Detecting risky network communications based on evaluation using normal and abnormal behavior profiles

A technique detects riskiness of a communication in a network based on behavior profiling. The technique involves generating a network history baseline (e.g., normal and abnormal behavior profiles) from prior network communications occurring in the network. The technique further involves, for a new network communication, assigning the new network communication a risk score based on a comparison of the new network communication to the network history baseline. The risk score is a numerical measure of behavioral normalcy relative to the prior network communications occurring in the network. The technique further involves providing an output signal having a first value when the risk score is above a predefined risk threshold to indicate that the communication is risky, and a second value which is different than the first value when the risk score is below the predefined risk threshold to indicate that the communication is not risky.