CWE

Common Weakness Enumeration

A Community-Developed List of Software & Hardware Weakness Types

CWE Top 25 Most Dangerous Weaknesses
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ID

CWE-571: Expression is Always True

Weakness ID: 571
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The software contains an expression that will always evaluate to true.
+ 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.710Improper Adherence to Coding Standards
CanPrecedeBaseBase - 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.561Dead Code
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.569Expression Issues
+ 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
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: Language-Independent (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.
ScopeImpactLikelihood
Other

Technical Impact: Quality Degradation; Varies by Context

+ Demonstrative Examples

Example 1

In the following Java example the updateInventory() method used within an e-business product ordering/inventory application will check if the input product number is in the store or in the warehouse. If the product is found, the method will update the store or warehouse database as well as the aggregate product database. If the product is not found, the method intends to do some special processing without updating any database.

(bad code)
Example Language: Java 

public void updateInventory(String productNumber) {
boolean isProductAvailable = false;
boolean isDelayed = false;

if (productInStore(productNumber)) {
isProductAvailable = true;
updateInStoreDatabase(productNumber);
}
else if (productInWarehouse(productNumber)) {
isProductAvailable = true;
updateInWarehouseDatabase(productNumber);
}
else {
isProductAvailable = true;
}

if ( isProductAvailable ) {
updateProductDatabase(productNumber);
}
else if ( isDelayed ) {

/* Warn customer about delay before order processing */
...
}
}

However, the method never sets the isDelayed variable and instead will always update the isProductAvailable variable to true. The result is that the predicate testing the isProductAvailable boolean will always evaluate to true and therefore always update the product database. Further, since the isDelayed variable is initialized to false and never changed, the expression always evaluates to false and the customer will never be warned of a delay on their product.

+ Potential Mitigations

Phase: Testing

Use Static Analysis tools to spot such conditions.
+ 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.747CERT C Secure Coding Standard (2008) Chapter 14 - Miscellaneous (MSC)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.883CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.998SFP Secondary Cluster: Glitch in Computation
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1307CISQ Quality Measures - Maintainability
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1308CISQ Quality Measures - Security
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CERT C Secure CodingMSC00-CCompile cleanly at high warning levels
Software Fault PatternsSFP1Glitch in computation
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2006-12-15CWE Community
Submitted by members of the CWE community to extend early CWE versions
+ Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes
2008-11-24CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2009-07-27CWE Content TeamMITRE
updated Demonstrative_Examples, Other_Notes, Potential_Mitigations
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2011-09-13CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2012-05-11CWE Content TeamMITRE
updated Relationships
2014-07-30CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Relationships, Taxonomy_Mappings
2020-02-24CWE Content TeamMITRE
updated Relationships, Type
2020-08-20CWE Content TeamMITRE
updated Relationships
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Page Last Updated: July 20, 2021