Identification device, identification method, and identification program

A command server identification device adds a tag to data received by malware upon execution of the malware, the tag capable of uniquely identifying identification information for a transmission source of the data, and tracks propagation of the data added with the tag. The command server identification device acquires a tag of data referenced by a branch instruction executed by the malware, among the tracked data. The command server identification device analyzes information on an instruction of a branch destination not executed by the malware after the branch instruction. Then, the command server identification device identifies identification information of a command server for issuing a command to the malware from the identification information of the transmission source corresponding to the acquired tag, based on the result of analysis.