CWE-1328 Detail

Security-version number in hardware is mutable, resulting in the ability to downgrade (roll-back) the boot firmware to vulnerable code versions.

A System-on-Chip (SoC) implements secure boot or verified boot. It might support a security version number, which prevents downgrading the current firmware to a vulnerable version. Once downgraded to a previous version, an adversary can launch exploits on the SoC and thus compromise the security of the SoC. These downgrade attacks are also referred to as roll-back attacks.

The security version number must be stored securely and persistently across power-on resets. A common weakness is that the security version number is modifiable by an adversary, allowing roll-back or downgrade attacks or, under certain circumstances, preventing upgrades (i.e. Denial-of-Service on upgrades). In both cases, the SoC is in a vulnerable state.

Modes Of Introduction

Architecture and Design
Implementation : Such issues could be introduced during hardware architecture and design, and can be identified later during testing or system configuration phases.

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Operating Systems

Class: Not OS-Specific (Undetermined)

Architectures

Class: Not Architecture-Specific (Undetermined)

Technologies

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

Common Consequences

Potential Mitigations

Phases : Architecture and Design
When architecting the system, security version data should be designated for storage in registers that are either read-only or have access controls that prevent modification by an untrusted agent.
Phases : Implementation
During implementation and test, security version data should be demonstrated to be read-only and access controls should be validated.

Detection Methods

Automated Dynamic Analysis

Mutability of stored security version numbers and programming with older firmware images should be part of automated testing.
Effectiveness : High

Architecture or Design Review

Anti-roll-back features should be reviewed as part of Architecture or Design review.
Effectiveness : High

Vulnerability Mapping Notes

Justification : 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.
Comment : 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

Submission

Modifications