How to check if an APK file is virus free

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The list is presented under the last button "Download and install" of the Google Play Store. For an application installed via an .apk file, the list appears once the file is opened, before the “Install” button. On the Play Store, some developers explain the permissions needs in the description. The permissions to watch first are below.

Network connections. Many apps ask for this permission just to display advertising. If the app is not linked to a web service (like Facebook ) and is ad-free, this permission is not meant to be useful.
Personal data. Access to your accounts can be requested by applications providing access to an online service, with a view to adding entries to your address book ( Facebook , Twitter , LinkedIn, etc.). Otherwise, it is better to refuse access.
Phone state. For applications such as games or music or video players, this allows you to stop the game session or playback when a call is received, and resume afterwards. Outside of these uses, it is recommended to refuse applications requesting it.
Confidential system logs. This is the most sensitive data on the device. Unless you know exactly what this permission is technically for the application, absolutely refuse all those asking for it.
Location. Location-based apps may need to know your location, as may some in-app ad services. Be careful if it is a lightly downloaded application (less than 10,000 downloads).
Messages. Outside of messaging applications, few software can legitimately request access to your messages. Only install applications that directly process your mail if this access is requested.

Beware of apps that can make calls for you or send text messages. If these are not dedicated applications (SMS client, telephony tool, etc.), there is a chance that the use of these permissions is fraudulent. So avoid installing the (rare) applications requiring these permissions.

Finally, it is recommended not to allow the installation of third-party applications, in installation files (.apk), or by third-party stores. Unless there is a special need (to be reserved for experienced mobile users), forbid this option. In Android 1.x and 2.x, go to the “Applications” menu in System Settings and uncheck the “Unknown sources” box. On Android 3.x and 4.x, the box is located in the “Device management” section of the “Security” menu in Settings.

answered Dec 6, 2020 by backtothefuture (551k points)

Download apps safely from outside the Play Store?

We no longer count the number of applications, updates or games blocked on the French version of the Play Store. Not to mention the applications not compatible with your device. This can be particularly frustrating. To get around this limitation, more and more internet users decide to retrieve the app as an APK and then install it on their smartphone.

Many alternative platforms offer a whole bunch of applications or games (more or less legal) for free download. Unlike the versions available on the Google store, these installation files are not those officially offered by the publishers. In addition, they are not subject to Google security filters .

So it's not uncommon to come across stolen APK files masquerading as popular apps. Once installed on a smartphone, the malware will attempt to take control of your Android device and then steal or encrypt your confidential data. Obviously each time the hackers demand ransoms of several hundred or thousands of euros to unlock the devices. Distrust therefore.

How to determine if an APK file is not infected

So how can you be sure not to install a virus and infect your smartphone? To find malicious APK apps , start by scanning them with your Android antivirus. If the file you want to install is potentially dangerous, you will receive an alert message. Obviously this solution is not always infallible.

Total Virus

To ensure the reliability of an APK file, you can also use online services like Virus Total. This tool (bought by Google) accessible from a website facilitates the detection of viruses, adware and malware hidden in an APK file. Unlike a conventional antivirus, Virus Total uses several virus scanning engines and the malware signatures are updated in real time. As a result, it offers one of the highest threat detection rates on the market.

Open your web browser
Type the following URL address https://www.virustotal.com/fr/
Click on File then send the APK file to be analyzed. Please note that the size of your file cannot exceed 64 MB.
Wait a few seconds for VirusTotal to display the scan report.

APK Analyzer

Before installing an APK file, you should also check the requested permissions. If a game asks you to access your calendar, this should alert you. Hackers have become accustomed to modifying applications by asking them for more permissions than they need. This is why you should be wary of applications requiring a whole bunch of permissions.

To find applications that are a little too curious, get help with the APK Analyzer tool.

Open the Google Play Store and type APK Analyzer in the search engine of the official Google store
Install the verification tool
Launch APK Analyzer
The security tool will analyze all APK files downloaded on your smartphone including those that you have not installed yourself
Select the APK file to be analyzed from the list
In the Basic Information field, note the number of permissions requested as well as the weight of the application.
Then compare these figures with those provided by the Google Play Store

If you spot a difference, it's best not to install this suspicious APK file. When in doubt, it is best to remain cautious. This is all the more true if the installation file comes from a questionable shop as we sometimes find on the net.

Some tips before downloading an APK

Before installing an application from an unknown source, it comes from respecting certain rules. Always favor stores with a storefront as the application market of Amazon. Also remember to check the MD5 fingerprint of the signing certificate to verify the integrity of your file.

Activate Google Play Protect

Google Play Protect integrated into the Play Store analyzes all the applications installed on your smartphone including those from alternative stores. Based on advanced machine learning technology (artificial intelligence), this service identifies malware and can even delete applications considered dangerous if necessary. Google Play Protect is enabled normally by default.

Launch the Play Store app
Press the Menu button (3 horizontal bars)
Click on Play Protect
Activate the option Search for security threats

The Google Play Protect service automatically scans the apps you have downloaded at regular intervals. If malware or a potentially dangerous app is found, you will receive a notification warning you of the risk. Then click on the uninstall button in the notification to remove the problem app.