Embodiments disclosed herein generally relate to a system and method for detecting fraudulent computer activity. A computing system generates a plurality of synthetic identities. Each of the plurality of synthetic identities mimics information associated with a verified identity. The computing system receives, from a user, an input attempt. The input attempt includes a synthetic identity of the plurality of synthetic identities. The computing system compares input information in the input attempt to the plurality of synthetic identities. The computing system determines that the input information in the input attempt includes information from the plurality of synthetic identities, if it does, the computing system rejects the input attempt.