Answer: The sound of birds chirping.
The birds singing may no longer be the sign of a good day. Instead, it could mean you’re being hacked.
Researchers at Germany’s Ruhr-Universität in Bochum discovered that they could manipulate audio files of chirping birds in order to confuse the deep neural networks behind the voice assistants like Amazon’s Alexa and Google’s Assistant. The manipulation is undetectable to human ears, but not to the microphones on these devices.
Theoretically, this technique could be used for widespread hidden commands through mediums like TV commercials or radio broadcasts, hitting thousands of devices simultaneously. The research team did not test the device’s ability to pick up the sounds when delivered through a broadcast; rather, they only played them so that the microphones could hear them clearly. There’s no telling how effective a broadcast attack would therefore be, but it definitely should not be ruled out as a possibility.