My notes about Nginx...
- Introduction
- External Resources
- Helpers
- Shell aliases
- Debugging
- See the top 5 IP addresses in a web server log
- Analyse web server log and show only 2xx http codes
- Analyse web server log and show only 5xx http codes
- Get range of dates in a web server log
- Get line rates from web server log
- Trace network traffic for all Nginx processes
- List all files accessed by a Nginx
- Base rules
- Organising Nginx configuration
- Separate listen directives for 80 and 443
- Use
default_server
directive at the beginning - Use only one SSL config for specific listen directive
- Force all connections over TLS
- Use geo/map modules instead allow/deny
- Map all the things...
- Drop the same root inside location block
- Use debug mode for debugging
- Performance
- Hardening
- Run as an unprivileged user
- Disable unnecessary modules
- Protect sensitive resources
- Hide Nginx version number
- Hide Nginx server signature
- Hide upstream proxy headers
- Use only 4096-bit private keys
- Keep only TLS 1.2 (+ TLS 1.3)
- Use only strong ciphers
- Use more secure ECDH Curve
- Use strong Key Exchange
- Defend against the BEAST attack
- Disable compression (mitigation of CRIME attack)
- HTTP Strict Transport Security
- Reduce XSS risks (Content-Security-Policy)
- Control the behavior of the Referer header (Referrer-Policy)
- Provide clickjacking protection (X-Frame-Options)
- Prevent some categories of XSS attacks (X-XSS-Protection)
- Prevent Sniff Mimetype middleware (X-Content-Type-Options)
- Deny the use of browser features (Feature-Policy)
- Reject unsafe HTTP methods
- Control Buffer Overflow attacks
- Mitigating Slow HTTP DoS attack (Closing Slow Connections)
- Configuration examples
Before using the Nginx please read Beginner’s Guide.
Nginx (/ˌɛndʒɪnˈɛks/ EN-jin-EKS) is an HTTP and reverse proxy server, a mail proxy server, and a generic TCP/UDP proxy server, originally written by Igor Sysoev. For a long time, it has been running on many heavily loaded Russian sites including Yandex, Mail.Ru, VK, and Rambler.
To increase your knowledge, read Nginx Documentation.
General disclaimer
This is not an official handbook. Many of these rules refer to external resources. It is rather a quick collection of some rules used by me in production environments (not only).
Before you start remember about the two most important things:
Do not follow guides just to get 100% of something. Think about what you actually do at your server!
These guidelines provides recommendations for very restrictive setup.
SSL Report: blkcipher.info
Many of these recipes have been applied to the configuration of my private website. I finally got all 100%'s on my scores:
An example configuration is in this chapter.
Printable high-res hardening checklist
Hardening checklist based on this recipes (@ssllabs A+ 100%) - High-Res 5000x8200.
For
*.xcf
and
About Nginx
References
Cheatsheets
Performance & Hardening
Config generators
Static analyzers
Log analyzers
Performance analyzers
Benchmarking tools
Online tools
Other stuff
Shell aliases
alias ng.test='nginx -t -c /etc/nginx/nginx.conf' alias ng.stop='ng.test && systemctl stop nginx' alias ng.reload='ng.test && systemctl reload nginx' alias ng.restart='ng.test && systemctl restart nginx' alias ng.restart='ng.test && kill -HUP `cat /var/run/nginx.pid`'
Debugging
See the top 5 IP addresses in a web server log
cut -d ' ' -f1 /path/to/logfile | sort | uniq -c | sort -nr | head -5 | nl
Analyse web server log and show only 2xx http codes
tail -n 100 -f /path/to/logfile | grep "HTTP/[1-2].[0-1]\" [2]"
Analyse web server log and show only 5xx http codes
tail -n 100 -f /path/to/logfile | grep "HTTP/[1-2].[0-1]\" [5]"
Get range of dates in a web server log
# 1) awk '/'$(date -d "1 hours ago" "+%d\\/%b\\/%Y:%H:%M")'/,/'$(date "+%d\\/%b\\/%Y:%H:%M")'/ { print $0 }' /path/to/logfile # 2) awk '/05\/Feb\/2019:09:2.*/,/05\/Feb\/2019:09:5.*/' /path/to/logfile
Get line rates from web server log
tail -F /path/to/logfile | pv -N RAW -lc 1>/dev/null
Trace network traffic for all Nginx processes
strace -e trace=network -p `pidof nginx | sed -e 's/ /,/g'`
List all files accessed by a Nginx
strace -ff -e trace=file nginx 2>&1 | perl -ne 's/^[^"]+"(([^\\"]|\\[\\"nt])*)".*/$1/ && print'
🔰 Organising Nginx configuration
Rationale
When your configuration grow, the need for organising your code will also grow. Well organised code is:
- easier to understand
- easier to maintain
- easier to work with
Use
include
directive to attach your Nginx specific code to global config, contexts and other.
