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.
CWE-233 Base Incompleto
Improper Handling of Parameters
This vulnerability occurs when software fails to correctly process input that contains an unexpected number of parameters, missing fields, or undefined arguments. It often leads to crashes,…
Definición
What is CWE-233?
This vulnerability occurs when software fails to correctly process input that contains an unexpected number of parameters, missing fields, or undefined arguments. It often leads to crashes, unexpected behavior, or security bypasses.
At its core, this weakness is about poor input validation and error handling. When an application expects a specific set of data—like form fields, API parameters, or function arguments—but receives fewer, more, or undefined values, it must handle this gracefully. Without proper checks, the software might try to access non-existent data, causing errors like null pointer dereferences, out-of-bounds access, or logic flaws that attackers can exploit to crash the system or bypass security controls.
To prevent this, developers should implement strict input validation at all entry points. Always define and enforce the expected structure, count, and presence of all parameters. Use safe access patterns, such as checking for a parameter's existence before using it, and provide default values where appropriate. Robust error handling routines should catch and manage malformed requests without exposing sensitive debug information, ensuring the application remains stable and secure even when faced with unexpected input.
Impacto en el mundo real
Real-world CVEs caused by CWE-233
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
Identifica una ruta de código que maneje entrada no confiable sin validación.
- 2
Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.
- 3
Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.
- 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:
```
...*
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
// 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-233
- 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-233
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.)
Plexicus detecta automáticamente CWE-233 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.
Preguntas frecuentes ¿Qué es CWE-233?
¿Qué gravedad tiene CWE-233?
¿Qué lenguajes o plataformas se ven afectados por CWE-233?
¿Cómo puedo prevenir CWE-233?
¿Cómo detecta y corrige Plexicus CWE-233?
¿Dónde puedo aprender más sobre CWE-233?
Frequently asked questions
¿Qué es CWE-233?
This vulnerability occurs when software fails to correctly process input that contains an unexpected number of parameters, missing fields, or undefined arguments. It often leads to crashes, unexpected behavior, or security bypasses.
¿Qué gravedad tiene CWE-233?
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-233?
MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.
¿Cómo puedo prevenir CWE-233?
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-233?
El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-233 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-233?
MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/233.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.
Debilidades relacionadas
Weaknesses related to CWE-233
CWE-228 Padre
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,…
CWE-166 Hermano
Improper Handling of Missing Special Element
This vulnerability occurs when software expects a specific delimiter, terminator, or other special marker in its input but fails to…
CWE-167 Hermano
Improper Handling of Additional Special Element
This vulnerability occurs when software receives data from another component but fails to properly process or validate unexpected special…
CWE-168 Hermano
Improper Handling of Inconsistent Special Elements
This vulnerability occurs when software fails to correctly process input containing conflicting or mismatched special elements like…
CWE-229 Hermano
Improper Handling of Values
This vulnerability occurs when software fails to correctly process situations where input contains too few values, too many values, or…
CWE-237 Hermano
Improper Handling of Structural Elements
This vulnerability occurs when an application fails to properly validate, sanitize, or interpret the complex internal parts of structured…
CWE-241 Hermano
Improper Handling of Unexpected Data Type
This vulnerability occurs when software fails to properly validate or safely process data that arrives in an unexpected format. For…
CWE-234 Hijo
Failure to Handle Missing Parameter
This vulnerability occurs when a function or method receives fewer arguments than it expects. The function will still attempt to process…
CWE-235 Hijo
Improper Handling of Extra Parameters
This vulnerability occurs when a system fails to properly manage situations where it receives more parameters, fields, or arguments with…
Listo cuando tú lo estés
Deja de pagar por desarrollador.
Empieza a cerrar el bucle.
Plexicus es el ASPM nativo de IA que escanea, filtra, corrige, pentestea y explica — de forma autónoma. Desarrolladores ilimitados, repos ilimitados, acciones de IA de uso justo. Nivel gratuito real, €269/mo anual cuando estés listo.