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Generell ist Sicherheit durch Unklarheit eine der schwächsten Formen von Sicherheit. Aber in manchen Fällen ist ein klein wenig mehr an zusätzlicher Sicherheit wünschenswert.
Ein paar einfache Techniken helfen, PHP zu verstecken, um nach Schwächen in Ihrem System suchende Angreifer unter Umständen langsamer zu machen. Wenn Sie in Ihrer php.ini expose_php auf off setzen, reduzieren Sie damit die zur Verfügung stehenden Informationen.
Eine andere Taktik ist, den Webserver wie z.B. Apache entweder mittels einer .htaccess-Direktive oder in der Apache-Konfigurationsdatei selbst so einzustellen, dass dieser verschiedene Dateitypen durch PHP parst. So können Sie irreführende Dateierweiterungen verwenden:
Beispiel #3 PHP als andere Sprache ausgeben
# Lasse PHP-Code wie andere Arten von Code aussehen AddType application/x-httpd-php .asp .py .pl
Beispiel #4 Verwenden von unbekannten Typen für PHP-Dateierweiterungen
# Lasse PHP Code wie unbekannte Typen aussehen AddType application/x-httpd-php .bop .foo .133t
Beispiel #5 Verwenden von HTML-Typen für PHP-Dateierweiterungen
# Lasse PHP-Code wie HTML aussehen AddType application/x-httpd-php .htm .html
It's a good idea to "hide" PHP anyway so you can write a RESTful web application.
Using Apache Mod Rewrite:
RewriteEngine On
RewriteRule ^control/([^/]+)/(.*)$ sitecontroller.php?control=$1&query=$2
You then use a function like the following as a way to retrieve data (in a zero indexed fashion) from the $_GET superglobal.
<?php
function myGET() {
$aGet = array();
if(isset($_GET['query'])) {
$aGet = explode('/', $_GET['query']);
}
return $aGet;
}
?>
This is only a really basic example of course - you can do a lot with Mod Rewrite and a custom 'GET' function.
You can use this trick for non-direct used PHP files, eg. setting, class, ajax-related ones.
For abcde.php:
<?php
if ('abcde.php' == basename($_SERVER['SCRIPT_FILENAME'])) die ('What?');
?>
Set INI directive "expose_php" to "off" will also help.
You can spoof your PHP to ASP.NET by using:
<?php
error_reporting(0);
header("X-Powered-By: ASP.NET");
?>
The idea of hiding the X-Powered-By in PHP is a flawed attempt at establishing security. As the manual indicates, obscurity is not security. If I were exploiting a site, I wouldn't check what scripting language the site runs on, because all that would matter to me is exploiting it. Hiding the fact that you use [x] language isn't going to prevent me from bypassing poor security.
May some servers not allow you to put this line (i.e this not work)
AddType application/x-httpd-php .asp .py .pl
or
DefaultType application/x-httpd-php
so, the alternative method that really a good one is:
1- In your .htaccess file write:
RewriteEngine on
RewriteBase /dire/ or just /
RewriteRule securename yourfile\.php [T=application/x-httpd-php]
example: all url like
www.example.com/securename parsed as
www.example.com/yourfile.php
2- but here the $_GET not work, but $_POST work, so for dynamic pages like
www.example.com/yourfile.php?page=1 you use
www.example.com/securename?page=1
now: instead of using $_GET use
<?php
$uri = $_SERVER['REQUEST_URI'];
$page = strstr($uri, '=');
$page = substr($page, 1);
$valid_pages = array('1', '2','...');
$page = in_array($page, $valid_pages) ? $page : '1';
//....
?>
and for bad URL you can add this code to .htaccess file
of coarse below the first code in .htaccess
#--
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^.*$ http://www.example.com/securename [L]
The default session identifier-name PHPSESSID is publicly visible in an HTTP cookie and or URL if sessions are used. It can be changed in the php.ini to something more generic to further obscure PHP.
So far I haven't seen a working rewriter of /foo/bar into /foo/bar.php, so I created my own. It does work in top-level directory AND subdirectories and it doesn't need hardcoding the RewriteBase.
.htaccess:
RewriteEngine on
# Rewrite /foo/bar to /foo/bar.php
RewriteRule ^([^.?]+)$ %{REQUEST_URI}.php [L]
# Return 404 if original request is /foo/bar.php
RewriteCond %{THE_REQUEST} "^[^ ]* .*?\.php[? ].*$"
RewriteRule .* - [L,R=404]
# NOTE! FOR APACHE ON WINDOWS: Add [NC] to RewriteCond like this:
# RewriteCond %{THE_REQUEST} "^[^ ]* .*?\.php[? ].*$" [NC]
I use the following in the .htaccess document
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
then the following simple code
<?php
$permalinks = explode("/",$_SERVER['REQUEST_URI']);
$varone = $permalinks[1];
$vartwo = $permalinks[2];
...
?>
I think the best way to hide PHP on Apache and Apache itself is this:
httpd.conf
-------------
# ...
# Minimize 'Server' header information
ServerTokens Prod
# Disable server signature on server generated pages
ServerSignature Off
# ...
# Set default file type to PHP
DefaultType application/x-httpd-php
# ...
php.ini
------------
; ...
expose_php = Off
; ...
