Researchers have discovered a weakness in Android that is likely present in other leading operating systems that can be abused and lead to information leakage. The researchers developed an application that would have to be running in the background on the affected device that hijacks the UI state. They were able to measure state changes in the UI via a shared memory side channel and determine with better than 90 percent accuracy in some cases what activity the users were undertaking, and launch a second attack that could steal sensitive inputs such as log-in credentials.
Source: https://threatpost.com/side-channel-attack-android-weakness-likely-on-other-platforms/107903/