CWE - CWE-1271: Uninitialized Value on Reset for Registers Holding Security Settings (4.15)

Weakness ID: 1271

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-critical logic is not set to a known value on reset.

Extended Description

When the device is first brought out of reset, the state of registers will be indeterminate if they have not been initialized by the logic. Before the registers are initialized, there will be a window during which the device is in an insecure state and may be vulnerable to attack.

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
Access Control Authentication Authorization	Technical Impact: Varies by Context

Potential Mitigations

Phase: Implementation

Design checks should be performed to identify any uninitialized flip-flops used for security-critical functions.

Phase: Architecture and Design

All registers holding security-critical information should be set to a specific value on reset.

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.	909	Missing Initialization of Resource

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.	1206	Power, Clock, Thermal, and Reset Concerns
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.	1304	Improperly Preserved Integrity of Hardware Configuration State During a Power Save/Restore Operation

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
Implementation

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

Class: Not Technology-Specific (Undetermined Prevalence)

Demonstrative Examples

Example 1

Shown below is a positive clock edge triggered flip-flop used to implement a lock bit for test and debug interface. When the circuit is first brought out of reset, the state of the flip-flop will be unknown until the enable input and D-input signals update the flip-flop state. In this example, an attacker can reset the device until the test and debug interface is unlocked and access the test interface until the lock signal is driven to a known state by the logic.

(bad code)

Example Language: Verilog

always @(posedge clk) begin

if (en) lock_jtag <= d;

end

The flip-flop can be set to a known value (0 or 1) on reset, but requires that the logic explicitly update the output of the flip-flop if the reset signal is active.

(good code)

Example Language: Verilog

always @(posedge clk) begin

if (~reset) lock_jtag <= 0;
else if (en) lock_jtag <= d;

end

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

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.	1416	Comprehensive Categorization: Resource Lifecycle Management

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.

Notes

Maintenance

This entry is still under development and will continue to see updates and content improvements.

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-74	Manipulating State

Content History

Submissions
Submission Date	Submitter	Organization
2020-05-15 (CWE 4.1, 2020-02-24)	Nicole Fern	Tortuga Logic
2020-05-15 (CWE 4.1, 2020-02-24)
Modifications
Modification Date	Modifier	Organization
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Common_Consequences, Demonstrative_Examples, Description, Modes_of_Introduction, Name, Potential_Mitigations, Related_Attack_Patterns, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Name, Type
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Weakness_Ordinalities
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Demonstrative_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Relationships
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
Previous Entry Names
Change Date	Previous Entry Name
2020-08-20	Missing Known Value on Reset for Registers Holding Security Settings

2021-03-15	Unitialized Value on Reset for Registers Holding Security Settings


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Common Weakness Enumeration

CWE-1271: Uninitialized Value on Reset for Registers Holding Security Settings

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