Example
# Store this configuration in e.g. https-ssl-common.conf listen 10.240.20.2:443 ssl; root /etc/nginx/error-pages/other; ssl_certificate /etc/nginx/domain.com/certs/nginx_domain.com_bundle.crt; ssl_certificate_key /etc/nginx/domain.com/certs/domain.com.key; # And include this file in server section: server { include /etc/nginx/domain.com/commons/https-ssl-common.conf; server_name domain.com www.domain.com; ...
External resources
🔰 Separate listen directives for 80 and 443
Rationale
...
Example
# For http: server { listen 10.240.20.2:80; ... } # For https: server { listen 10.240.20.2:443 ssl; ... }
External resources
🔰 Use default_server
directive at the beginning
Rationale
If none of the directives have the
default_server
parameter then the first server with the address:port pair will be the default server for this pair.
Nginx should prevent processing requests with undefined server names - also traffic on ip address. It also protects against configuration errors and don't pass traffic to incorrect backends.
Example
server { listen 10.240.20.2:443 ssl; # Place it at the beginning of the configuration file. server_name default_server; ... location / { # serve static file (error page): root /etc/nginx/error-pages/404; # or redirect: # return 301 https://badssl.com; } } server { listen 10.240.20.2:443 ssl; server_name domain.com; ... } server { listen 10.240.20.2:443 ssl; server_name app.domain.com; ... }
External resources
🔰 Use only one SSL config for specific listen directive
Rationale
For sharing a single IP address between several HTTPS servers you should use one SSL config.
If you want to set up different SSL configurations for the same IP address then it will fail. It's important because SSL configuration is presented for default server name - if none of the directives have the
default_server
parameter then the first server in your configuration. So you should use only one SSL setup with several names on the same IP address.
Example
# Store this configuration in e.g. https.conf listen 192.168.252.10:443 ssl http2; ssl_protocols TLSv1.2; ssl_ciphers "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384"; ssl_prefer_server_ciphers on; ssl_ecdh_curve secp521r1:secp384r1; ... # Include this file to the server context (attach domain-a.com for specific listen directive) server { include /etc/nginx/https.conf; server_name domain-a.com; ... } # Include this file to the server context (attach domain-b.com for specific listen directive) server { include /etc/nginx/https.conf; server_name domain-b.com; ... }
External resources
🔰 Force all connections over TLS
Rationale
You should always use HTTPS instead of HTTP to protect your website, even if it doesn’t handle sensitive communications.
Example
server { listen 10.240.20.2:80; server_name domain.com; return 301 https://$host$request_uri; } server { listen 10.240.20.2:443 ssl; server_name domain.com; ... }
External resources
🔰 Use geo/map modules instead allow/deny
Rationale
Creates variables with values depending on the client IP address. Use map or geo modules (one of them) to prevent users abusing your servers.
Example
# Map module: map $remote_addr $globals_internal_map_acl { # Status code: # - 0 = false # - 1 = true default 0; ### INTERNAL ### 10.255.10.0/24 1; 10.255.20.0/24 1; 10.255.30.0/24 1; 192.168.0.0/16 1; } # Geo module: geo $globals_internal_geo_acl { # Status code: # - 0 = false # - 1 = true default 0; ### INTERNAL ### 10.255.10.0/24 1; 10.255.20.0/24 1; 10.255.30.0/24 1; 192.168.0.0/16 1; }
External resources
🔰 Map all the things...
