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Common Weakness Enumeration

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Home > CWE List > CWE-571: Expression is Always True (4.16)  
ID

CWE-571: Expression is Always True

Weakness ID: 571
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 contains an expression that will always evaluate to true.
+ 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
Other

Technical Impact: Quality Degradation; Varies by Context

+ Potential Mitigations

Phase: Testing

Use Static Analysis tools to spot such conditions.
+ 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 Pillar Pillar - 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. 710 Improper Adherence to Coding Standards
CanPrecede 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. 561 Dead Code
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 "Software Development" (CWE-699)
Nature Type ID Name
MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 569 Expression 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.
Phase Note
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)

+ 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.


+ Detection Methods

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

+ 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. 747 CERT C Secure Coding Standard (2008) Chapter 14 - Miscellaneous (MSC)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 883 CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 998 SFP Secondary Cluster: Glitch in Computation
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1307 CISQ Quality Measures - Maintainability
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1308 CISQ Quality Measures - Security
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1412 Comprehensive Categorization: Poor Coding Practices
+ 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.
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
CERT C Secure Coding MSC00-C Compile cleanly at high warning levels
Software Fault Patterns SFP1 Glitch in computation
+ Content History
+ Submissions
Submission Date Submitter Organization
2006-12-15
(CWE Draft 5, 2006-12-15)
CWE Community
Submitted by members of the CWE community to extend early CWE versions
+ Modifications
Modification Date Modifier Organization
2008-07-01 Eric Dalci Cigital
updated Potential_Mitigations, Time_of_Introduction
2008-09-08 CWE Content Team MITRE
updated Relationships, Other_Notes
2008-11-24 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2009-07-27 CWE Content Team MITRE
updated Demonstrative_Examples, Other_Notes, Potential_Mitigations
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
2011-06-27 CWE Content Team MITRE
updated Common_Consequences
2011-09-13 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2012-05-11 CWE Content Team MITRE
updated Relationships
2014-07-30 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2017-11-08 CWE Content Team MITRE
updated Applicable_Platforms, Relationships, Taxonomy_Mappings
2020-02-24 CWE Content Team MITRE
updated Relationships, Type
2020-08-20 CWE Content Team MITRE
updated Relationships
2023-01-31 CWE Content Team MITRE
updated Description
2023-04-27 CWE Content Team MITRE
updated Detection_Factors, Relationships
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes
Page Last Updated: November 19, 2024