Systems and methods for enabling trusted software to monitor and control USB traffic associated with a security extension of a host controller and devices in a USB topology is disclosed. A host controller proxy receives USB-related data from a host controller driver, determines whether the data is of a security interest, and if so, sends the data to a driver for a security extension executing in the trusted execution environment. Likewise, after software executing in the trusted execution environment evaluates and appropriately addresses data sent by the HCD proxy or data retrieved from a hardware security extension, the HCD proxy receives data from the trusted execution environment for further dissemination.