Rationale
Map module provides a more elegant solution for clearly parsing a big list of regexes, e.g. User-Agents. Manage a large number of redirects with Nginx maps.
Example
map $http_user_agent $device_redirect { default "desktop"; ~(?i)ip(hone|od) "mobile"; ~(?i)android.*(mobile|mini) "mobile"; ~Mobile.+Firefox "mobile"; ~^HTC "mobile"; ~Fennec "mobile"; ~IEMobile "mobile"; ~BB10 "mobile"; ~SymbianOS.*AppleWebKit "mobile"; ~Opera\sMobi "mobile"; } if ($device_redirect = "mobile") { return 301 https://m.domain.com$request_uri; }
External resources
🔰 Drop the same root inside location block
Rationale
If you add a root to every location block then a location block that isn’t matched will have no root. Set global
root
inside server directive.
Example
server { server_name domain.com; root /var/www/domain.com/public; location / { ... } location /api { ... } location /static { root /var/www/domain.com/static; ... } }
External resources
🔰 Use debug mode for debugging
Rationale
There's probably more detail than you want, but that can sometimes be a lifesaver (but log file growing rapidly).
Example
rewrite_log on; error_log /var/log/nginx/error-debug.log debug;
External resources
🔰 Set manually worker processes
Rationale
The
worker_processes
directive is the sturdy spine of life for Nginx. This directive is responsible for letting our virtual server know many workers to spawn once it has become bound to the proper IP and port(s).
Official Nginx documentation say:
When one is in doubt, setting it to the number of available CPU cores would be a good start (the value "auto" will try to autodetect it).
I think for high load proxy servers (also standalone servers) the best value is
ALL_CORES - 1
(please test it before used).
Example
# VCPU = 4 , expr $(nproc --all) - 1 worker_processes 3;
External resources
🔰 Use HTTP/2
Rationale
HTTP/2 will make our applications faster, simpler, and more robust.
The primary goals for HTTP/2 are to reduce latency by enabling full request and response multiplexing, minimize protocol overhead via efficient compression of HTTP header fields, and add support for request prioritization and server push.
HTTP/2 is backwards-compatible with HTTP/1.1, so it would be possible to ignore it completely and everything will continue to work as before.
Example
# For https: server { listen 10.240.20.2:443 ssl http2; ...
External resources
- Introduction to HTTP/2
- What is HTTP/2 - The Ultimate Guide
- The HTTP/2 Protocol: Its Pros & Cons and How to Start Using It
🔰 Maintaining SSL Sessions
Rationale
This improves performance from the clients’ perspective, because it eliminates the need for a new (and time-consuming) SSL handshake to be conducted each time a request is made.
Most servers do not purge sessions or ticket keys, thus increasing the risk that a server compromise would leak data from previous (and future) connections.
Example
ssl_session_cache shared:SSL:10m; ssl_session_timeout 24h; ssl_session_tickets off; ssl_buffer_size 1400;
External resources
🔰 Run as an unprivileged user
Rationale
There is no real difference in security just by changing the process owner name. On the other hand in security, the principle of least privilege states that an entity should be given no more permission than necessary to accomplish its goals within a given system. This way only master process runs as root.
Example
# Edit nginx.conf: user www-data; # Set owner and group for root (app, default) directory: chown -R www-data:www-data /var/www/domain.com
External resources
🔰 Disable unnecessary modules
Rationale
It is recommended to disable any modules which are not required as this will minimize the risk of any potential attacks by limiting the operations allowed by the web server.
Example
# During installation: ./configure --without-http_autoindex_module # Comment modules in the configuration file e.g. modules.conf: # load_module /usr/share/nginx/modules/ndk_http_module.so; # load_module /usr/share/nginx/modules/ngx_http_auth_pam_module.so; # load_module /usr/share/nginx/modules/ngx_http_cache_purge_module.so; # load_module /usr/share/nginx/modules/ngx_http_dav_ext_module.so; load_module /usr/share/nginx/modules/ngx_http_echo_module.so; # load_module /usr/share/nginx/modules/ngx_http_fancyindex_module.so; load_module /usr/share/nginx/modules/ngx_http_geoip_module.so; load_module /usr/share/nginx/modules/ngx_http_headers_more_filter_module.so; # load_module /usr/share/nginx/modules/ngx_http_image_filter_module.so; # load_module /usr/share/nginx/modules/ngx_http_lua_module.so; load_module /usr/share/nginx/modules/ngx_http_perl_module.so; # load_module /usr/share/nginx/modules/ngx_mail_module.so; # load_module /usr/share/nginx/modules/ngx_nchan_module.so; # load_module /usr/share/nginx/modules/ngx_stream_module.so;
External resources
🔰 Protect sensitive resources
Rationale
Hidden directories and files should never be web accessible.
