CWE - CWE-1328: Security Version Number Mutable to Older Versions (4.14)

Weakness ID: 1328

Vulnerability Mapping: ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

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Description

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

Extended Description

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.

Relationships

This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	757	Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

Relevant to the view "Hardware Design" (CWE-1194)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1196	Security Flow Issues

Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Phase	Note
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

This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Operating Systems

Class: Not OS-Specific (Undetermined Prevalence)

Architectures

Class: Not Architecture-Specific (Undetermined Prevalence)

Technologies

Security Hardware (Undetermined Prevalence)

Class: Not Technology-Specific (Undetermined Prevalence)

Common Consequences

This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Scope	Impact	Likelihood
Confidentiality Integrity Authentication Authorization	Technical Impact: Other Impact includes roll-back or downgrade to a vulnerable version of the firmware or DoS (prevent upgrades).	High

Demonstrative Examples

Example 1

A new version of firmware is signed with a security version number higher than the previous version. During the firmware update process the SoC checks for the security version number and upgrades the SoC firmware with the latest version. This security version number is stored in persistent memory upon successful upgrade for use across power-on resets.

In general, if the security version number is mutable, the implementation is vulnerable. A mutable security version number allows an adversary to change the security version to a lower value to allow roll-back or to a higher value to prevent future upgrades.

The security version number should be stored in immutable hardware such as fuses, and the writes to these fuses should be highly access-controlled with appropriate authentication and authorization protections.

Potential Mitigations

Phase: 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.

Phase: 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

Memberships

This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

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

CAPEC-ID	Attack Pattern Name
CAPEC-176	Configuration/Environment Manipulation

Content History

Submissions
Submission Date	Submitter	Organization
2020-04-25 (CWE 4.3, 2020-12-10)	Arun Kanuparthi, Hareesh Khattri, Parbati Kumar Manna	Intel Corporation
2020-04-25 (CWE 4.3, 2020-12-10)
Modifications
Modification Date	Modifier	Organization
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Related_Attack_Patterns
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Demonstrative_Examples
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Applicable_Platforms
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Applicable_Platforms
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes


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Common Weakness Enumeration

CWE-1328: Security Version Number Mutable to Older Versions

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