EDR, or Endpoint Detection and Response, is security software installed on the devices themselves, such as laptops, desktops, and servers. It watches continuously for behavior that suggests an attack, rather than waiting for a known virus signature to match.
When EDR finds something suspicious, it can act. It can block the activity, isolate the machine from the rest of the network, and give an IT team the details they need to respond. This is a large step beyond traditional antivirus, which mostly checks for known bad files and does not see new or sneaky attacks.