Example
if ($request_uri ~ "/\.git") { return 403; } # or location ~ /\.git { deny all; } # or location ~* ^.*(\.(?:git|svn|htaccess))$ { return 403; } # or all . directories/files in general (but remember about .well-known path) location ~ /\. { deny all; }
External resources
🔰 Hide Nginx version number
Rationale
Disclosing the version of Nginx running can be undesirable, particularly in environments sensitive to information disclosure.
Example
External resources
🔰 Hide Nginx server signature
Rationale
You should compile Nginx from sources with
ngx_headers_more
to usedmore_set_headers
directive.
Example
more_set_headers "Server: Unknown";
External resources
🔰 Hide upstream proxy headers
Rationale
When Nginx is used to proxy requests to an upstream server (such as a PHP-FPM instance), it can be beneficial to hide certain headers sent in the upstream response (for example, the version of PHP running).
Example
proxy_hide_header X-Powered-By; proxy_hide_header X-AspNetMvc-Version; proxy_hide_header X-AspNet-Version; proxy_hide_header X-Drupal-Cache;
External resources
🔰 Use only 4096-bit private keys
Rationale
Advisories recommend 2048 for now. Security experts are projecting that 2048 bits will be sufficient for commercial use until around the year 2030.
Generally there is no compelling reason to choose 4096 bit keys over 2048 provided you use sane expiration intervals.
If you want to get A+ with 100%s on SSL Lab you should definitely use 4096 bit private key.
I always generate 4096 bit keys for low busy sites since the downside is minimal (slightly lower performance) and security is slightly higher (although not as high as one would like).
Use of alternative solution: ECC Certificate Signing Request (CSR).
The "SSL/TLS Deployment Best Practices" book say:
The cryptographic handshake, which is used to establish secure connections, is an operation whose cost is highly influenced by private key size. Using a key that is too short is insecure, but using a key that is too long will result in “too much” security and slow operation. For most web sites, using RSA keys stronger than 2048 bits and ECDSA keys stronger than 256 bits is a waste of CPU power and might impair user experience. Similarly, there is little benefit to increasing the strength of the ephemeral key exchange beyond 2048 bits for DHE and 256 bits for ECDHE.
Konstantin Ryabitsev (Reddit):
Generally speaking, if we ever find ourselves in a world where 2048-bit keys are no longer good enough, it won't be because of improvements in brute-force capabilities of current computers, but because RSA will be made obsolete as a technology due to revolutionary computing advances. If that ever happens, 3072 or 4096 bits won't make much of a difference anyway. This is why anything above 2048 bits is generally regarded as a sort of feel-good hedging theatre.
Example
### Example (RSA): ( _fd="domain.com.key" ; _len="4096" ; openssl genrsa -out ${_fd} ${_len} ) # Let's Encrypt: certbot certonly -d domain.com -d www.domain.com --rsa-key-size 4096 ### Example (ECC): # _curve: prime256v1, secp521r1, secp384r1 ( _fd="domain.com.key" ; _fd_csr="domain.com.csr" ; _curve="prime256v1" ; \ openssl ecparam -out ${_fd} -name ${_curve} -genkey ; openssl req -new -key ${_fd} -out ${_fd_csr} -sha256 ) # Let's Encrypt (from above): certbot --csr ${_fd_csr} -[other-args]
For x25519
:
( _fd="private.key" ; _curve="x25519" ; \ openssl genpkey -algorithm ${_curve} -out ${_fd} )
ssllabs score: 100
( _fd="domain.com.key" ; _len="2048" ; openssl genrsa -out ${_fd} ${_len} ) # Let's Encrypt: certbot certonly -d domain.com -d www.domain.com
ssllabs score: 90
External resources
🔰 Keep only TLS 1.2 (+ TLS 1.3)
Rationale
It is recommended to run TLS 1.1/1.2 and fully disable SSLv2, SSLv3 and TLS 1.0 that have protocol weaknesses.
