bunkerized-nginx

nginx based Docker image secure by default.
Non-exhaustive list of features :

• HTTPS support with transparent Let's Encrypt automation
• State-of-the-art web security : HTTP security headers, php.ini hardening, prevent leaks, ...
• Integrated ModSecurity WAF with the OWASP Core Rule Set
• Automatic ban of strange behaviors with fail2ban
• Block TOR users, bad user-agents, countries, ...
• Detect bad files with ClamAV
• Based on alpine and compiled from source
• Easy to configure with environment variables

Table of contents

• bunkerized-nginx
• Table of contents
• Live demo
• Quickstart guide
  • Run HTTP server with default settings
  • Run HTTPS server with automated Let's Encrypt
  • Reverse proxy
• Tutorials
• List of environment variables
  • nginx
  • HTTPS
  • ModSecurity
  • Security headers
  • Blocking
  • PHP
  • Fail2ban
  • ClamAV
  • Misc
• Include custom configurations
• Create your own image
• TODO

Live demo

You can find a live demo at https://demo-nginx.bunkerity.com.

Quickstart guide

Run HTTP server with default settings

docker run -p 80:80 -v /path/to/web/files:/www bunkerity/bunkerized-nginx

Web files are stored in the /www directory, the container will serve files from there.

Run HTTPS server with automated Let's Encrypt

docker run -p 80:80 -p 443:443 -v /path/to/web/files:/www -v /where/to/save/certificates:/etc/letsencrypt -e SERVER_NAME=www.yourdomain.com -e AUTO_LETS_ENCRYPT=yes -e REDIRECT_HTTP_TO_HTTPS=yes bunkerity/bunkerized-nginx

Certificates are stored in the /etc/letsencrypt directory, you should save it on your local drive.
If you don't want your webserver to listen on HTTP add the environment variable LISTEN_HTTP with a "no" value. But Let's Encrypt needs the port 80 to be opened so redirecting the port is mandatory.

Here you have three environment variables :

• SERVER_NAME : define the FQDN of your webserver, this is mandatory for Let's Encrypt (www.yourdomain.com should point to your IP address)
• AUTO_LETS_ENCRYPT : enable automatic Let's Encrypt creation and renewal of certificates
• REDIRECT_HTTP_TO_HTTPS : enable HTTP to HTTPS redirection

Reverse proxy

You can setup a reverse proxy by adding your own custom configurations at server context.
For example, this is a dummy reverse proxy configuration :

location / {
	if ($host = www.website1.com) {
		proxy_pass http://192.168.42.10$request_uri;
	}

	if ($host = www.website2.com) {
		proxy_pass http://192.168.42.11$request_uri;
	}
}

All files (ending with .conf) in /server-confs inside the container will be included at server context. You can simply mount a volume where your config files are located :

docker run -p 80:80 -e SERVER_NAME="www.website1.com www.website2.com" -e SERVE_FILES=no -e DISABLE_DEFAULT_SERVER=yes -v /path/to/server/conf:/server-confs bunkerity/bunkerized-nginx

Here you have three environment variables :

• SERVER_NAME : list of valid Host headers sent by clients
• SERVE_FILES : nginx will not serve files from the /www directory
• DISABLE_DEFAULT_SERVER : nginx will not respond to requests if Host header is not in the SERVER_NAME list

Tutorials

You will find some tutorials about bunkerized-nginx in our blog.

List of environment variables

nginx

SERVER_TOKENS
Values : on | off
Default value : off
If set to on, nginx will display server version in Server header and default error pages.

HEADER_SERVER
Values : yes | no
Default value : no
If set to no, nginx will remove the Server header in HTTP responses.

ALLOWED_METHODS
Values : allowed HTTP methods separated with | char
Default value : GET|POST|HEAD
Only the HTTP methods listed here will be accepted by nginx. If not listed, nginx will close the connection.

