Improve security and privacy in nginx config

- Use modern protocols (TLSv1.3 and HTTTP2)
- Enable browser XSS prevention
- Disable `Referrer` headers (prevent information leaks)
- Prohibit search engine crawling
- Disable access logs

server/files/etc/nginx/misp

@@ -1,26 +1,52 @@
 server {
     listen 80 default_server;
-    listen [::]:80;
+    listen [::]:80 default_server;
 
-    server_name _;
+    # Disable access logs
+    access_log off;
+    log_not_found off;
+    error_log  /var/log/nginx/error.log error;
 
     return 301 https://$host$request_uri;
 }
 
 server {
-
-    server_name misp-server;
-    listen 443 ssl http2 spdy;
+    listen 443 ssl http2;
+    listen [::]:443 ssl http2;
     root /var/www/MISP/app/webroot;
     index index.php;
 
+    # Disable access logs
+    access_log off;
+    log_not_found off;
+    error_log  /var/log/nginx/error.log error;
+
     ssl_certificate /etc/ssl/cert.pem;
     ssl_certificate_key /etc/ssl/key.pem;
+    ssl_session_timeout 1d;
+    ssl_session_cache shared:MozSSL:10m;  # about 40000 sessions
+    ssl_session_tickets off;
+    
+    # modern configuration
+    ssl_protocols TLSv1.3;
+    ssl_prefer_server_ciphers off;
 
     # enable HSTS
     add_header Strict-Transport-Security "max-age=15768000; includeSubdomains";
     add_header X-Frame-Options SAMEORIGIN;
 
+    # Aded headers for hardening browser security
+    add_header Referrer-Policy "no-referrer" always;                                                 
+    add_header X-Content-Type-Options "nosniff" always;                                              
+    add_header X-Download-Options "noopen" always;                                                   
+    add_header X-Frame-Options "SAMEORIGIN" always;                                                  
+    add_header X-Permitted-Cross-Domain-Policies "none" always;                                     
+    add_header X-Robots-Tag "none" always;                                                           
+    add_header X-XSS-Protection "1; mode=block" always;                                              
+                                                                                                     
+    # Remove X-Powered-By, which is an information leak
+    fastcgi_hide_header X-Powered-By;
+
     location / {
         try_files $uri $uri/ /index.php;
     }