CWE

Common Weakness Enumeration

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ID

CWE-654: Reliance on a Single Factor in a Security Decision

Weakness ID: 654
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
A protection mechanism relies exclusively, or to a large extent, on the evaluation of a single condition or the integrity of a single object or entity in order to make a decision about granting access to restricted resources or functionality.
+ Alternate Terms
Separation of Privilege:
Some people and publications use the term "Separation of Privilege" to describe this weakness, but this term has dual meanings in current usage. While this entry is closely associated with the original definition of "Separation of Privilege" by Saltzer and Schroeder, others use the same term to describe poor compartmentalization (CWE-653). Because there are multiple interpretations, use of the "Separation of Privilege" term is discouraged.
+ Common Consequences
Section HelpThis 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.
ScopeImpactLikelihood
Access Control

Technical Impact: Gain Privileges or Assume Identity

If the single factor is compromised (e.g. by theft or spoofing), then the integrity of the entire security mechanism can be violated with respect to the user that is identified by that factor.
Non-Repudiation

Technical Impact: Hide Activities

It can become difficult or impossible for the product to be able to distinguish between legitimate activities by the entity who provided the factor, versus illegitimate activities by an attacker.
+ Potential Mitigations

Phase: Architecture and Design

Use multiple simultaneous checks before granting access to critical operations or granting critical privileges. A weaker but helpful mitigation is to use several successive checks (multiple layers of security).

Phase: Architecture and Design

Use redundant access rules on different choke points (e.g., firewalls).
+ Relationships
Section HelpThis 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)
NatureTypeIDName
ChildOfPillarPillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.693Protection Mechanism Failure
ChildOfClassClass - 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.657Violation of Secure Design Principles
ParentOfBaseBase - 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.308Use of Single-factor Authentication
ParentOfBaseBase - 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.309Use of Password System for Primary Authentication
PeerOfBaseBase - 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.1293Missing Source Correlation of Multiple Independent Data
Section HelpThis 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 "Software Development" (CWE-699)
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1006Bad Coding Practices
+ Modes Of Introduction
Section HelpThe 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.
PhaseNote
Architecture and Design
Implementation
Operation
+ Applicable Platforms
Section HelpThis 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)

+ Demonstrative Examples

Example 1

Password-only authentication is perhaps the most well-known example of use of a single factor. Anybody who knows a user's password can impersonate that user.


Example 2

When authenticating, use multiple factors, such as "something you know" (such as a password) and "something you have" (such as a hardware-based one-time password generator, or a biometric device).


+ Observed Examples
ReferenceDescription
Chat application skips validation when Central Authentication Service (CAS) is enabled, effectively removing the second factor from two-factor authentication
+ Weakness Ordinalities
OrdinalityDescription
Primary
(where the weakness exists independent of other weaknesses)
+ Memberships
Section HelpThis 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.
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.975SFP Secondary Cluster: Architecture
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1418Comprehensive Categorization: Violation of Secure Design Principles
+ 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 closely associated with the term "Separation of Privilege." This term is used in several different ways in the industry, but they generally combine two closely related principles: compartmentalization (CWE-653) and using only one factor in a security decision (this entry). Proper compartmentalization implicitly introduces multiple factors into a security decision, but there can be cases in which multiple factors are required for authentication or other mechanisms that do not involve compartmentalization, such as performing all required checks on a submitted certificate. It is likely that CWE-653 and CWE-654 will provoke further discussion.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
ISA/IEC 62443Part 4-1Req SD-3
ISA/IEC 62443Part 4-1Req SD-4
ISA/IEC 62443Part 4-1Req SI-1
+ References
[REF-196] Jerome H. Saltzer and Michael D. Schroeder. "The Protection of Information in Computer Systems". Proceedings of the IEEE 63. 1975-09. <http://web.mit.edu/Saltzer/www/publications/protection/>.
[REF-535] Sean Barnum and Michael Gegick. "Separation of Privilege". 2005-12-06. <https://web.archive.org/web/20220126060047/https://www.cisa.gov/uscert/bsi/articles/knowledge/principles/separation-of-privilege>. URL validated: 2023-04-07.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2008-01-18
(CWE Draft 8, 2008-01-30)
Pascal MeunierPurdue University
+ Contributions
Contribution DateContributorOrganization
2023-04-25"Mapping CWE to 62443" Sub-Working GroupCWE-CAPEC ICS/OT SIG
Suggested mappings to ISA/IEC 62443.
+ Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Alternate_Terms, Common_Consequences, Relationships, Other_Notes, Weakness_Ordinalities
2009-01-12CWE Content TeamMITRE
updated Description, Name
2009-05-27CWE Content TeamMITRE
updated Relationships
2010-04-05CWE Content TeamMITRE
updated Related_Attack_Patterns
2011-06-01CWE Content TeamMITRE
updated Common_Consequences, Maintenance_Notes, Other_Notes
2012-05-11CWE Content TeamMITRE
updated Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2013-02-21CWE Content TeamMITRE
updated Potential_Mitigations
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Causal_Nature
2020-02-24CWE Content TeamMITRE
updated Relationships
2020-08-20CWE Content TeamMITRE
updated Related_Attack_Patterns
2020-12-10CWE Content TeamMITRE
updated Relationships
2021-03-15CWE Content TeamMITRE
updated Alternate_Terms, Maintenance_Notes
2022-10-13CWE Content TeamMITRE
updated References
2023-04-27CWE Content TeamMITRE
updated References, Relationships, Taxonomy_Mappings
2023-06-29CWE Content TeamMITRE
updated Mapping_Notes
2023-10-26CWE Content TeamMITRE
updated Observed_Examples
+ Previous Entry Names
Change DatePrevious Entry Name
2009-01-12Design Principle Violation: Reliance on a Single Factor in a Security Decision
Page Last Updated: July 16, 2024