CWE-571 Base Brouillon

Expression is Always True

This vulnerability occurs when code contains a conditional expression that will always evaluate to 'true', making the check ineffective and potentially bypassing critical security or logic gates.

Définition

What is CWE-571?

This vulnerability occurs when code contains a conditional expression that will always evaluate to 'true', making the check ineffective and potentially bypassing critical security or logic gates.
An 'always true' expression often stems from logic errors where a developer compares a variable against itself, uses a constant instead of a variable, or creates a condition that can never be false due to prior operations. For example, checking `if (x > 5 || x >= 5)` is redundant because the second part is always true if the first is false. This dead code not only clutters the logic but can silently disable security validations, access controls, or error-handling routines, creating a false sense of security. From a security perspective, these flaws are particularly dangerous in authentication checks, input validation, or privilege escalation guards, as they may allow unauthorized actions to proceed. To prevent this, developers should audit conditional logic for tautologies, use static analysis tools to detect unreachable code, and carefully review comparisons involving constants or variables that may have been modified earlier in the function flow.
Impact réel

Real-world CVEs caused by CWE-571

Aucune référence CVE publique n'est liée à ce CWE dans le catalogue MITRE pour le moment.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    Identifier un chemin de code qui traite des entrées non fiables sans validation.

  2. 2

    Élaborer une charge utile qui exploite le comportement non sécurisé — injection, traversal, débordement ou abus de logique.

  3. 3

    Délivrer la charge utile via une requête normale et observer la réaction de l'application.

  4. 4

    Itérer jusqu'à ce que la réponse divulgue des données, exécute le code de l'attaquant ou élève les privilèges.

Exemple de code vulnérable

Vulnerable Java

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.

Vulnérable 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 */* 
  				...}}
Exemple de code sécurisé

Secure pseudo

Sécurisé pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Liste de contrôle de prévention

How to prevent CWE-571

  • Testing Use Static Analysis tools to spot such conditions.
Signaux de détection

How to detect CWE-571

Automated Static Analysis High

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.)

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-571 et ouvre une PR de correction en moins de 60 secondes.

Codex Remedium analyse chaque commit, identifie cette faiblesse précise et livre une pull request prête à être relue avec le correctif. Pas de tickets. Pas de transferts.

Obtenir une démo Essayer Plexicus gratuitement
Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-571 ?

This vulnerability occurs when code contains a conditional expression that will always evaluate to 'true', making the check ineffective and potentially bypassing critical security or logic gates.

Quelle est la gravité de CWE-571 ?

MITRE n'a pas publié de note de probabilité d'exploitation pour cette faiblesse. Traitez-la comme un impact moyen jusqu'à ce que votre modèle de menace prouve le contraire.

Quels langages ou plateformes sont affectés par CWE-571 ?

MITRE n'a pas spécifié les plateformes affectées pour ce CWE — il peut s'appliquer à la plupart des stacks applicatives.

Comment puis-je prévenir CWE-571 ?

Use Static Analysis tools to spot such conditions.

Comment Plexicus détecte et corrige CWE-571 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-571 à chaque commit. Lorsqu'une correspondance est trouvée, notre agent Codex Remedium ouvre une PR de correction avec le code corrigé, les tests et un résumé d'une ligne pour le relecteur.

Où puis-je en savoir plus sur CWE-571 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/571.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-571

CWE-710 Parent

Improper Adherence to Coding Standards

This weakness occurs when developers don't consistently follow established coding standards and best practices, which can introduce…

CWE-1041 Frère

Use of Redundant Code

This weakness occurs when a codebase contains identical or nearly identical logic duplicated across multiple functions, methods, or…

CWE-1044 Frère

Architecture with Number of Horizontal Layers Outside of Expected Range

This occurs when a software system is built with either too many or too few distinct architectural layers, falling outside a recommended…

CWE-1048 Frère

Invokable Control Element with Large Number of Outward Calls

This weakness occurs when a single function, method, or callable code block makes an excessively high number of calls to other objects or…

CWE-1059 Frère

Insufficient Technical Documentation

This weakness occurs when a software or hardware product lacks comprehensive technical documentation. Missing or incomplete details about…

CWE-1061 Frère

Insufficient Encapsulation

This weakness occurs when a software component exposes too much of its internal workings, such as data structures or implementation logic.…

CWE-1065 Frère

Runtime Resource Management Control Element in a Component Built to Run on Application Servers

This weakness occurs when an application built to run on a managed application server bypasses the server's high-level APIs and instead…

CWE-1066 Frère

Missing Serialization Control Element

This weakness occurs when a class or data structure is marked as serializable but lacks the required control methods to properly handle…

CWE-1068 Frère

Inconsistency Between Implementation and Documented Design

This weakness occurs when the actual code implementation deviates from the intended design described in its official documentation,…

Ressources

Further reading

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