CWE - CWE-325: Missing Cryptographic Step (4.17)

Weakness ID: 325

Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Base 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.

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Description

The product does not implement a required step in a cryptographic algorithm, resulting in weaker encryption than advertised by the algorithm.

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.

Impact	Details
Bypass Protection Mechanism	Scope: Access Control
Read Application Data; Modify Application Data	Scope: Confidentiality, Integrity
Hide Activities	Scope: Accountability, Non-Repudiation

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" (View-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.	573	Improper Following of Specification by Caller
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.	358	Improperly Implemented Security Check for Standard

Relevant to the view "Software Development" (View-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	310	Cryptographic Issues

Relevant to the view "Architectural Concepts" (View-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1013	Encrypt Data

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

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1205	Security Primitives and Cryptography 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
Implementation	Developers sometimes omit "expensive" (resource-intensive) steps in order to improve performance, especially in devices with limited memory or slower CPUs. This step may be taken under a mistaken impression that the step is unnecessary for the cryptographic algorithm.
Requirements	This issue may happen when the requirements for the cryptographic algorithm are not clearly stated.

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)
Technologies	Class: Not Technology-Specific (Undetermined Prevalence)

Demonstrative Examples

Example 1

The example code is taken from the HMAC engine inside the buggy OpenPiton SoC of HACK@DAC'21 [REF-1358]. HAMC is a message authentication code (MAC) that uses both a hash and a secret crypto key. The HMAC engine in HACK@DAC SoC uses the SHA-256 module for the calculation of the HMAC for 512 bits messages.

(bad code)

Example Language: Verilog

logic [511:0] bigData;
...

hmac hmac(

.clk_i(clk_i),
.rst_ni(rst_ni && ~rst_4),
.init_i(startHash && ~startHash_r),
.key_i(key),
.ikey_hash_i(ikey_hash),
.okey_hash_i(okey_hash),
.key_hash_bypass_i(key_hash_bypass),
.message_i(bigData),
.hash_o(hash),
.ready_o(ready),
.hash_valid_o(hashValid)

However, this HMAC engine cannot handle messages that are longer than 512 bits. Moreover, a complete HMAC will contain an iterate hash function that breaks up a message into blocks of a fixed size and iterates over them with a compression function (e.g., SHA-256). Therefore, the implementation of the HMAC in OpenPiton SoC is incomplete. Such HMAC engines will not be used in real-world applications as the messages will usually be longer than 512 bits. For instance, OpenTitan offers a comprehensive HMAC implementation that utilizes a FIFO for temporarily storing the truncated message, as detailed in [REF-1359].

To mitigate this, implement the iterative function to break up a message into blocks of a fixed size.

Selected Observed Examples

Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.

Reference	Description
CVE-2001-1585	Missing challenge-response step allows authentication bypass using public key.

Functional Areas

Cryptography

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.	719	OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	720	OWASP Top Ten 2007 Category A9 - Insecure Communications
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	934	OWASP Top Ten 2013 Category A6 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	958	SFP Secondary Cluster: Broken Cryptography
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1029	OWASP Top Ten 2017 Category A3 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1346	OWASP Top Ten 2021 Category A02:2021 - Cryptographic Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1366	ICS Communications: Frail Security in Protocols
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1402	Comprehensive Categorization: Encryption

Vulnerability Mapping Notes

Usage	ALLOWED (this CWE ID may 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

Relationship

Overlaps incomplete/missing security check.

Relationship

Can be resultant.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Missing Required Cryptographic Step
OWASP Top Ten 2007	A8	CWE More Specific	Insecure Cryptographic Storage
OWASP Top Ten 2007	A9	CWE More Specific	Insecure Communications

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-68	Subvert Code-signing Facilities

References

[REF-1358]	"hmac_wrapper.sv". 2021. <https://github.com/HACK-EVENT/hackatdac21/blob/main/piton/design/chip/tile/ariane/src/hmac/hmac_wrapper.sv#L41>. (URL validated: 2023-07-15)
[REF-1359]	"HMAC HWIP Technical Specification". 2023. <https://opentitan.org/book/hw/ip/hmac/>. (URL validated: 2023-10-05)

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2023-06-21	Chen Chen, Rahul Kande, Jeyavijayan Rajendran	Texas A&M University
2023-06-21	suggested demonstrative example
2023-06-21	Shaza Zeitouni, Mohamadreza Rostami, Ahmad-Reza Sadeghi	Technical University of Darmstadt
2023-06-21	suggested demonstrative example
Modifications
Modification Date	Modifier	Organization
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples, References
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Common_Consequences, Description, Modes_of_Introduction, Name
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Description, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Description, Functional_Areas, Modes_of_Introduction, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
Previous Entry Names
Change Date	Previous Entry Name
2020-08-20	Missing Required Cryptographic Step


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Common Weakness Enumeration

CWE-325: Missing Cryptographic Step

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