1. A method for non-intrusively detecting counterfeit components in a target computer system, the method comprising: collecting target electromagnetic interference (EMI) signals generated by the target computer system using one or more antennas positioned in close proximity to the target computer system; generating a target EMI fingerprint for the target computer system from the target EMI signals; and comparing the target EMI fingerprint against a reference EMI fingerprint to determine whether the target computer system contains a counterfeit component.