Digital fingerprint generation logic executed by a client device includes quirk-exposing logic configured to expose behavioral differences between various system configurations of client devices. The digital fingerprint generation logic queries a remote client device for system configuration, and generates a digital fingerprint of the client device that includes a system configuration characteristic reported by the client device in response to the query. Results of execution of the quirk-exposing logic are compared to expected results that are specific to the reported system configuration. If the results of execution do not match the expected results, the digital fingerprint is determined to have been spoofed.