DISABLE_DEFAULT_SERVER
Values : yes | no
Default value : no
If set to yes, nginx will only respond to HTTP request when the Host header match a FQDN specified in the SERVER_NAME environment variable.
For example, it will close the connection if a bot access the site with direct ip.

SERVE_FILES
Values : yes | no
Default value : yes
If set to yes, nginx will serve files from /www directory within the container.
A use case to not serving files is when you setup bunkerized-nginx as a reverse proxy via a custom configuration.

ROOT_FOLDER
Values : *<any valid path to web files>
Default value : /www
The default folder where nginx will search for web files. Don't change it unless you want to make your own image (TODO).

MAX_CLIENT_SIZE
Values : 0 | Xm
Default value : 10m
Sets the maximum body size before nginx returns a 413 error code.
Setting to 0 means "infinite" body size.

SERVER_NAME
Values : <first name> <second name> ...
Default value : www.bunkerity.com
Sets the host names of the webserver separated with spaces. This must match the Host header sent by clients.
Useful when used with AUTO_LETSENCRYPT=yes and/or DISABLE_DEFAULT_SERVER=yes.

WRITE_ACCESS
Values : yes | no
Default value : no
If set to yes, nginx will be granted write access to the /www directory.
Set it to yes if your website uses file upload or creates dynamic files for example.

USE_AUTH_BASIC
Values : yes | no
Default value : no
If set to yes, enables HTTP basic authentication at the location AUTH_BASIC_LOCATION with user AUTH_BASIC_USER and password AUTH_BASIC_PASSWORD.

AUTH_BASIC_LOCATION
Values : / | /subdir/ | <any valid location>
Default value : /
The location to restrict when USE_AUTH_BASIC is set to yes. By default, all the website is restricted (/).

AUTH_BASIC_USER
Values : <any valid username>
Default value : changeme
The username allowed to access AUTH_BASIC_LOCATION when USE_AUTH_BASIC is set to yes.

AUTH_BASIC_PASSWORD
Values : <any valid password>
Default value : changeme
The password of AUTH_BASIC_USER when USE_AUTH_BASIC is set to yes.

AUTH_BASIC_TEXT
Values : <any valid text>
Default value : Restricted area
The text displayed inside the login prompt when USE_AUTH_BASIC is set to yes.

HTTPS

AUTO_LETS_ENCRYPT
Values : yes | no
Default value : no
If set to yes, automatic certificate generation and renewal will be setup through Let's Encrypt. This will enable HTTPS on your website for free.
You will need to redirect both 80 and 443 port to your container and also set the SERVER_NAME environment variable.

LISTEN_HTTP
Values : yes | no
Default value : yes
If set to no, nginx will not in listen on HTTP (port 80).
Useful if you only want HTTPS access to your website.

REDIRECT_HTTP_TO_HTTPS
Values : yes | no
Default value : no
If set to yes, nginx will redirect all HTTP requests to HTTPS.

HTTP2
Values : yes | no
Default value : yes
If set to yes, nginx will use HTTP2 protocol when HTTPS is enabled.

USE_CUSTOM_HTTPS Values : yes | no
Default value : no
If set to yes, HTTPS will be enabled with certificate/key of your choice.

CUSTOM_HTTPS_CERT
Values : <any valid path inside the container>
Default value :
Full path of the certificate file to use when USE_CUSTOM_HTTPS is set to yes.

CUSTOM_HTTPS_KEY
Values : <any valid path inside the container>
Default value :
Full path of the key file to use when USE_CUSTOM_HTTPS is set to yes.

ModSecurity

USE_MODSECURITY
Values : yes | no
Default value : yes
If set to yes, the ModSecurity WAF will be enabled.
You can include custom rules by adding .conf files into the /modsec-confs/ directory inside the container (i.e : through a volume).

USE_MODSECURITY_CRS
Values: yes | no Default value : yes If set to yes, the OWASP ModSecurity Core Rule Set will be used. It provides generic rules to detect common web attacks.
You can customize the CRS (i.e. : add WordPress exclusions) by adding custom .conf files into the /modsec-crs-confs/ directory inside the container (i.e : through a volume).