TLS 1.1 and 1.2 are both without security issues - but only v1.2 provides modern cryptographic algorithms. TLS 1.0 and TLS 1.1 protocols will be removed from browsers at the beginning of 2020.
Example
ssllabs score: 100
ssl_protocols TLSv1.2 TLSv1.1;
ssllabs score: 95
External resources
- TLS/SSL Explained – Examples of a TLS Vulnerability and Attack, Final Part
- Deprecating TLS 1.0 and 1.1 - Enhancing Security for Everyone
- TLS1.3 - OpenSSLWiki
- How to enable TLS 1.3 on Nginx
🔰 Use only strong ciphers
Rationale
This parameter changes quite often, the recommended configuration for today may be out of date tomorrow.
For more security use only strong and not vulnerable ciphersuite (but if you use http/2 you can get
Server sent fatal alert: handshake_failure
error).
Place
ECDHE
andDHE
suites at the top of your list. The order is important; because ECDHE suites are faster, you want to use them whenever clients supports them.
For backward compatibility software components you should use less restrictive ciphers.
You should definitely disable weak ciphers like those with DSS, DSA, DES/3DES, RC4, MD5, SHA1, null, anon in the name.
Example
ssl_ciphers "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384";
ssllabs score: 100
# 1) ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA:ECDHE-ECDSA-AES128-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256"; # 2) ssl_ciphers "ECDHE-ECDSA-CHACHA20-POLY1305:ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:!AES256-GCM-SHA256:!AES256-GCM-SHA128:!aNULL:!MD5";
ssllabs score: 90
External resources
- SSL/TLS: How to choose your cipher suite
- HTTP/2 and ECDSA Cipher Suites
- Which SSL/TLS Protocol Versions and Cipher Suites Should I Use?
- Why use Ephemeral Diffie-Hellman
🔰 Use more secure ECDH Curve
Rationale
x25519
is a more secure but slightly less compatible option. To maximise interoperability with existing browsers and servers, stick toP-256 prime256v1
andP-384 secp384r1
curves.
If you do not set
ssh_ecdh_curve
, then the Nginx will use its default settings, e.g. chrome will preferx25519
, but this is not recommended because you can not control the Nginx's default settings (seems to beP-256
).
Explicitly set
ssh_ecdh_curve X25519:prime256v1:secp521r1:secp384r1;
decreases the Key Exchange SSL Labs rating. On the other hand it's good solution because if web browser supportx25519
curves -> usex25519
otherwise try the next curve listed.
Do not use the
secp112r1
,secp112r2
,secp128r1
,secp128r2
,secp160k1
,secp160r1
,secp160r2
,secp192k1
curves. They have a too small size for security application according to NIST recommendation.
Example
ssl_ecdh_curve secp521r1:secp384r1;
ssllabs score: 100
# Alternative (this one doesn’t affect compatibility, by the way; it’s just a question of the preferred order) but downgrade Key Exchange score: ssl_ecdh_curve X25519:prime256v1:secp521r1:secp384r1;
External resources
- Standards for Efficient Cryptography Group
- SafeCurves: choosing safe curves for elliptic-curve cryptography
- P-521 is pretty nice prime
- Safe ECC curves for HTTPS are coming sooner than you think
- Cryptographic Key Length Recommendations
- Testing for Weak SSL/TLS Ciphers, Insufficient Transport Layer Protection (OTG-CRYPST-001)
- Elliptic Curve performance: NIST vs Brainpool
🔰 Use strong Key Exchange
Rationale
The DH key is only used if DH ciphers are used. Modern clients prefer ECDHE instead and if your Nginx accepts this preference then the handshake will not use the DH param at all since it will not do a DHE key exchange but an ECDHE key exchange.
Most of the "modern" profiles from places like Mozilla's ssl config generator no longer recommend using this.
