CWE-1284 Base Incompleto

Improper Validation of Specified Quantity in Input

This vulnerability occurs when an application accepts user input meant to define a quantity—like a number, size, or count—but fails to properly check if that value is safe and reasonable before…

Definición

What is CWE-1284?

This vulnerability occurs when an application accepts user input meant to define a quantity—like a number, size, or count—but fails to properly check if that value is safe and reasonable before using it.
Applications constantly handle user-defined quantities: file sizes to upload, lengths for arrays, loop iteration counts, or prices for transactions. If your code trusts these numbers without scrutiny, it can be tricked into performing dangerous actions. Attackers exploit this by submitting extreme or malicious values—like a negative number, an impossibly large size, or zero—to manipulate the program's logic, crash it, or force it into an unstable state. Failing to validate quantities has direct consequences. Your application might allocate all available memory based on a huge size, perform a calculation that leads to an integer overflow, or enter an infinite loop. This opens the door to denial-of-service, buffer overflows, or logic flaws that compromise security. Always treat any user-supplied quantity as untrusted and enforce strict rules for minimums, maximums, and expected ranges before the value is used in any operation.
Impacto en el mundo real

Real-world CVEs caused by CWE-1284

  • CVE-2019-19911

    Chain: Python library does not limit the resources used to process images that specify a very large number of bands (CWE-1284), leading to excessive memory consumption (CWE-789) or an integer overflow (CWE-190).

  • CVE-2008-1440

    lack of validation of length field leads to infinite loop

  • CVE-2008-2374

    lack of validation of string length fields allows memory consumption or buffer over-read

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    This example demonstrates a shopping interaction in which the user is free to specify the quantity of items to be purchased and a total is calculated.

  2. 2

    The user has no control over the price variable, however the code does not prevent a negative value from being specified for quantity. If an attacker were to provide a negative value, then the user would have their account credited instead of debited.

  3. 3

    This example asks the user for a height and width of an m X n game board with a maximum dimension of 100 squares.

  4. 4

    While this code checks to make sure the user cannot specify large, positive integers and consume too much memory, it does not check for negative values supplied by the user. As a result, an attacker can perform a resource consumption (CWE-400) attack against this program by specifying two, large negative values that will not overflow, resulting in a very large memory allocation (CWE-789) and possibly a system crash. Alternatively, an attacker can provide very large negative values which will cause an integer overflow (CWE-190) and unexpected behavior will follow depending on how the values are treated in the remainder of the program.

Ejemplo de código vulnerable

Vulnerable Java

This example demonstrates a shopping interaction in which the user is free to specify the quantity of items to be purchased and a total is calculated.

Vulnerable Java 
...
  public static final double price = 20.00;
  int quantity = currentUser.getAttribute("quantity");
  double total = price * quantity;
  chargeUser(total);
  ...
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-1284

  • Implementation Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
Señales de detección

How to detect CWE-1284

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-1284 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-1284?

This vulnerability occurs when an application accepts user input meant to define a quantity—like a number, size, or count—but fails to properly check if that value is safe and reasonable before using it.

¿Qué gravedad tiene CWE-1284?

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-1284?

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

¿Cómo puedo prevenir CWE-1284?

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and…

¿Cómo detecta y corrige Plexicus CWE-1284?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-1284 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-1284?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/1284.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-1284

CWE-20 Padre

Improper Input Validation

This vulnerability occurs when an application accepts data from an external source but fails to properly verify that the data is safe and…

CWE-102 Hermano

Struts: Duplicate Validation Forms

This vulnerability occurs when an application defines multiple Struts validation forms with identical names. The framework then…

CWE-103 Hermano

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…

CWE-104 Hermano

Struts: Form Bean Does Not Extend Validation Class

This vulnerability occurs in Apache Struts applications when a form bean class does not properly extend the framework's validation class.…

CWE-105 Hermano

Struts: Form Field Without Validator

This vulnerability occurs when a Struts application form contains an input field that lacks a corresponding validator, leaving it open to…

CWE-106 Hermano

Struts: Plug-in Framework not in Use

This weakness occurs when a Java application, particularly one using the Struts framework, does not implement a structured input…

CWE-107 Hermano

Struts: Unused Validation Form

This vulnerability occurs when a Struts application contains validation form definitions that are no longer linked to any active form or…

CWE-108 Hermano

Struts: Unvalidated Action Form

In Apache Struts, every Action Form that processes user input must have a corresponding validation form configured. Missing this…

CWE-109 Hermano

Struts: Validator Turned Off

This vulnerability occurs when an application built with Apache Struts intentionally disables its built-in validation framework. By…

Recursos

Further reading

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