Backdoor:Android/Hummingbad

Classification

Category :

Malware

Type :

Backdoor

Platform :

Android

Aliases :

Backdoor:Android/Hummingbad.[variant]

Summary

Backdoor:Android/Hummingbad is an app that uses deceptive measures to trick users into clicking on advertisements (a practice known as 'clickfraud'). It also installs a backdoor with root privileges on the affected device, allowing it to silently install other programs and remain persistent even after a system reboot.

Removal

Once the scan is complete, the F-Secure security product will ask if you want to uninstall the file, move it to the quarantine or keep it installed on your device.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Backdoor:Android/Hummingbad apps are mostly distributed on third-party app repositories. According to reports, the apps are also spread by drive-by downloads, when a compromised or malicious site is able to exploit a vulnerability that allows it to silently install the app on a visitor's device.

According to reports, the majority of users affected by Hummingbad malware are located in China and India, though users in other regions have also been noted.

Rooting the device

Once installed on the device, the app tries to get root access by targeting multiple vulnerabilities; if one is successfully exploited, the app gains control of the entire system and essentially functions as a backdoor, allowing a remote attacker full control of the device.

If a vulnerability-based attack is not successful, the app tries to trick the user into granting it root access by displaying a message that looks like system notification. If the user grants system-wide privileges to the app, again it essentially gives a remote attacker control of the device.

Ads and app downloads

Whether or not root access is gained, the app will silently download and install other components onto the device. These components have various functions, usually either displaying advertisements or downloading still more apps.

The ad-displaying component displays advertising content sourced from third-party advertising networks on the device. It also interferes with attempts by the user to dismiss any ads shown (for example, by clicking back or returning to the home screen) in order to force them to click on the ad. This forced-clicking is used to generate revenue from the ad networks, a practice known as 'clickfraud'.

Another downloaded component is able to mimic the behavior of a user in order to download and install apps onto the affected device.