Abstract: A security fastener assembly is provided with a cap having a standard tool bearing surface and an attachment portion formed opposite the tool bearing surface. A fastener body has a mating attachment portion formed at a first end along which the cap is secured and a keyed security feature formed adjacent the mating attachment portion. A second end of the fastener body has a threaded fastener portion for securing the fastener assembly to a vehicle. The threaded portion of the fastener body is installed with rotation in a first direction. Engaging the tool bearing surface of the cap and rotating in a second direction opposite the first direction does not rotate the threaded portion of the fastener body. The fastener body is removable with the keyed security feature.