The product uses a fabric bridge for transactions between two Intellectual Property (IP) blocks, but the bridge does not properly perform the expected privilege, identity, or other access control checks between those IP blocks.

In hardware designs, different IP blocks are connected through interconnect-bus fabrics (e.g. AHB and OCP). Within a System on Chip (SoC), the IP block subsystems could be using different bus protocols. In such a case, the IP blocks are then linked to the central bus (and to other IP blocks) through a fabric bridge. Bridges are used as bus-interconnect-routing modules that link different protocols or separate, different segments of the overall SoC interconnect.

For overall system security, it is important that the access-control privileges associated with any fabric transaction are consistently maintained and applied, even when they are routed or translated by a fabric bridge. A bridge that is connected to a fabric without security features forwards transactions to the slave without checking the privilege level of the master and results in a weakness in SoC access-control security. The same weakness occurs if a bridge does not check the hardware identity of the transaction received from the slave interface of the bridge.

Modes Of Introduction

Architecture and Design
Implementation

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Operating Systems

Class: Not OS-Specific (Undetermined)

Architectures

Class: Not Architecture-Specific (Undetermined)

Technologies

Name: Processor Hardware (Undetermined)
Class: Not Technology-Specific (Undetermined)

Common Consequences

Observed Examples

Potential Mitigations

Phases : Architecture and Design
Ensure that the design includes provisions for access-control checks in the bridge for both upstream and downstream transactions.
Phases : Implementation
Implement access-control checks in the bridge for both upstream and downstream transactions.

Detection Methods

Simulation / Emulation

RTL simulation to ensure that bridge-access controls are implemented properly.
Effectiveness : High

Formal Verification

Formal verification of bridge RTL to ensure that access control cannot be bypassed.
Effectiveness : High

Vulnerability Mapping Notes

Rationale : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Related Attack Patterns

References

REF-1138

CVE-2019-6260: Gaining control of BMC from the host processor
Stewart Smith.
https://www.flamingspork.com/blog/2019/01/23/cve-2019-6260:-gaining-control-of-bmc-from-the-host-processor/

REF-1381

aes0_wrapper.sv lines 72 - 78
https://github.com/HACK-EVENT/hackatdac21/blob/b9ecdf6068445d76d6bee692d163fededf7a9d9b/piton/design/chip/tile/ariane/src/aes0/aes0_wrapper.sv#L72-L78

REF-1382

clint.sv line 71
https://github.com/HACK-EVENT/hackatdac21/blob/b9ecdf6068445d76d6bee692d163fededf7a9d9b/piton/design/chip/tile/ariane/src/clint/clint.sv#L71C2-L71C36

REF-1383

Fix for clint.sv line 78
https://github.com/HACK-EVENT/hackatdac21/blob/45a004368b5a31857008834d9780536f0764f055/piton/design/chip/tile/ariane/src/clint/clint.sv#L78

Submission

Modifications