CWE-637 Clase Borrador

Unnecessary Complexity in Protection Mechanism (Not Using 'Economy of Mechanism')

This weakness occurs when a security feature is implemented with excessive complexity, creating unnecessary risk. Overly intricate protection mechanisms are harder to understand, configure, and…

Definición

What is CWE-637?

This weakness occurs when a security feature is implemented with excessive complexity, creating unnecessary risk. Overly intricate protection mechanisms are harder to understand, configure, and implement correctly, often leading to security gaps and misconfigurations.
Security controls should follow the principle of 'economy of mechanism'—the simpler they are, the more reliable they become. Complex designs increase the chance of implementation errors, compatibility issues, and mismatches between the intended security model and its real-world deployment. Developers are more likely to correctly implement, test, and maintain straightforward solutions. This principle also applies to data structures and validation logic. Overly complex data specifications force you to write equally complex validation code, which is prone to bugs. Whenever possible, favor simple system architectures and data models, as they naturally require simpler and more robust security checks.
Impacto en el mundo real

Real-world CVEs caused by CWE-637

  • CVE-2007-6067

    Support for complex regular expressions leads to a resultant algorithmic complexity weakness (CWE-407).

  • CVE-2007-1552

    Either a filename extension and a Content-Type header could be used to infer the file type, but the developer only checks the Content-Type, enabling unrestricted file upload (CWE-434).

  • CVE-2007-6479

    In Apache environments, a "filename.php.gif" can be redirected to the PHP interpreter instead of being sent as an image/gif directly to the user. Not knowing this, the developer only checks the last extension of a submitted filename, enabling arbitrary code execution.

  • CVE-2005-2148

    The developer cleanses the $_REQUEST superglobal array, but PHP also populates $_GET, allowing attackers to bypass the protection mechanism and conduct SQL injection attacks against code that uses $_GET.

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 pseudo

MITRE no ha publicado un ejemplo de código para esta CWE. El patrón siguiente es ilustrativo — consulta Recursos para referencias canónicas.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
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-637

  • Architecture and Design Avoid complex security mechanisms when simpler ones would meet requirements. Avoid complex data models, and unnecessarily complex operations. Adopt architectures that provide guarantees, simplify understanding through elegance and abstraction, and that can be implemented similarly. Modularize, isolate and do not trust complex code, and apply other secure programming principles on these modules (e.g., least privilege) to mitigate vulnerabilities.
Señales de detección

How to detect CWE-637

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-637 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-637?

This weakness occurs when a security feature is implemented with excessive complexity, creating unnecessary risk. Overly intricate protection mechanisms are harder to understand, configure, and implement correctly, often leading to security gaps and misconfigurations.

¿Qué gravedad tiene CWE-637?

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-637?

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

¿Cómo puedo prevenir CWE-637?

Avoid complex security mechanisms when simpler ones would meet requirements. Avoid complex data models, and unnecessarily complex operations. Adopt architectures that provide guarantees, simplify understanding through elegance and abstraction, and that can be implemented similarly. Modularize, isolate and do not trust complex code, and apply other secure programming principles on these modules (e.g., least privilege) to mitigate vulnerabilities.

¿Cómo detecta y corrige Plexicus CWE-637?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-637 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-637?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/637.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-637

CWE-657 Padre

Violation of Secure Design Principles

This weakness occurs when a system's architecture or design fails to follow fundamental security principles, creating a flawed foundation…

CWE-1192 Hermano

Improper Identifier for IP Block used in System-On-Chip (SOC)

This weakness occurs when a System-on-Chip (SoC) lacks a secure, unique, and permanent identifier for its internal hardware components (IP…

CWE-1395 Hermano

Dependency on Vulnerable Third-Party Component

This vulnerability occurs when your software relies on an external library, framework, or module that contains known security flaws.

CWE-250 Hermano

Execution with Unnecessary Privileges

This vulnerability occurs when software runs with higher permissions than it actually needs to perform its tasks. This excessive privilege…

CWE-636 Hermano

Not Failing Securely ('Failing Open')

This vulnerability occurs when a system, upon encountering an error or failure, defaults to its least secure configuration instead of a…

CWE-638 Hermano

Not Using Complete Mediation

This vulnerability occurs when software fails to verify access permissions every single time a user or process tries to use a resource.…

CWE-653 Hermano

Improper Isolation or Compartmentalization

This vulnerability occurs when an application fails to enforce strong boundaries between components that operate at different security…

CWE-654 Hermano

Reliance on a Single Factor in a Security Decision

This vulnerability occurs when a system's security check depends almost entirely on just one condition, object, or piece of data to decide…

CWE-655 Hermano

Insufficient Psychological Acceptability

This weakness occurs when security features are so cumbersome or confusing that well-intentioned users feel forced to turn them off or…

Recursos

Further reading

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