CWE-64 Variante Incompleto Low likelihood

Windows Shortcut Following (.LNK)

This vulnerability occurs when an application opens a file or directory without properly validating that it is a Windows shortcut (.LNK). If the shortcut's target points to a location outside the…

Definición

What is CWE-64?

This vulnerability occurs when an application opens a file or directory without properly validating that it is a Windows shortcut (.LNK). If the shortcut's target points to a location outside the application's intended security boundary, an attacker can trick the software into accessing unauthorized files.
Windows shortcut files (.LNK) contain a reference to a target file or folder, but they are separate objects with their own permissions. An application that fails to resolve the shortcut's final destination before performing operations can be manipulated. An attacker can place a malicious .LNK file in a location the application trusts, but configure it to point to a sensitive system file or a directory they shouldn't have access to, effectively bypassing intended access controls. This allows for unauthorized file reads or writes. For example, an application designed to process user-uploaded files in a sandboxed folder could be tricked into reading the Windows SAM database or overwriting a critical configuration file because it blindly follows the shortcut. The core security failure is not canonicalizing the path to the shortcut's true target and checking if that resolved path is within the allowed scope before proceeding.
Impacto en el mundo real

Real-world CVEs caused by CWE-64

  • CVE-2019-19793

    network access control service executes program with high privileges and allows symlink to invoke another executable or perform DLL injection.

  • CVE-2000-0342

    Mail client allows remote attackers to bypass the user warning for executable attachments such as .exe, .com, and .bat by using a .lnk file that refers to the attachment, aka "Stealth Attachment."

  • CVE-2001-1042

    FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.

  • CVE-2001-1043

    FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.

  • CVE-2005-0587

    Browser allows remote malicious web sites to overwrite arbitrary files by tricking the user into downloading a .LNK (link) file twice, which overwrites the file that was referenced in the first .LNK file.

  • CVE-2001-1386

    ".LNK." - .LNK with trailing dot

  • CVE-2003-1233

    Rootkits can bypass file access restrictions to Windows kernel directories using NtCreateSymbolicLinkObject function to create symbolic link

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-64

  • Architecture and Design Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
Señales de detección

How to detect CWE-64

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-64 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-64?

This vulnerability occurs when an application opens a file or directory without properly validating that it is a Windows shortcut (.LNK). If the shortcut's target points to a location outside the application's intended security boundary, an attacker can trick the software into accessing unauthorized files.

¿Qué gravedad tiene CWE-64?

MITRE califica la probabilidad de explotación como Baja — la explotación es poco frecuente, pero la debilidad debe corregirse cuando se descubra.

¿Qué lenguajes o plataformas se ven afectados por CWE-64?

MITRE lists the following affected platforms: Windows.

¿Cómo puedo prevenir CWE-64?

Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

¿Cómo detecta y corrige Plexicus CWE-64?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-64 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-64?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/64.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-64

CWE-59 Padre

Improper Link Resolution Before File Access ('Link Following')

This vulnerability occurs when an application uses a filename to access a file but fails to properly check if that name points to a…

CWE-1386 Hermano

Insecure Operation on Windows Junction / Mount Point

This vulnerability occurs when a Windows application opens a file or directory without properly validating that the path is not a symbolic…

CWE-61 Hermano

UNIX Symbolic Link (Symlink) Following

This vulnerability occurs when a software application opens files or directories without properly checking if they are symbolic links…

CWE-62 Hermano

UNIX Hard Link

This vulnerability occurs when an application opens a file or directory without verifying if the name points to a hard link that leads…

CWE-65 Hermano

Windows Hard Link

This vulnerability occurs when a Windows application opens a file or directory without properly verifying if the path points to a hard…

Recursos

Further reading

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