Is ADB on or off?

Turn it off. Adb is a general command line tool, which allows communication with connected Android devices, facilitates device operation, such as installing and debugging applications, and provides access to Unix shell (which can be used to run various commands on simulators or connected devices). Criminals can implant online banking Trojans into Android phones, play advertising videos to Android set-top boxes, use mobile phones to dig for money, and steal text messages and address books. Therefore, in order to protect personal information and security, they should be closed.