1. A malicious-module identification device for identifying and deactivating a malicious module operating on an information processing device connected to the malicious-module identification device via a network, the malicious-module identification device comprising: a reception unit configured to receive results of tampering detection from a plurality of modules performing tampering detection; a determination unit configured to assume that a module among the plurality of modules is a normal module, to determine, based on the assumption, whether a contradiction occurs in the received results of tampering detection, and to identify the module assumed to be a normal module as a malicious module when determining that a contradiction occurs; and a deactivation unit configured to output an instruction to deactivate the module identified as the malicious module.