Wednesday 12 February 2020

Secure Your Website htaccess Security Tips

Secure Your Website htaccess Security Tips

Secure Your Website htaccess Security Tips


If the website is hosted on an Apache server, there is a powerful mechanism available to help mitigating attacks: the Apache .htaccess file. Properly configured, the .htaccess file on a server with mod_rewrite enabled can provide a robust defense against many HTTP Request attacks.Apache web servers has a great way to manipulate information using .htaccess files. .htaccess (hypertext access) is the default name of a directory-level configuration file that allows for decentralized management of web server configuration. The .htaccess file is placed inside the web tree, and is able to override a subset of the server’s global configuration; the extent of this subset is defined by the web server administrator. The original purpose of .htaccess was to allow per-directory access control (e.g. requiring a password to access the content), hence the name. Nowadays .htaccess can override many other configuration settings, mostly related to content control, e.g. content type and character set, CGI handlers, etc. Following are few very useful htaccess tricks.

When you have a website, you need to deal with and protect yourself from common attacks such as Cross-Site Scripting, Local File Inclusion and SQL Injection which all start with transmission of hostile commands via the HTTP Request. The challenge consists of separating legitimate requests from the hostile or malicious ones.

1. Custom Directory Index Files

DirectoryIndex index.html index.php index.htm
You can change a default index file of directory by using above snippet in your htaccess file. If a user request /foo/, Apache will serve up /foo/index.html, or whatever file you specify.

2. Custom Error Pages

ErrorDocument 404 errors/404.html
You may want to redirect your users to an error page is any of the http errors like 404 occurs. You can use above snippet in htaccess file to map 404 error to error page errors/404.html. Also you may want to write a common page for all the http errors as follows: 
ErrorDocument 404 /psych/cgi-bin/error/error?404

3. Control access at files & directory level

.htaccess is most often used to restrict or deny access to individual files and folders. A typical example would be an “includes” folder. Your site’s pages can call these included scripts all they like, but you don’t want users accessing these files directly, over the web. In that case you would drop an .htaccess file in the includes folder with content something like this. 
# no one gets in here!
deny from all
which would deny ALL direct access to ANY files in that folder. You can be more specific with your conditions, for instance limiting access to a particular IP range, here’s a handy top-level rule for a local test server. 
# no nasty crackers in here!
order deny,allow
deny from all
allow from 192.168.0.0/24
# this would do the same thing..
#allow from 192.168.0
Generally these sorts of requests would bounce off your firewall anyway, but on a live server they become useful for filtering out undesirable IP blocks, known risks, lots of things. Sometimes, you will only want to ban one IP, perhaps some persistent robot that doesn’t play by the rules. 
# someone else giving the ruskies a bad name..
order allow,deny
deny from 83.222.23.219
allow from all

4. Modifying the Environment Variable

Environment variables contain information used by server-side includes and CGI. Set / Unset environment variables using SetEnv and UnSetEnv. 
SetEnv SITE_WEBMASTER "Jack Sprat"
SetEnv SITE_WEBMASTER_URI mailto:[email protected]

UnSetEnv REMOTE_ADDR

5. 301 Redirect using htaccess

If you want to redirect from an old document to new: 
Redirect 301 /old/file.html http://yourdomain.com/new/file.html
Use following for redirecting Entire Directory. 
RedirectMatch 301 /blog(.*) http://yourdomain.com/$1

6. Implementing a Caching Scheme with .htaccess

Cache the static files and improve your website’s performance. ) 
# year
<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|swf|mp3|mp4)$">
Header set Cache-Control "public"
Header set Expires "Thu, 15 Apr 2010 20:00:00 GMT"
Header unset Last-Modified
</FilesMatch>
#2 hours
<FilesMatch "\.(html|htm|xml|txt|xsl)$">
Header set Cache-Control "max-age=7200, must-revalidate"
</FilesMatch>
<FilesMatch "\.(js|css)$">
SetOutputFilter DEFLATE
Header set Expires "Thu, 15 Apr 2010 20:00:00 GMT"
</FilesMatch>

7. Compress output using GZIP

Add following snippet into your htaccess file and compress all the css, js, html files with GZip compression. 
<IfModule mod_gzip.c>
    mod_gzip_on       Yes
    mod_gzip_dechunk  Yes
    mod_gzip_item_include file      \.(html?|txt|css|js|php|pl)$
    mod_gzip_item_include handler   ^cgi-script$
    mod_gzip_item_include mime      ^text/.*
    mod_gzip_item_include mime      ^application/x-javascript.*
    mod_gzip_item_exclude mime      ^image/.*
    mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</IfModule>
Above code works only if mod_gzip module is enabled in your webserver. You may want to add following snippet if your webserver provides mod_deflate support. 
<Location>
    SetOutputFilter DEFLATE
      SetEnvIfNoCase Request_URI  \
        \.(?:gif|jpe?g|png)$ no-gzip dont-vary
    SetEnvIfNoCase Request_URI  \
        \.(?:exe|t?gz|zip|gz2|sit|rar)$ no-gzip dont-vary
</Location>
If your webserver does not support mod_deflate then you may want to use following snippet. 
<FilesMatch "\.(txt|html|htm|php)">
 php_value output_handler ob_gzhandler
</FilesMatch>