Default key size in OpenSSL is
1024 bits
- it's vulnerable and breakable. For the best security configuration use your own4096 bit
DH Group or use known safe ones pre-defined DH groups (it's recommended) from mozilla.
Example
# To generate a DH key: openssl dhparam -out /etc/nginx/ssl/dhparam_4096.pem 4096 # To produce "DSA-like" DH parameters: openssl dhparam -dsaparam -out /etc/nginx/ssl/dhparam_4096.pem 4096 # To generate a ECDH key: openssl ecparam -out /etc/nginx/ssl/ecparam.pem -name prime256v1 # Nginx configuration: ssl_dhparam /etc/nginx/ssl/dhparams_4096.pem;
ssllabs score: 100
External resources
- Weak Diffie-Hellman and the Logjam Attack
- Pre-defined DHE groups
- Instructs OpenSSL to produce "DSA-like" DH parameters
- OpenSSL generate different types of self signed certificate
🔰 Defend against the BEAST attack
Rationale
Enables server-side protection from BEAST attacks.
Example
ssl_prefer_server_ciphers on;
External resources
🔰 Disable compression (mitigation of CRIME attack)
Rationale
Disabling SSL/TLS compression stops the attack very effectively.
Some attacks are possible because of gzip being enabled on SSL requests. In most cases, the best action is to simply disable gzip for SSL requests.
Example
External resources
🔰 HTTP Strict Transport Security
Rationale
The header indicates for how long a browser should unconditionally refuse to take part in unsecured HTTP connection for a specific domain.
Example
add_header Strict-Transport-Security "max-age=63072000; includeSubdomains" always;
ssllabs score: A+
External resources
🔰 Reduce XSS risks (Content-Security-Policy)
Rationale
CSP reduce the risk and impact of XSS attacks in modern browsers.
Example
# This policy allows images, scripts, AJAX, and CSS from the same origin, and does not allow any other resources to load. add_header Content-Security-Policy "default-src 'none'; script-src 'self'; connect-src 'self'; img-src 'self'; style-src 'self';" always;
External resources
🔰 Control the behavior of the Referer header (Referrer-Policy)
Rationale
Determine what information is sent along with the requests.
Example
add_header Referrer-Policy "no-referrer";
External resources
🔰 Provide clickjacking protection (X-Frame-Options)
Rationale
Helps to protect your visitors against clickjacking attacks. It is recommended that you use the
x-frame-options
header on pages which should not be allowed to render a page in a frame.
Example
add_header X-Frame-Options "SAMEORIGIN" always;
External resources
🔰 Prevent some categories of XSS attacks (X-XSS-Protection)
Rationale
Enable the cross-site scripting (XSS) filter built into modern web browsers.
Example
add_header X-XSS-Protection "1; mode=block" always;
External resources
🔰 Prevent Sniff Mimetype middleware (X-Content-Type-Options)
Rationale
It prevents the browser from doing MIME-type sniffing (prevents "mime" based attacks).
Example
add_header X-Content-Type-Options "nosniff" always;
External resources
🔰 Deny the use of browser features (Feature-Policy)
Rationale
This header protect your site from third parties using APIs that have security and privacy implications, and also from your own team adding outdated APIs or poorly optimized images.
Example
add_header Feature-Policy "geolocation none; midi none; notifications none; push none; sync-xhr none; microphone none; camera none; magnetometer none; gyroscope none; speaker none; vibrate none; fullscreen self; payment none; usb none;";
External resources
🔰 Reject unsafe HTTP methods
Rationale
Set of methods support by a resource. An ordinary web server supports the
HEAD
,GET
andPOST
methods to retrieve static and dynamic content. Other (e.g.OPTIONS
,TRACE
) methods should not be supported on public web servers, as they increase the attack surface.
Example
add_header Allow "GET, POST, HEAD" always; if ($request_method !~ ^(GET|POST|HEAD)$) { return 405; }
External resources
🔰 Control Buffer Overflow attacks
Rationale
Buffer overflow attacks are made possible by writing data to a buffer and exceeding that buffers’ boundary and overwriting memory fragments of a process. To prevent this in Nginx we can set buffer size limitations for all clients.
