The 'behavior' based antivirus works in the same way. It tries to identify the 'behavior' of a file. E.g. an mp3 file trying to modify a system file or something like that which is unacceptable...
Enter behavior-based antivirus. Security experts have realized that while viruses all look different, the symptoms of their behavior are almost always the same.
Why Antivirus Needs to Watch Behavior, Not Just Files. You can think of behavior based detection as the antivirus version of watching someones actions instead of checking their ID.

Furthermore, visual representations like the one above help us fully grasp the concept of Behactor Based Anti Virus.
Behavior-based security or antivirus is a game-changing solution to have in your cybersecurity arsenal. An example of this is the SentinelOne endpoint security platform.
Behavior-based antivirus software protects against new and unknown malware. It looks for threats based on intentions, which can catch viruses that other methods might miss.

Behavior-based antivirus software, meanwhile, focuses on identifying new and unknown malware by analyzing their intentions. The Major Benefits of Antivirus Software.
How Behaviour-Based Detection Can Be Helpful. These antivirus solutions are becoming more popular due to their adaptability and ability to detect more sophisticated threats.

Email Protection, Web Protection, Firewall, Definition (Sandbox) Antivirus, User Awareness. Training. Attack Surface Reduction, Patch Management, Behavior-based AV