Advanced .htaccess Security – Block Access to Include Files Using .htaccess
Written by David Walsh on Wednesday, October 10, 2007
When I build websites for clients and myself, I use numerous include files to make my website easy to maintain. These include files may:
- be composed of pure HTML; no server-side programming involved
- be PHP class files; used throughout the website
- composed of both HTML and PHP
- PHP code to produce a specific action; many times, Ajax scripts
Obviously, if a person were to get lucky and guess the path and file name of my include scripts, problems could result, especially if an Ajax script is not secured (but I wouldn’t do that — nor would you, right?). For example, take the following poorly coded bit of PHP that would get run when an AJAX call was made:
//inside file: includes/ajax/delete_id.inc $query = 'DELETE FROM my_table WHERE id = '.$_GET['id']; mysql_query($query);
Imagine if the user changed the ‘id’ in the querystring to “‘ or 1″ — all data would be lost!
Even if my scripts are secure (meaning I use proper validation to make sure they’ve been called correctly), a user/hacker has no business calling an include file. Using .htaccess, we can prevent any attempt by a user to reach an include file:
<Files ~ "\.inc$"> Order allow,deny Deny from all </Files>
The above code tells the server to disallow any requests, by the user, for any file ending in “.inc”. You can easily modify the above .htaccess for your own naming convention and folder structure.
Just another .htaccess tip to make your website more secure!
Epic Discussion
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I want to hear what you have to say! Share your comments and questions below.
Nice one, I’m going to add it the the ultimate htaccess guide at http://www.askapache.com/apache/apache-htaccess.html
where in the .htaccess file do you place that code (the second block of code in your entry)?
@Charles: It shouldn’t matter where in your .htaccess file you place the above snippet.
nice work.
Are you able to add multiple filenames/file paths to the tag?
@pfwd: I believe if you’re clever with regular expressions you should be able to.
This is very cool. A similar trick I use a lot, and I believe Wordpress uses as well, is to check to see if a php file is being accessed directly.
<?php
//this document is called file.php
if (‘file.php’ == basename($_SERVER['SCRIPT_FILENAME']))
die (‘Do not access this page directly.’);
?>
(Please convert my _ to _ )
I used this, but now my AJAX calls to .inc files (sends GET variables and then receives output from .inc file) aren’t working anymore…
Isn’t there a way to define a “Don’t deny from server call” or something (if this makes sense)?
I’m assuming the “deny from all” makes it fail even when a I make an AJAX call to the .inc file.
Any thoughts?
I used this, but now my AJAX calls to .inc files (sends GET variables and then receives output from .inc file) aren’t working anymore…
Isn’t there a way to define a “Don’t deny from server call” or something (if this makes sense)?
I’m assuming the “deny from all” makes it fail even when a I make an AJAX call to the .inc file.
Any thoughts?