Abstract: In an embodiment, the disclosed technologies monitor electronic message traffic between a network and a recipient computer system. An embodiment includes extracting, from an electronic message received from the network, a sending domain and message data, computing a lookalike score based on the sending domain, and assigning a message type to the electronic message based on the message data. The lookalike score and the message type may be used to determine whether the electronic message is a spoofing attack such as a business email compromise (BEC) attack. In response to determining that the electronic message is malicious, an embodiment may cause the network to at least one of modify, delay, re-route, or block transmission of the electronic message to the recipient computer system.