One variation of a system for emulating a known attack on a computer network includes a computer system configured to: generate a set of data packets by recombining packet fragments transmitted between machines during a prior malicious attack on a second network; define transmission triggers for transmission of the set of data packets between pairs of agents connected to a target network based on timestamps of packet fragments; generate an executable file including the set of data packets and the transmission triggers; initiate transmission of the set of data packets between the pairs assets according to the set of transmission triggers to emulate the malicious attack on the target network; and, in response to absence of a security event related to the emulation in a log of a security technology deployed on the target network, generate a prompt to reconfigure the security technology to respond to the malicious attack.