CWE-293 Variante Borrador High likelihood

Using Referer Field for Authentication

This vulnerability occurs when a web application uses the HTTP Referer header as a sole or primary method for authentication or authorization decisions. Since this header is entirely controlled by…

Definición

What is CWE-293?

This vulnerability occurs when a web application uses the HTTP Referer header as a sole or primary method for authentication or authorization decisions. Since this header is entirely controlled by the user's browser or client and can be easily forged, it provides no reliable security.
The HTTP Referer header is designed to tell a server which page a user came from, but it was never intended for security. Treating it as a trusted credential is like using a 'recommended by a friend' note for building access—anyone can write it. Developers might implement this check to prevent cross-site request forgery (CSRF) or to restrict direct URL access, but because attackers can fully manipulate the header with simple tools like a proxy or browser extension, this defense is completely ineffective. To properly secure authentication and authorization, always use established server-side mechanisms like session tokens, CSRF tokens, or standard authentication protocols (OAuth, SAML). These methods rely on secrets or cryptographic signatures that the client cannot easily forge. Relying on the Referer header creates a false sense of security and leaves critical application functions exposed to trivial bypass attacks.
Impacto en el mundo real

Real-world CVEs caused by CWE-293

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 C++

The following code samples check a packet's referer in order to decide whether or not an inbound request is from a trusted host.

Vulnerable C++ 
String trustedReferer = "http://www.example.com/"
  while(true){
  	n = read(newsock, buffer, BUFSIZE);
  	requestPacket = processPacket(buffer, n);
  	if (requestPacket.referer == trustedReferer){
  		openNewSecureSession(requestPacket);
  	}
  }
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-293

  • Architecture and Design In order to usefully check if a given action is authorized, some means of strong authentication and method protection must be used. Use other means of authorization that cannot be simply spoofed. Possibilities include a username/password or certificate.
Señales de detección

How to detect CWE-293

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-293 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-293?

This vulnerability occurs when a web application uses the HTTP Referer header as a sole or primary method for authentication or authorization decisions. Since this header is entirely controlled by the user's browser or client and can be easily forged, it provides no reliable security.

¿Qué gravedad tiene CWE-293?

MITRE califica la probabilidad de explotación como Alta — esta debilidad se explota activamente en la práctica y debe priorizarse para su remediación.

¿Qué lenguajes o plataformas se ven afectados por CWE-293?

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

¿Cómo puedo prevenir CWE-293?

In order to usefully check if a given action is authorized, some means of strong authentication and method protection must be used. Use other means of authorization that cannot be simply spoofed. Possibilities include a username/password or certificate.

¿Cómo detecta y corrige Plexicus CWE-293?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-293 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-293?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/293.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-293

CWE-290 Padre

Authentication Bypass by Spoofing

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing…

CWE-291 Hermano

Reliance on IP Address for Authentication

This vulnerability occurs when a system uses a client's IP address as the sole or primary method to verify their identity.

CWE-350 Hermano

Reliance on Reverse DNS Resolution for a Security-Critical Action

This vulnerability occurs when an application uses a reverse DNS lookup on an IP address to get a hostname and then uses that hostname for…

Recursos

Further reading

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