Running an application inside an emulator/simulator allows an attacker to hook or trace program execution. For applications running inside an emulator, it is easy to inspect the system's state, reset it to a saved image, or monitor how the app operates. Keep in mind that not every emulator/simulator usage means an ongoing potential threat for the application.
Below are code snippets demonstrating emulator detection across various platforms:
Recommended action: Notify users that their device is insecure and log the event on your BE. Some of the applications (mostly banking) are often even killed upon the detection of this threat.