The present disclosure is directed to systems and methods of detecting a side-channel attack using hardware counter anomaly detection circuitry to select a subset of HPCs demonstrating anomalous behavior in response to a side-channel attack. The hardware counter anomaly detection circuitry includes data collection circuitry to collect data from a plurality of HPCs, time/frequency domain transform circuitry to transform the collected data to the frequency domain, one-class support vector anomaly detection circuitry to detect anomalous or aberrant behavior by the HPCs. The hardware counter anomaly detection circuitry selects the HPCs having reliable and consistent anomalous activity or behavior in response to a side-channel attack and groups those HPCs into a side-channel attack detection HPC sub-set that may be communicated to one or more external devices.