Android malware flaw a risk to almost 50 per cent of devices

Millions of Android devices have been found vulnerable to cyber attack following a security flaw allowing malware to replace legitimate apps, hacker Zhi Xu has found.

Almost half of Android phones may be affected, with the flaw allowing dangerous malicious apps to be downloaded without the user's knowledge, collecting personal data from the infected device.

Xu, a senior staff engineer at Palo Alto Networks, says: "The malicious application can gain full access to a compromised device, including usernames, passwords, and sensitive data."

"This hijacking technique can be used to bypass the user view and distribute malware with arbitrary permissions. It can substitute one application with another, for instance if a user tries to install a legitimate version of "Angry Birds" and ends up with a Flashlight app that's running malware."

According to the report, 49.5 per cent of Android users are still vulnerable to the threat despite patches released by Google and manufacturers such as Samsung and Amazon attempting to tackle the problem.

Applications affected only include those installed via a third-party app store, with the flaw allowing the APK file to be modified by the malware during the installation process.

The flaw was actually first found in January 2014, but the number of devices left vulnerable has dropped from 89.4 per cent to just below 50 per cent (as of march 2015) in the interim.

Users have been advised to update their phones to Android 4.1 or above to avoid being affected, though the report warns those running on Android 4.3 that they may also be open to attack.