Basic Nginx configuration

Often during a penetration test, phishing awareness campaign, or red team, I need to set up a webserver to host payloads, phishing websites, etc. This short post is a collection of Nginx configuration directives that I commonly use.
Example use cases: redirect HTTP traffic to HTTPS, enable PHP processing, configure a reverse proxy for HTTP(s) or TCP/UDP streams, add or remove HTTP headers in the responses or adding them for upstream servers.

Redirect HTTP traffic to HTTPS

server {
  listen 80;

  return 301 https://$host$request_uri;
}

Enable PHP

Enable PHP file processing on SSL website, with php-fpm:

server {
  listen 8443 ssl default_server;
  server_name _;

  ssl_certificate /etc/letsencrypt/live/DOMAIN-NAME/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/DOMAIN-NAME/privkey.pem;

  root /var/www/html;

  index index.html index.htm index.php;

  location / {
    try_files $uri $uri/ =404;
  }

  location ~ \.php$ {
         include snippets/fastcgi-php.conf;
  
         fastcgi_pass unix:/run/php/php7.4-fpm.sock;
  }
}

Streams

Forward TCP port 443 to target-host:8443:

Note: stream must be on the same level as http - put such entry in nginx.conf file, not in VHOST configuration files.

stream {
  server {
    listen 443;
    proxy_pass target-host:8443;
  }
}

Redirect all DNS traffic:

stream {
  server {
    listen 53 udp;
    proxy_pass 10.0.0.1:53;
  }
}

Basic nginx.conf with stream:

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
	worker_connections 768;
}

http {
	sendfile on;
	tcp_nopush on;
	tcp_nodelay on;
	keepalive_timeout 65;
	types_hash_max_size 2048;

	include /etc/nginx/mime.types;
	default_type application/octet-stream;

	ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
	ssl_prefer_server_ciphers on;

	access_log /var/log/nginx/access.log;
	error_log /var/log/nginx/error.log;

	gzip on;

	include /etc/nginx/conf.d/*.conf;
	include /etc/nginx/sites-enabled/*;
}

stream {
  server {
    listen 443;
    proxy_pass target-host:8443;
  }
}

Adding or removing headers

Hide X-Server header example:

location / {
  proxy_pass http://127.0.0.1:8888/;

  proxy_hide_header X-Server;
}

Add X-Frame-Options header:

location / {
  proxy_pass http://127.0.0.1:8888/;

  add_header X-Frame-Options SAMEORIGIN;
}

Adding headers to proxy upstream

location / {
    proxy_pass http://127.0.0.1:8888/;

    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Host $host;
    proxy_set_header X-Real-IP $remote_addr;
}

2020-09-14

#nginx