CWE

Common Weakness Enumeration

A community-developed list of SW & HW weaknesses that can become vulnerabilities

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Home > CWE List > CWE-636: Not Failing Securely ('Failing Open') (4.16)  
ID

CWE-636: Not Failing Securely ('Failing Open')

Weakness ID: 636
Vulnerability Mapping: ALLOWED This CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: Class 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.
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+ Description
When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.
+ Extended Description
By entering a less secure state, the product inherits the weaknesses associated with that state, making it easier to compromise. At the least, it causes administrators to have a false sense of security. This weakness typically occurs as a result of wanting to "fail functional" to minimize administration and support costs, instead of "failing safe."
+ Alternate Terms
Failing Open
+ 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.
Scope Impact Likelihood
Access Control

Technical Impact: Bypass Protection Mechanism

Intended access restrictions can be bypassed, which is often contradictory to what the product's administrator expects.
+ Potential Mitigations

Phase: Architecture and Design

Subdivide and allocate resources and components so that a failure in one part does not affect the entire product.
+ Relationships
Section Help 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 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. 657 Violation of Secure Design Principles
ChildOf Class 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. 755 Improper Handling of Exceptional Conditions
ParentOf 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. 455 Non-exit on Failed Initialization
PeerOf 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. 280 Improper Handling of Insufficient Permissions or Privileges
+ 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.
Phase Note
Architecture and Design
Implementation
+ 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)

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Class: ICS/OT (Undetermined Prevalence)

+ Demonstrative Examples

Example 1

Switches may revert their functionality to that of hubs when the table used to map ARP information to the switch interface overflows, such as when under a spoofing attack. This results in traffic being broadcast to an eavesdropper, instead of being sent only on the relevant switch interface. To mitigate this type of problem, the developer could limit the number of ARP entries that can be recorded for a given switch interface, while other interfaces may keep functioning normally. Configuration options can be provided on the appropriate actions to be taken in case of a detected failure, but safe defaults should be used.


+ Observed Examples
Reference Description
The failure of connection attempts in a web browser resets DNS pin restrictions. An attacker can then bypass the same origin policy by rebinding a domain name to a different IP address. This was an attempt to "fail functional."
Incorrect prioritization leads to the selection of a weaker cipher. Although it is not known whether this issue occurred in implementation or design, it is feasible that a poorly designed algorithm could be a factor.
+ Weakness Ordinalities
Ordinality Description
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.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 728 OWASP Top Ten 2004 Category A7 - Improper Error Handling
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 961 SFP Secondary Cluster: Incorrect Exception Behavior
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1369 ICS Supply Chain: IT/OT Convergence/Expansion
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1418 Comprehensive 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

Rationale:

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

Comments:

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

Research Gap

Since design issues are hard to fix, they are rarely publicly reported, so there are few CVE examples of this problem as of January 2008. Most publicly reported issues occur as the result of an implementation error instead of design, such as CVE-2005-3177 (Improper handling of large numbers of resources) or CVE-2005-2969 (inadvertently disabling a verification step, leading to selection of a weaker protocol).
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
OWASP Top Ten 2004 A7 CWE More Specific Improper Error Handling
+ 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-522] Sean Barnum and Michael Gegick. "Failing Securely". 2005-12-05. <https://web.archive.org/web/20221017053210/https://www.cisa.gov/uscert/bsi/articles/knowledge/principles/failing-securely>. URL validated: 2023-04-07.
+ Content History
+ Submissions
Submission Date Submitter Organization
2008-01-18
(CWE Draft 8, 2008-01-30)
Pascal Meunier Purdue University
+ Modifications
Modification Date Modifier Organization
2008-07-01 Eric Dalci Cigital
updated Time_of_Introduction
2008-09-08 CWE Content Team MITRE
updated Common_Consequences, Description, Name, Relationships, Taxonomy_Mappings, Weakness_Ordinalities
2009-01-12 CWE Content Team MITRE
updated Description, Name
2009-03-10 CWE Content Team MITRE
updated Relationships
2009-05-27 CWE Content Team MITRE
updated Name
2010-12-13 CWE Content Team MITRE
updated Research_Gaps
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
2012-05-11 CWE Content Team MITRE
updated Relationships
2012-10-30 CWE Content Team MITRE
updated Potential_Mitigations
2014-07-30 CWE Content Team MITRE
updated Relationships
2017-11-08 CWE Content Team MITRE
updated Applicable_Platforms, Causal_Nature, Relationships
2020-02-24 CWE Content Team MITRE
updated Relationships
2022-04-28 CWE Content Team MITRE
updated Relationships
2022-10-13 CWE Content Team MITRE
updated References
2023-01-31 CWE Content Team MITRE
updated Applicable_Platforms
2023-04-27 CWE Content Team MITRE
updated References, Relationships
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes
2023-10-26 CWE Content Team MITRE
updated Demonstrative_Examples
+ Previous Entry Names
Change Date Previous Entry Name
2008-09-09 Design Principle Violation: Not Failing Securely
2009-01-12 Design Principle Violation: Not Failing Securely (aka 'Failing Open')
2009-05-27 Not Failing Securely (aka 'Failing Open')
Page Last Updated: November 19, 2024