COMMON WEAKNESS ENUMERATIONStable

CWE-1189

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.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

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

Extended 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.

Root cause

How and when does the problem arise?

Lifecycle phase

Architecture and Design

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Bypass Protection Mechanism

Affected security scopes: Access Control

If resources being used by a trusted user are shared with an untrusted user, the untrusted user may be able to modify the functionality of the shared resource of the trusted user.
Quality Degradation

Affected security scopes: Integrity

The functionality of the shared resource may be intentionally degraded.

Defence

How is it prevented and fixed?

Architecture and Design

Separation of Privilege

Detail
When sharing resources, avoid mixing agents of varying trust levels. Untrusted agents should not share resources with trusted agents.

Verification

How is it detected?

Automated Dynamic Analysis

High
Pre-silicon / post-silicon: Test access to shared systems resources (memory ranges, control registers, etc.) from untrusted software to verify that the assets are not incorrectly exposed to untrusted agents. Note that access to shared resources can be dynamically allowed or revoked based on system flows. Security testing should cover such dynamic shared resource allocation and access control modification flows.
CWE-1189: Common Weakness Enumeration Entry CWE-1189 · DayBreach Sözlük · DayBreach