CWE-369 Base Brouillon Medium likelihood

Divide By Zero

A divide-by-zero error occurs when software attempts to perform a division operation where the denominator is zero.

Définition

What is CWE-369?

A divide-by-zero error occurs when software attempts to perform a division operation where the denominator is zero.
This flaw typically happens when user input, external data, or an unexpected program state introduces a zero value into a calculation where it wasn't anticipated. It's especially common in functions handling physical dimensions—like size, length, or coordinates—or in mathematical routines that don't validate their inputs. Without proper checks, the division triggers a runtime error that can crash the application or create an unstable state. Proactively preventing this requires validating all inputs and implementing safeguards before any division operation. While SAST tools can flag the dangerous pattern, Plexicus uses AI to analyze the context and suggest the specific guard clauses or error-handling code needed to fix it, turning a generic warning into an actionable fix. Managing these validation points across a large codebase is challenging; an ASPM platform like Plexicus helps track and prioritize these flaws for consistent remediation.
Impact réel

Real-world CVEs caused by CWE-369

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    The following Java example contains a function to compute an average but does not validate that the input value used as the denominator is not zero. This will create an exception for attempting to divide by zero. If this error is not handled by Java exception handling, unexpected results can occur.

  2. 2

    By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. The following Java code example will validate the input value, output an error message, and throw an exception.

  3. 3

    The following C/C++ example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

  4. 4

    By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. If the method is called and a zero is passed as the second argument a DivideByZero error will be thrown and should be caught by the calling block with an output message indicating the error.

  5. 5

    The following C# example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

Exemple de code vulnérable

Vulnerable Java

The following Java example contains a function to compute an average but does not validate that the input value used as the denominator is not zero. This will create an exception for attempting to divide by zero. If this error is not handled by Java exception handling, unexpected results can occur.

Vulnérable Java 
public int computeAverageResponseTime (int totalTime, int numRequests) {
  	return totalTime / numRequests;
  }
Exemple de code sécurisé

Secure Java

By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. The following Java code example will validate the input value, output an error message, and throw an exception.

Sécurisé Java 
public int computeAverageResponseTime (int totalTime, int numRequests) throws ArithmeticException {
  	if (numRequests == 0) {
  		System.out.println("Division by zero attempted!");
  		throw ArithmeticException;
  	}
  	return totalTime / numRequests;
  }
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-369

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Signaux de détection

How to detect CWE-369

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.)

Fuzzing High

Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-369 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-369 ?

A divide-by-zero error occurs when software attempts to perform a division operation where the denominator is zero.

Quelle est la gravité de CWE-369 ?

MITRE évalue la probabilité d'exploitation comme Moyenne — l'exploitation est réaliste mais nécessite généralement des conditions spécifiques.

Quels langages ou plateformes sont affectés par CWE-369 ?

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-369 ?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Comment Plexicus détecte et corrige CWE-369 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-369 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-369 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/369.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

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Weaknesses related to CWE-369

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Ressources

Further reading

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