CWE-228 Clase Incompleto

Improper Handling of Syntactically Invalid Structure

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.

Definición

What is CWE-228?

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.
When software expects data in a specific format—like JSON, XML, protocol messages, or file structures—it must rigorously validate that incoming input matches that exact syntax. If the code assumes the input is always well-formed and doesn't implement proper error handling for malformed data, attackers can exploit this by sending deliberately invalid structures. This can trigger unhandled exceptions, cause the application to crash, or bypass security checks that rely on correct parsing. To prevent this, developers should implement strict validation at all data entry points, using well-tested parsers and libraries instead of custom logic. Always define clear error-handling routines that safely reject invalid input without exposing internal details, and design systems to fail securely—defaulting to a denied state—when encountering unexpected syntax. Regular fuzz testing with invalid inputs helps uncover these hidden parsing weaknesses before attackers do.
Impacto en el mundo real

Real-world CVEs caused by CWE-228

  • CVE-2004-0270

    Anti-virus product has assert error when line length is non-numeric.

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

This Android application has registered to handle a URL when sent an intent:

Vulnerable Java 
```
...* 
  IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL");
  MyReceiver receiver = new MyReceiver();
  registerReceiver(receiver, filter);
  
   *...* 
  
  public class UrlHandlerReceiver extends BroadcastReceiver {
  ```
  		@Override
  		public void onReceive(Context context, Intent intent) {
  				if("com.example.URLHandler.openURL".equals(intent.getAction())) {
  					String URL = intent.getStringExtra("URLToOpen");
  					int length = URL.length();
```
...* 
  				}}}
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-228

  • 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.
Señales de detección

How to detect CWE-228

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-228 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-228?

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.

¿Qué gravedad tiene CWE-228?

MITRE no ha publicado una calificación de probabilidad de explotación para esta debilidad. Trátala como de impacto medio hasta que tu modelo de amenazas demuestre lo contrario.

¿Qué lenguajes o plataformas se ven afectados por CWE-228?

MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.

¿Cómo puedo prevenir CWE-228?

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.

¿Cómo detecta y corrige Plexicus CWE-228?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-228 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-228?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/228.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

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Recursos

Further reading

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