Example
client_body_buffer_size 100k; client_header_buffer_size 1k; client_max_body_size 100k; large_client_header_buffers 2 1k;
External resources
🔰 Mitigating Slow HTTP DoS attack (Closing Slow Connections)
Rationale
Close connections that are writing data too infrequently, which can represent an attempt to keep connections open as long as possible.
Example
client_body_timeout 10s; client_header_timeout 10s; keepalive_timeout 5s 5s; send_timeout 10s;
External resources
Remember to make a copy of the current configuration and all files/directories.
Nginx Contexts
Before read this configuration remember about Nginx Contexts structure:
Core Contexts
Global/Main Context
Events Context
HTTP Context
Server Context
Location Context
Upstream Context
Mail Context
Reverse Proxy
This chapter describes the basic configuration of my proxy server (for blkcipher.info domain).
Import configuration
It's very simple - clone the repo and perform full directory sync:
git clone https://github.com/trimstray/nginx-quick-reference.git rsync -avur --delete lib/nginx/ /etc/nginx/
For leaving your configuration (not recommended) remove
--delete
rsync param.
Set bind IP address
Find and replace 192.168.252.2 string in directory and file names
cd /etc/nginx find . -depth -name '*192.168.252.2*' -execdir bash -c 'mv -v "$1" "${1//192.168.252.2/xxx.xxx.xxx.xxx}"' _ {} \;
Find and replace 192.168.252.2 string in configuration files
cd /etc/nginx find . -type f -print0 | xargs -0 sed -i 's/192.168.252.2/xxx.xxx.xxx.xxx/g'
Set your domain name
Find and replace blkcipher.info string in directory and file names
cd /etc/nginx find . -depth -name '*blkcipher.info*' -execdir bash -c 'mv -v "$1" "${1//blkcipher.info/example.com}"' _ {} \;
Find and replace blkcipher.info string in configuration files
cd /etc/nginx find . -type f -print0 | xargs -0 sed -i 's/blkcipher_info/example_com/g' find . -type f -print0 | xargs -0 sed -i 's/blkcipher.info/example.com/g'
Regenerate private keys and certs
For localhost
cd /etc/nginx/master/_server/localhost/certs # Private key + Self-signed certificate ( _fd="localhost.key" ; _fd_crt="nginx_localhost_bundle.crt" ; \ openssl req -x509 -newkey rsa:4096 -keyout ${_fd} -out ${_fd_crt} -days 365 -nodes \ -subj "/C=X0/ST=localhost/L=localhost/O=localhost/OU=X00/CN=localhost" )
For default_server
cd /etc/nginx/master/_server/defaults/certs # Private key + Self-signed certificate ( _fd="defaults.key" ; _fd_crt="nginx_defaults_bundle.crt" ; \ openssl req -x509 -newkey rsa:4096 -keyout ${_fd} -out ${_fd_crt} -days 365 -nodes \ -subj "/C=X1/ST=default/L=default/O=default/OU=X11/CN=default_server" )
For your domain (e.g. Let's Encrypt)
cd /etc/nginx/master/_server/example.com/certs # For multidomain: certbot certonly -d example.com -d www.example.com --rsa-key-size 4096 # For wildcard: certbot certonly --manual --preferred-challenges=dns -d example.com -d *.example.com --rsa-key-size 4096 # Copy private key and chain: cp /etc/letsencrypt/live/example.com/fullchain.pem nginx_example.com_bundle.crt cp /etc/letsencrypt/live/example.com/privkey.pem example.com.key
Add new domain
Updated nginx.conf
# At the end of the file (in 'IPS/DOMAINS' section) include /etc/nginx/master/_server/domain.com/servers.conf; include /etc/nginx/master/_server/domain.com/backends.conf;
Init domain directory
cd /etc/nginx/cd master/_server cp -R example.com domain.com cd domain.com find . -depth -name '*example.com*' -execdir bash -c 'mv -v "$1" "${1//example.com/domain.com}"' _ {} \; find . -type f -print0 | xargs -0 sed -i 's/example_com/domain_com/g' find . -type f -print0 | xargs -0 sed -i 's/example.com/domain.com/g'
Test your configuration
nginx -t -c /etc/nginx/nginx.conf