CWE-607 Variante Borrador

Public Static Final Field References Mutable Object

This vulnerability occurs when a class exposes a public or protected static final field that points to a changeable object. Because the field's reference is constant but the object itself is not,…

Definición

What is CWE-607?

This vulnerability occurs when a class exposes a public or protected static final field that points to a changeable object. Because the field's reference is constant but the object itself is not, malicious code or even accidental code in other packages can modify the object's contents, violating the intended immutability.
The core issue is a misunderstanding of the `final` keyword in Java and similar languages. When applied to an object reference, `final` only guarantees that the reference itself cannot be reassigned to point to a different object. It does not protect the internal state of the object that the reference points to. If that object is mutable—like an array, a collection, or a custom class with public setters—its data can be freely altered, even through the `static final` field. To prevent this, developers must ensure true immutability. This involves either assigning the static final field to an inherently immutable object (like a `String` or a boxed primitive) or defensively wrapping mutable objects. For collections, use `Collections.unmodifiableList()`, `Map.copyOf()`, or similar methods to create an unmodifiable view or a deep copy before assignment. This practice encapsulates the mutable data and enforces the read-only intent of the public static field.
Impacto en el mundo real

Real-world CVEs caused by CWE-607

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

Here, an array (which is inherently mutable) is labeled public static final.

Vulnerable Java 
public static final String[] USER_ROLES;
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-607

  • Implementation Protect mutable objects by making them private. Restrict access to the getter and setter as well.
Señales de detección

How to detect CWE-607

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-607 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-607?

This vulnerability occurs when a class exposes a public or protected static final field that points to a changeable object. Because the field's reference is constant but the object itself is not, malicious code or even accidental code in other packages can modify the object's contents, violating the intended immutability.

¿Qué gravedad tiene CWE-607?

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-607?

MITRE lists the following affected platforms: Java.

¿Cómo puedo prevenir CWE-607?

Protect mutable objects by making them private. Restrict access to the getter and setter as well.

¿Cómo detecta y corrige Plexicus CWE-607?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-607 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-607?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/607.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-607

CWE-471 Padre

Modification of Assumed-Immutable Data (MAID)

This vulnerability occurs when an application fails to protect data it assumes cannot be changed, allowing an attacker to alter it.

CWE-472 Hermano

External Control of Assumed-Immutable Web Parameter

This vulnerability occurs when a web application incorrectly trusts data that appears to be fixed or hidden from the user, such as values…

CWE-473 Hermano

PHP External Variable Modification

This vulnerability occurs when a PHP application fails to properly validate or sanitize variables that originate from outside the…

Recursos

Further reading

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