8. Redirect browser to https (ssl)

Add following snippet to your htaccess and redirect entire website to https. 
RewriteEngine On
RewriteCond %{HTTPS} !on
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

9. Rewrite URLs using htacccess

Rewriting product.php?id=12 to product-12.html 
RewriteEngine on
RewriteRule ^product-([0-9]+)\.html$ product.php?id=$1
Rewriting product.php?id=12 to product/ipod-nano/12.html 
RewriteEngine on
RewriteRule ^product/([a-zA-Z0-9_-]+)/([0-9]+)\.html$ product.php?id=$2
Redirecting non www URL to www URL 
RewriteEngine On
RewriteCond %{HTTP_HOST} ^aizberg\.net$
RewriteRule (.*) http://www.aizberg.net/$1 [R=301,L]
Rewriting yoursite.com/user.php?username=xyz to yoursite.com/xyz 
RewriteEngine On
RewriteRule ^([a-zA-Z0-9_-]+)$ user.php?username=$1
RewriteRule ^([a-zA-Z0-9_-]+)/$ user.php?username=$1
Redirecting the domain to a new subfolder of inside public_html 
RewriteEngine On
RewriteCond %{HTTP_HOST} ^test\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.test\.com$
RewriteCond %{REQUEST_URI} !^/new/
RewriteRule (.*) /new/$1

10. Prevent Directory Listing

Add any of the following snippet to avoid directory listing. 
Options -Indexes
or 
IndexIgnore *

11. Adding new MIME types

The type of file depends on the filename extension. Unrecognized file extensions are treated as text data, and corrupted on download. 
AddType application/x-endnote-connection enz
AddType application/x-endnote-filter enf
AddType application/x-spss-savefile sav

12. Deny access to static file data

Denies any request for static files (images, css, etc) if referrer is not local site or empty. 
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteCond %{HTTP_REFERER} !^http://www.askapache.com.*$ [NC]
RewriteRule \.(ico|pdf|flv|jpg|jpeg|mp3|mpg|mp4|mov|wav|wmv|png|gif|swf|css|js)$ - [F,NS,L]

13. Specify Upload file limit for PHP in htaccess

php_value upload_max_filesize 20M
php_value post_max_size 20M
php_value max_execution_time 200
php_value max_input_time 200
In the above .htaccess file, uploading capability is increased by the four parameter first one is maximum file size for uploading, second one is maximum size of the post data , third one is maximum time in seconds a script is allowed to run before it is terminated by the parser and last one is maximum time in seconds a script is allowed to parse input data such as like file uploads, POST and GET data.

14. Disallow Script Execution

Options -ExecCGI
AddHandler cgi-script .php .pl .py .jsp .asp .htm .shtml .sh .cgi

15. Change Charset and Language headers

AddDefaultCharset UTF-8
DefaultLanguage en-US

16. Set Timezone of the Server (GMT)

SetEnv TZ America/Indianapolis

17. Force “File Save As” Prompt

AddType application/octet-stream .avi .mpg .mov .pdf .xls .mp4

18. Protecting a single file

Normally .htaccess applies to the entire directory. With the directive you can restrict it to specific files: 
<Files quiz.html>
order deny,allow
deny from all
AuthType Basic
AuthName "Characterology Student Authcate"
AuthLDAP on
AuthLDAPServer ldap://directory.characterology.com/
AuthLDAPBase "ou=Student, o=Characterology University, c=au"
require valid-user
satisfy any
</Files>

19. Set Cookie using htaccess

Set Cookie with environment variable 
Header set Set-Cookie "language=%{lang}e; path=/;" env=lang
Set Cookie based on Request. This code sends the Set-Cookie header to create a cookie on the client with the value of a matching item in 2nd parentheses. 
RewriteEngine On
RewriteBase /
RewriteRule ^(.*)(de|es|fr|it|ja|ru|en)/$ - [co=lang:$2:.yourserver.com:7200:/]

20. Send Custom Headers

Header set P3P "policyref=\"http://www.askapache.com/w3c/p3p.xml\""
Header set X-Pingback "http://www.askapache.com/xmlrpc.php"
Header set Content-Language "en-US"
Header set Vary "Accept-Encoding"

21. Blocking request based on User-Agent Header

SetEnvIfNoCase ^User-Agent$ .*(craftbot|download|extract|stripper|sucker|ninja|clshttp|webspider|leacher|collector|grabber|webpictures) HTTP_SAFE_BADBOT
SetEnvIfNoCase ^User-Agent$ .*(libwww-perl|aesop_com_spiderman) HTTP_SAFE_BADBOT
Deny from env=HTTP_SAFE_BADBOT
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