CWE-103 Variante Borrador

Struts: Incomplete validate() Method Definition

This vulnerability occurs in a Struts application when a validator form either completely omits a validate() method or includes one but fails to call super.validate() within it.

Definición

What is CWE-103?

This vulnerability occurs in a Struts application when a validator form either completely omits a validate() method or includes one but fails to call super.validate() within it.
In the Struts validation framework, the super.validate() call is essential because it triggers the framework's built-in validation logic. Without this call, the framework cannot process the validation rules defined for the form, effectively leaving the form's input unchecked and allowing potentially malicious or malformed data to proceed. As a result, the entire validation layer for that specific form is disabled, creating a security gap where attackers can bypass intended data checks. Developers must ensure every custom validate() method explicitly invokes super.validate() to maintain the security chain and enforce all configured validation constraints.
Impacto en el mundo real

Real-world CVEs caused by CWE-103

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 the following Java example the class RegistrationForm is a Struts framework ActionForm Bean that will maintain user input data from a registration webpage for an online business site. The user will enter registration data and the RegistrationForm bean in the Struts framework will maintain the user data. Tthe RegistrationForm class implements the validate method to validate the user input entered into the form.

Vulnerable Java 
public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {
  	// private variables for registration form
  	private String name;
  	private String email;
  	...
  	public RegistrationForm() {
  		super();
  	}
  	public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
  		ActionErrors errors = new ActionErrors();
  		if (getName() == null || getName().length() < 1) {
  			errors.add("name", new ActionMessage("error.name.required"));
  		}
  		return errors;
  	}
  	// getter and setter methods for private variables
  	...
  }
Ejemplo de código seguro

Secure Java

Although the validate method is implemented in this example the method does not call the validate method of the ValidatorForm parent class with a call super.validate(). Without the call to the parent validator class only the custom validation will be performed and the default validation will not be performed. The following example shows that the validate method of the ValidatorForm class is called within the implementation of the validate method.

Seguro Java 
public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {
  		// private variables for registration form
  		private String name;
  		private String email;
  		...
  		public RegistrationForm() {
  			super();
  		}
  		public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
  			ActionErrors errors = super.validate(mapping, request);
  			if (errors == null) {
  				errors = new ActionErrors();
  			}
  		if (getName() == null || getName().length() < 1) {
  			errors.add("name", new ActionMessage("error.name.required"));
  		}
  		return errors;
  }
  	// getter and setter methods for private variables
  	...
  }
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-103

  • Implementation Implement the validate() method and call super.validate() within that method.
Señales de detección

How to detect CWE-103

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-103 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-103?

This vulnerability occurs in a Struts application when a validator form either completely omits a validate() method or includes one but fails to call super.validate() within it.

¿Qué gravedad tiene CWE-103?

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-103?

MITRE lists the following affected platforms: Java.

¿Cómo puedo prevenir CWE-103?

Implement the validate() method and call super.validate() within that method.

¿Cómo detecta y corrige Plexicus CWE-103?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-103 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-103?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/103.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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