CWE-453 Variante Borrador

Insecure Default Variable Initialization

This vulnerability occurs when software sets an internal variable to an insecure or unnecessarily weak default value during initialization, rather than using the most secure option available.

Definición

What is CWE-453?

This vulnerability occurs when software sets an internal variable to an insecure or unnecessarily weak default value during initialization, rather than using the most secure option available.
Insecure default initialization happens when a developer or framework assigns a starting value to a variable that is inherently vulnerable. Common examples include enabling debug modes, using weak cryptographic keys, granting excessive permissions, or turning security features off by default. This creates a hidden security gap because the system starts in a weakened state, often without the administrator or end-user being aware that they need to change a setting to be secure. To prevent this, developers should adopt a 'secure by default' design principle. This means the initial configuration should be the most restrictive and safest possible, requiring explicit action to loosen security, not the other way around. Always validate that security-critical variables like encryption settings, authentication flags, and privilege levels are initialized to their strongest values, and ensure documentation clearly warns against using insecure defaults.
Impacto en el mundo real

Real-world CVEs caused by CWE-453

  • CVE-2022-36349

    insecure default variable initialization in BIOS firmware for a hardware board allows DoS

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    This code attempts to login a user using credentials from a POST request:

  2. 2

    Because the $authorized variable is never initialized, PHP will automatically set $authorized to any value included in the POST request if register_globals is enabled. An attacker can send a POST request with an unexpected third value 'authorized' set to 'true' and gain authorized status without supplying valid credentials.

  3. 3

    Here is a fixed version:

  4. 4

    This code avoids the issue by initializing the $authorized variable to false and explicitly retrieving the login credentials from the $_POST variable. Regardless, register_globals should never be enabled and is disabled by default in current versions of PHP.

Ejemplo de código vulnerable

Vulnerable PHP

This code attempts to login a user using credentials from a POST request:

Vulnerable PHP 
```
// $user and $pass automatically set from POST request* 
  if (login_user($user,$pass)) {
  ```
  	$authorized = true;
  }
```
...* 
  
  if ($authorized) {
  ```
  	generatePage();
  }
Ejemplo de código seguro

Secure PHP

Here is a fixed version:

Seguro PHP 
$user = $_POST['user'];
  $pass = $_POST['pass'];
  $authorized = false;
  if (login_user($user,$pass)) {
  	$authorized = true;
  }
```
...*
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-453

  • System Configuration Disable or change default settings when they can be used to abuse the system. Since those default settings are shipped with the product they are likely to be known by a potential attacker who is familiar with the product. For instance, default credentials should be changed or the associated accounts should be disabled.
Señales de detección

How to detect CWE-453

SAST High

Ejecuta análisis estático (SAST) sobre el código buscando el patrón inseguro en el flujo de datos.

DAST Moderate

Ejecuta pruebas dinámicas de seguridad de aplicaciones (DAST) contra el endpoint en vivo.

Runtime Moderate

Vigila los logs en tiempo de ejecución para detectar trazas de excepción inusuales, entradas malformadas o intentos de bypass de autorización.

Code review Moderate

Revisión de código: marca cualquier código nuevo que maneje entrada desde esta superficie sin usar los helpers validados del framework.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-453 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-453?

This vulnerability occurs when software sets an internal variable to an insecure or unnecessarily weak default value during initialization, rather than using the most secure option available.

¿Qué gravedad tiene CWE-453?

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-453?

MITRE lists the following affected platforms: PHP.

¿Cómo puedo prevenir CWE-453?

Disable or change default settings when they can be used to abuse the system. Since those default settings are shipped with the product they are likely to be known by a potential attacker who is familiar with the product. For instance, default credentials should be changed or the associated accounts should be disabled.

¿Cómo detecta y corrige Plexicus CWE-453?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-453 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-453?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/453.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-453

CWE-1188 Padre

Initialization of a Resource with an Insecure Default

This vulnerability occurs when software uses an insecure default setting or value for a resource, assuming an administrator will change it…

Recursos

Further reading

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