Improper Isolation of Shared Resources on System-on-a-Chip (SoC)

The System-On-a-Chip (SoC) does not properly isolate shared resources between trusted and untrusted agents.


Description

A System-On-a-Chip (SoC) has a lot of functionality, but it may have a limited number of pins or pads. A pin can only perform one function at a time. However, it can be configured to perform multiple different functions. This technique is called pin multiplexing. Similarly, several resources on the chip may be shared to multiplex and support different features or functions. When such resources are shared between trusted and untrusted agents, untrusted agents may be able to access the assets intended to be accessed only by the trusted agents.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

Consider the following SoC design. The Hardware Root of Trust (HRoT) local SRAM is memory mapped in the core{0-N} address space. The HRoT allows or disallows access to private memory ranges, thus allowing the sram to function as a mailbox for communication between untrusted and trusted HRoT partitions.

We assume that the threat is from malicious software in the untrusted domain. We assume this software has access to the core{0-N} memory map and can be running at any privilege level on the untrusted cores. The capability of this threat in this example is communication to and from the mailbox region of SRAM modulated by the hrot_iface. To address this threat, information must not enter or exit the shared region of SRAM through hrot_iface when in secure or privileged mode.

See Also

Privilege Separation and Access Control Issues

Weaknesses in this category are related to features and mechanisms providing hardware-based isolation and access control (e.g., identity, policy, locking control) of s...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses in the 2021 CWE Most Important Hardware Weaknesses List

CWE entries in this view are listed in the 2021 CWE Most Important Hardware Weaknesses List, as determined by the Hardware CWE Special Interest Group (HW CWE SIG).

Weaknesses without Software Fault Patterns

CWE identifiers in this view are weaknesses that do not have associated Software Fault Patterns (SFPs), as covered by the CWE-888 view. As such, they represent gaps in...


Common Weakness Enumeration content on this website is copyright of The MITRE Corporation unless otherwise specified. Use of the Common Weakness Enumeration and the associated references on this website are subject to the Terms of Use as specified by The MITRE Corporation.