A network traffic correlation engine monitors inbound and/or outbound connection information received from on each host computer system on a network. Each host device on the network store data logs corresponding to information corresponding to communications sent by the device and received by the device. The network traffic correlation engine correlates connections between different hosts throughout the network. If the network traffic correlation engine identified unmatched outbound and inbound connections, the network traffic correlation engine generates an alert to initiate further investigation and may also provide a mapping of the communications showing a possible start device for the connection and/or a type of access that the connections may now be providing.