Using a USB host controller security extension for controlling changes in and auditing USB topology

摘要

Protecting computer systems from attacks that attempt to change USB topology and for ensuring that the system's information regarding USB topology is accurate is disclosed. A software model is defined that, together with secure USB hardware, provides an ability to define policies using which USB traffic can be properly monitored and controlled. The implemented policy provides control over USB commands through a combination of software evaluation and hardware programming. Legitimate commands are evaluated and “allowed” to be sent to a USB device by a host controller. Illegitimate commands are evaluated and blocked. Additionally, the USB topology is audited to verify that the system's topology map matches the actual USB topology.