Common Weakness Enumeration

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CWE-655: Insufficient Psychological Acceptability

Weakness ID: 655
Abstraction: Class
Structure: Simple
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+ Description
The product has a protection mechanism that is too difficult or inconvenient to use, encouraging non-malicious users to disable or bypass the mechanism, whether by accident or on purpose.
+ 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)
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
+ 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.
Architecture and Design
+ 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.


Class: Not Language-Specific (Undetermined Prevalence)

+ 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.
Access Control

Technical Impact: Bypass Protection Mechanism

By bypassing the security mechanism, a user might leave the system in a less secure state than intended by the administrator, making it more susceptible to compromise.
+ Demonstrative Examples

Example 1

In "Usability of Security: A Case Study" [REF-540], the authors consider human factors in a cryptography product. Some of the weakness relevant discoveries of this case study were: users accidentally leaked sensitive information, could not figure out how to perform some tasks, thought they were enabling a security option when they were not, and made improper trust decisions.

Example 2

Enforcing complex and difficult-to-remember passwords that need to be frequently changed for access to trivial resources, e.g., to use a black-and-white printer. Complex password requirements can also cause users to store the passwords in an unsafe manner so they don't have to remember them, such as using a sticky note or saving them in an unencrypted file.

Example 3

Some CAPTCHA utilities produce images that are too difficult for a human to read, causing user frustration.

+ Potential Mitigations

Phase: Testing

Where possible, perform human factors and usability studies to identify where your product's security mechanisms are difficult to use, and why.

Phase: Architecture and Design

Make the security mechanism as seamless as possible, while also providing the user with sufficient details when a security decision produces unexpected results.
+ Weakness Ordinalities
(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.
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.995SFP Secondary Cluster: Feature
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1379ICS Operations (& Maintenance): Human factors in ICS environments
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-with-Review

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction


This CWE entry is a Class and might have Base-level children that would be more appropriate


Examine children of this entry to see if there is a better fit
+ Notes


This weakness covers many security measures causing user inconvenience, requiring effort or causing frustration, that are disproportionate to the risks or value of the protected assets, or that are perceived to be ineffective.


The Taxonomy_Mappings to ISA/IEC 62443 were added in CWE 4.10, but they are still under review and might change in future CWE versions. These draft mappings were performed by members of the "Mapping CWE to 62443" subgroup of the CWE-CAPEC ICS/OT Special Interest Group (SIG), and their work is incomplete as of CWE 4.10. The mappings are included to facilitate discussion and review by the broader ICS/OT community, and they are likely to change in future CWE versions.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
ISA/IEC 62443Part 2-1Req
ISA/IEC 62443Part 4-1Req SD-4
+ References
[REF-196] Jerome H. Saltzer and Michael D. Schroeder. "The Protection of Information in Computer Systems". Proceedings of the IEEE 63. 1975-09. <>.
[REF-539] Sean Barnum and Michael Gegick. "Psychological Acceptability". 2005-09-15. <>. URL validated: 2023-04-07.
[REF-540] J. D. Tygar and Alma Whitten. "Usability of Security: A Case Study". SCS Technical Report Collection, CMU-CS-98-155. 1998-12-15. <>.
[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 14: Poor Usability." Page 217. McGraw-Hill. 2010.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
(CWE Draft 8, 2008-01-30)
Pascal MeunierPurdue University
+ Contributions
Contribution DateContributorOrganization
2022-07-16Nicolai Plum
Provided new links for a reference that improved multiple CWEs.
(CWE 4.10, 2023-01-31)
"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 Common_Consequences, Relationships, Other_Notes, Weakness_Ordinalities
2009-01-12CWE Content TeamMITRE
updated Description, Name
2009-05-27CWE Content TeamMITRE
updated Name
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated References, Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2014-06-23CWE Content TeamMITRE
updated Demonstrative_Examples
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Causal_Nature
2020-02-24CWE Content TeamMITRE
updated Relationships, Time_of_Introduction
2022-04-28CWE Content TeamMITRE
updated Relationships
2022-10-13CWE Content TeamMITRE
updated References
2023-01-31CWE Content TeamMITRE
updated Description, Maintenance_Notes, Taxonomy_Mappings
2023-04-27CWE Content TeamMITRE
updated References, Relationships, Time_of_Introduction, Type
2023-06-29CWE Content TeamMITRE
updated Mapping_Notes
+ Previous Entry Names
Change DatePrevious Entry Name
2009-01-12Design Principle Violation: Failure to Satisfy Psychological Acceptability
2009-05-27Failure to Satisfy Psychological Acceptability
Page Last Updated: June 29, 2023