COMMON WEAKNESS ENUMERATIONStable

CWE-1244

Internal Asset Exposed to Unsafe Debug Access Level or State

The product uses physical debug or test interfaces with support for multiple access levels, but it assigns the wrong debug access level to an internal asset, providing unintended access to the asset from untrusted debug agents.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The product uses physical debug or test interfaces with support for multiple access levels, but it assigns the wrong debug access level to an internal asset, providing unintended access to the asset from untrusted debug agents.

Extended description

Debug authorization can have multiple levels of access, defined such that different system internal assets are accessible based on the current authorized debug level. Other than debugger authentication (e.g., using passwords or challenges), the authorization can also be based on the system state or boot stage. For example, full system debug access might only be allowed early in boot after a system reset to ensure that previous session data is not accessible to the authenticated debugger.

Root cause

How and when does the problem arise?

Lifecycle phase

Architecture and Design

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Read Memory

Affected security scopes: Confidentiality

If a protection mechanism does not ensure that internal assets have the correct debug access level during each boot stage or change in system state, an attacker could obtain sensitive information from the internal asset using a debugger.
Modify Memory

Affected security scopes: Integrity

Gain Privileges or Assume IdentityBypass Protection Mechanism

Affected security scopes: Authorization, Access Control

Defence

How is it prevented and fixed?

Architecture and Design · Implementation

Defence to apply across several lifecycle phases

Detail
For security-sensitive assets accessible over debug/test interfaces, only allow trusted agents.

Effectiveness: High

Architecture and Design

Architecture and design approach

Detail
Apply blinding [REF-1219] or masking techniques in strategic areas.

Effectiveness: Limited

Implementation

Implementation-phase defence

Detail
Add shielding or tamper-resistant protections to the device, which increases the difficulty and cost for accessing debug/test interfaces.

Effectiveness: Limited

Verification

How is it detected?

Manual Analysis

Moderate
Check 2 devices for their passcode to authenticate access to JTAG/debugging ports. If the passcodes are missing or the same, update the design to fix and retest. Check communications over JTAG/debugging ports for encryption. If the communications are not encrypted, fix the design and retest.