A computer implemented method to identify an attacked computing device in a system of network-connected computing devices providing a plurality of computing services, the method including receiving a first data structure including data modeling relationships between vulnerabilities of computing services in a first proper subset of the plurality of computing services and exploitation of such vulnerabilities to identify one or more series of exploits involved in a network attack; receiving a second data structure including data modeling the computing devices in the system including the network connections of each computing device; and comparing the first and second data structures to identify the attacked computing device as an intermediate device in communications between at least two computer services in any of the one or more series of exploits.