Anomalous behavior in a multi-tenant computing environment may be identified by analyzing hardware sensor value data associated with hardware events on a host machine. A privileged virtual machine instance executing on a host machine acquires hardware sensor values and causes the values to be compared to other hardware sensor value data that may be indicative of anomalous behavior; for example, various threshold values, patterns, and/or signatures of hardware counter values generated by analyzing and correlating hardware event counter data. In this manner, potential anomalous behavior on an instance may be determined without having to access customer data or workloads associated with the instance.