Security headers

X_FRAME_OPTIONS
Values : DENY | SAMEORIGIN | ALLOW-FROM https://www.website.net | ALLOWALL
Default value : DENY
Policy to be used when the site is displayed through iframe. Can be used to mitigate clickjacking attacks. More info here.

X_XSS_PROTECTION
Values : 0 | 1 | 1; mode=block
Default value : 1; mode=block
Policy to be used when XSS is detected by the browser. Only works with Internet Explorer.
More info here.

X_CONTENT_TYPE_OPTIONS
Values : nosniff
Default value : nosniff
Tells the browser to be strict about MIME type.
More info here.

REFERRER_POLICY
Values : no-referrer | no-referrer-when-downgrade | origin | origin-when-cross-origin | same-origin | strict-origin | strict-origin-when-cross-origin | unsafe-url
Default value : no-referrer
Policy to be used for the Referer header.
More info here.

FEATURE_POLICY
Values : <directive> <allow list>
Default value : accelerometer 'none'; ambient-light-sensor 'none'; autoplay 'none'; camera 'none'; display-capture 'none'; document-domain 'none'; encrypted-media 'none'; fullscreen 'none'; geolocation 'none'; gyroscope 'none'; magnetometer 'none'; microphone 'none'; midi 'none'; payment 'none'; picture-in-picture 'none'; speaker 'none'; sync-xhr 'none'; usb 'none'; vibrate 'none'; vr 'none'
Tells the browser which features can be used on the website.
More info here.

COOKIE_FLAGS
Values : * HttpOnly | MyCookie secure SameSite | ...
Default value : * HttpOnly
Adds some security to the cookies set by the server.
Accepted value can be found here.

STRICT_TRANSPORT_POLICY
Values : max-age=expireTime [; includeSubDomains] [; preload]
Default value : max-age=31536000
Tells the browser to use exclusively HTTPS instead of HTTP when communicating with the server.
More info here.

CONTENT_SECURITY_POLICY
Values : <directive 1>; <directive 2>; ...
Default value : default-src 'self'; frame-ancestors 'self'; form-action 'self'; block-all-mixed-content; sandbox allow-forms allow-same-origin allow-scripts; reflected-xss block; base-uri 'self'; referrer no-referrer
Policy to be used when loading resources (scripts, forms, frames, ...).
More info here.

Blocking

BLOCK_COUNTRY
Values : <country code 1> <country code 2> ...
Default value :
Block some countries from accessing your website. Use 2 letters country code separated with space.

BLOCK_USER_AGENT
Values : yes | no
Default value : yes If set to yes, block clients with "bad" user agent.
Blacklist can be found here.

BLOCK_TOR_EXIT_NODE
Values : yes | no
Default value : no
Is set to yes, will block TOR clients.

PHP

USE_PHP
Values : yes | no
Default value : yes
If set to yes, PHP files will be executed by the server.

PHP_DISPLAY_ERRORS
Values : yes | no
Default value : no
If set to yes, PHP errors will be shown to clients.

PHP_EXPOSE
Values : yes | no
Default value : no
If set to yes, the PHP version will be sent within the X-Powered-By header.

PHP_OPEN_BASEDIR
Values : <directories separated with : char>
Default value : /www/:/tmp/
Limits access to files within the given directories. For example include() or fopen() calls outside the directory will fail.

PHP_ALLOW_URL_FOPEN
Values : yes | no
Default value : no
If set to yes, allows using url in fopen() calls (i.e. : ftp://, http://, ...).

PHP_ALLOW_URL_INCLUDE
Values : yes | no
Default value : no
If set to yes, allows using url in include() calls (i.e. : ftp://, http://, ...).

PHP_FILE_UPLOADS
Values : yes | no
Default value : yes
If set to yes, allows clients to upload files.

