CWE-484 Base Borrador Medium likelihood

Omitted Break Statement in Switch

This vulnerability occurs when a developer forgets to include a 'break' statement inside a switch-case block. Without it, the code execution 'falls through' and unintentionally runs the logic for…

Definición

What is CWE-484?

This vulnerability occurs when a developer forgets to include a 'break' statement inside a switch-case block. Without it, the code execution 'falls through' and unintentionally runs the logic for subsequent cases, leading to unexpected behavior.
A missing 'break' statement causes a switch block to fail its primary purpose: executing one distinct code path. Instead, it cascades from the matched case into the code for the cases below it. This 'fall-through' behavior is a common logic error that can bypass critical security checks, corrupt data, or trigger functions that should only run under specific conditions. While some languages allow intentional fall-through for specific patterns, omitting 'break' by mistake is a frequent source of bugs. To prevent this, developers should adopt a defensive coding style, such as always adding a 'break' as the default action and using linter rules to flag missing statements. Explicitly commenting any intentional fall-throughs makes the code safer and more maintainable.
Impacto en el mundo real

Real-world CVEs caused by CWE-484

Todavía no hay CVEs públicos enlazados a esta CWE en el catálogo de MITRE.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    Identifica una ruta de código que maneje entrada no confiable sin validación.

  2. 2

    Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.

  3. 3

    Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.

  4. 4

    Itera hasta que la respuesta filtre datos, ejecute código del atacante o escale privilegios.

Ejemplo de código vulnerable

Vulnerable Java

In both of these examples, a message is printed based on the month passed into the function:

Vulnerable Java 
public void printMessage(int month){
  		switch (month) {
  				case 1: print("January");
  				case 2: print("February");
  				case 3: print("March");
  				case 4: print("April");
  				case 5: print("May");
  				case 6: print("June");
  				case 7: print("July");
  				case 8: print("August");
  				case 9: print("September");
  				case 10: print("October");
  				case 11: print("November");
  				case 12: print("December");
  		}
  		println(" is a great month");
  }
Ejemplo de código seguro

Secure pseudo

Seguro 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.
Lista de prevención

How to prevent CWE-484

  • Implementation Omitting a break statement so that one may fall through is often indistinguishable from an error, and therefore should be avoided. If you need to use fall-through capabilities, make sure that you have clearly documented this within the switch statement, and ensure that you have examined all the logical possibilities.
  • Implementation The functionality of omitting a break statement could be clarified with an if statement. This method is much safer.
Señales de detección

How to detect CWE-484

White Box

Omission of a break statement might be intentional, in order to support fallthrough. Automated detection methods might therefore be erroneous. Semantic understanding of expected product behavior is required to interpret whether the code is correct.

Black Box

Since this weakness is associated with a code construct, it would be indistinguishable from other errors that produce the same behavior.

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.)

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-484 y abre un PR de corrección en menos de 60 segundos.

Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.

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Preguntas frecuentes

Frequently asked questions

¿Qué es CWE-484?

This vulnerability occurs when a developer forgets to include a 'break' statement inside a switch-case block. Without it, the code execution 'falls through' and unintentionally runs the logic for subsequent cases, leading to unexpected behavior.

¿Qué gravedad tiene CWE-484?

MITRE califica la probabilidad de explotación como Media — la explotación es realista pero suele requerir condiciones específicas.

¿Qué lenguajes o plataformas se ven afectados por CWE-484?

MITRE lists the following affected platforms: C, C++, Java, C#, PHP.

¿Cómo puedo prevenir CWE-484?

Omitting a break statement so that one may fall through is often indistinguishable from an error, and therefore should be avoided. If you need to use fall-through capabilities, make sure that you have clearly documented this within the switch statement, and ensure that you have examined all the logical possibilities. The functionality of omitting a break statement could be clarified with an if statement. This method is much safer.

¿Cómo detecta y corrige Plexicus CWE-484?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-484 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.

¿Dónde puedo aprender más sobre CWE-484?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/484.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-484

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CWE-1066 Hermano

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Recursos

Further reading

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