Improper Setting of Bus Controlling Capability in Fabric End-point

Opis

The bus controller enables bits in the fabric end-point to allow responder devices to control transactions on the fabric.

To support reusability, certain fabric interfaces and end points provide a configurable register bit that allows IP blocks connected to the controller to access other peripherals connected to the fabric. This allows the end point to be used with devices that function as a controller or responder. If this bit is set by default in hardware, or if firmware incorrectly sets it later, a device intended to be a responder on a fabric is now capable of controlling transactions to other devices and might compromise system security.

Skutki

• Access Control

  Modify Memory; Read Memory; Bypass Protection Mechanism

Zapobieganie

• Architecture and Design

  For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.

• Implementation

  For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.

• System Configuration

  For responder devices, the register bit in the fabric end-point that enables the bus controlling capability must be set to 0 by default. This bit should not be set during secure-boot flows. Also, writes to this register must be access-protected to prevent malicious modifications to obtain bus-controlling capability.

Słabość nadrzędna

• CWE-284 Improper Access Control

Kiedy powstaje

• Architecture and Design
• Implementation
• System Configuration

Dotyczy

Not Language-Specific, Not OS-Specific, Not Architecture-Specific, Not Technology-Specific

Źródła

1. Bypassing IOMMU Protection against I/O Attacks — Benoit Morgan, Eric Alata, Vincent Nicomette, Mohamed Kaaniche, 2016
2. Exploitation from malicious PCI Express peripherals — Colin L. Rothwell, 2019