PHP_UPLOAD_MAX_FILESIZE
Values : <size in bytes> | XM
Default value : 10M
Sets the maximum file size allowed when uploading files.

PHP_POST_MAX_SIZE
Values : <size in bytes> | XM
Default value : 10M
Sets the maximum POST size allowed for clients.

PHP_DISABLE_FUNCTIONS
Values : <function 1>, <function 2> ...
Default value : system, exec, shell_exec, passthru, phpinfo, show_source, highlight_file, popen, proc_open, fopen_with_path, dbmopen, dbase_open, putenv, filepro, filepro_rowcount, filepro_retrieve, posix_mkfifo
List of PHP functions blacklisted separated with commas. They can't be used anywhere in PHP code.

Fail2ban

USE_FAIL2BAN
Values : yes | no
Default value : yes
If set to yes, fail2ban will be used to block users getting too much "strange" HTTP codes in a period of time.
Instead of using iptables which is not possible inside a container, fail2ban will dynamically update nginx to ban/unban IP addresses.
If a number (FAIL2BAN_MAXRETRY) of "strange" HTTP codes (FAIL2BAN_STATUS_CODES) is found between a time interval (FAIL2BAN_FINDTIME) then the originating IP address will be ban for a specific period of time (FAIL2BAN_BANTIME).

FAIL2BAN_STATUS_CODES
Values : <HTTP status codes separated with | char>
Default value : 400|401|403|404|405|444
List of "strange" error codes that fail2ban will search for.

FAIL2BAN_BANTIME
Values :
Default value : 3600
The duration time, in seconds, of a ban.

FAIL2BAN_FINDTIME
Values :
Default : value : 60
The time interval, in seconds, to search for "strange" HTTP status codes.

FAIL2BAN_MAXRETRY
Values : <any positive integer>
Default : value : 20
The number of "strange" HTTP status codes to find between the time interval.

ClamAV

USE_CLAMAV_UPLOAD
Values : yes | no
Default value : yes
If set to yes, ClamAV will scan every file uploads and block the upload if the file is detected.

USE_CLAMAV_SCAN
Values : yes | no
Default value : yes
If set to yes, ClamAV will scan all the files inside the container every day.

CLAMAV_SCAN_REMOVE
Values : yes | no
Default value : yes
If set to yes, ClamAV will automatically remove the detected files.

Misc

ADDITIONAL_MODULES
Values : <list of packages separated with space>
Default value :
You can specify additional modules to install. All alpine packages are valid.
A use case is to use this to install PHP extensions (e.g. : php7-json php7-xml php7-curl ...).

Create your own image

You can use bunkerity/bunkerized-nginx as a base image for your web application.
Here is a Dockerfile example :

FROM bunkerity/bunkerized-nginx

# Copy your web files to a folder
COPY ./web-files/ /opt/web-files

# Optional : add your own script to be executed on startup
COPY ./my-entrypoint.sh /entrypoint.d/my-entrypoint.sh
RUN chmod +x /entrypoint.d/my-entrypoint.sh

# Mandatory variables to make things working
ENV ROOT_FOLDER /opt/web-files
ENV PHP_OPEN_BASEDIR /opt/web-files/:/tmp/

# Optional variables
ENV MAX_CLIENT_SIZE 100m
ENV PHP_UPLOAD_MAX_FILESIZE 100M
ENV WRITE_ACCESS yes
ENV ADDITIONAL_MODULES php7-mysqli php7-json php7-session

Include custom configurations

Custom configurations files (ending with .conf suffix) can be added in some directory inside the container :

• /http-confs : http context
• /server-confs : server context

You just need to use a volume like this :

docker run ... -v /path/to/http/confs:/http-confs ... bunkerity/bunkerized-nginx

TODO

• docker tags
• Tutorials
• Full documentation
• nginx compile flags
• Antibot with recaptcha v3
• HSTS preload, HPKP
• Web UI