I’m not clear on this particular one, but I believe there can be both. Onboard sensors can initiate flight termination as well as a ground-based range safety officer.
Edit: Yeah. Looks like there have been autonomous methods since about 1998.
An autonomous flight termination system (AFTS) or autonomous flight safety system (AFSS) is a system in which the rocket’s flight computer can command flight termination without depending on ground personnel.