Now the URLs will look like this:
http://my.server.com/forums/post?forumid=15
Now hacker knows only that you are using Apache.
Something that has not been mentioned here is also the PHPSESSION id that will be displayed in the URL when passing it from page to page using GET. If users have cookies set to off, this will be visible. This can be reset before any session_start() call with ini_set(). Be aware however that this can't be changed in this way if you use autho session start.
It is unnecessary, to let every Pampelhuber inspect your 'php.ini' files.
Put the following into the .htaccess of your htdocuments' root:
#Obscure 'php.ini' files (where they exist)
RedirectMatch 404 .*php\.ini$
In order to get the PATH_INFO to work in order to pass parameters using a hidden program/trailing slash/"pretty url" in more recent versions of PHP you MUST add "AcceptPathInfo On" to your httpd.conf.
AddType application/x-httpd-php .php .html
AcceptPathInfo On
Try it out with your phpinfo page and you'll be able to search for PATH_INFO.
http://example.com/myphpinfo.php/showmetheway
If you want to drop the .php use one or both of these:
DefaultType application/x-httpd-php
ForceType application/x-httpd-php
You could also do this in .htaccess when you use Apache and your configuration allows you to override :
<Files test>
ForceType application/x-httpd-php
</Files>
That way, you can use the URL test?pop=true without having to fake it by using test/index.php.
See the Apache manual for more info: http://httpd.apache.org/docs/mod/mod_mime#forcetype
In response to the previous messages, for apache, there is a easier way to set files without "." to be executed by PHP, just put this in a ".htaccess" file :
DefaultType application/x-httpd-php
In case there are an Internal Server error(error 500) using the old code below in an .htaccess file, you can replace it with the code modification that must solve the problem.
Old code
-----------
<Files ~ "^[^\.]+$">
ForceType application/x-httpd-php
</Files>
Replacement of the code above(code modification)
------------------------------------------------------------
AddHandler server-parsed .php
<Files ~ "^[^\.]+$">
SetHandler application/x-httpd-php
</Files>
Regards,
Dimitar Tanev
Assign files w/o extension to php interpreter
without using ReWrite module
[clip httpd.conf]
<Files ~ "^[^\.]+$">
ForceType application/x-httpd-php
</Files>
[/clip]
I´ve found an easy way to hide php code and the uri is searchable by google and others...(only for unix or linux)
At first I have some rules in my hide.conf (i made an extra .conf for it (apache 2.0))
For example when I want to mask the index.php
<Files index>
ForceType application/x-httpd-php
</Files>
My problem is, that my code should be readable...
so I made an extra folder for example srv/www/htdocs/static_output
My phpcode is in the includefolder....(for ex. mnt/source/index.php)
Then I made a link in the shell > ln mnt/source/index.php srv/www/htdocs/static_output/index
So the code is readable (with .php extension) in my includefolder and there is only the link in the srv folder without extension(which is called by the browser...).
Keep in mind, if your really freaked out over hiding PHP, GD will expose you.
Go ahead - make an image with GD and open with a text editor.. Somewhere in there you'll see a comment with gd & php all over it.
What about this in a .htaccess file :
RewriteEngine on
RewriteRule ^$ /index.php [L]
RewriteRule ^([a-zA-Z0-9\-\_/]*)/$ /$1/index.php [L]
RewriteRule ^([a-zA-Z0-9\-\_/]*)\.(html|htm)$ /$1.php [L]
RewriteRule ^([a-zA-Z0-9\-\_/]*)$ /$1.php [L]
Typing "sub.domain.foo/anything" loads "/anything/index.php" if 'anything' is a directory, else it loads "/anything.php".
I'm sure you can find mutch better, but it works great on my site :)
You can see if somebody's using PHP just by adding the following to the end of the URL:
?=PHPB8B5F2A0-3C92-11d3-A3A9-4C7B08C10000
If the page is using PHP, this will show the PHP credits.
Setting expose_php to Off in php.ini prevents this.
adding MultiViews to your apache Options config
lets you hide/omit .php in the url without any rewriting, etc...
More fun includes files without file extensions.
Simply add that ForceType application/x-httpd-php bit to an Apache .htaccess and you're set.
Oh yea, it gets even better when you play with stuff like the following:
<?php
substr($_SERVER['PATH_INFO'],1);
?>
e.g. www.example.com/somepage/55
And:
<?php
foreach ( explode('/',$_SERVER['PATH_INFO']) as $pair ) {
list($key,$value) = split('=',$pair,2);
$param[$key] = stripslashes($value);
}
?>
e.g. www.example.com/somepage/param1=value1/param2=value2/etc=etc
Enjoy =)
Using the .php extension for all your scripts is not necessary, and in fact can be harmful (by exposing too much information about your server, and by limiting what you can do in the future without breaking links). There are several ways to hide your .php script extension:
(1) Don't hard code file types at all. Don't specify any dots, and most web servers will automatically find your .php, .html, .pdf, .gif or other matching file. This is called canonical URL format:
www.xxxxxx.com/page
www.xxxxxx.com/directory/
This gives you great flexibility to change your mind in the future, and prevents Windows browsers from making improper assumptions about the file type.
(2) In an Apache .htaccess file use:
RewriteEngine on
RewriteRule page.html page.php
(3) Force the webserver to interpret ALL .html files as .php:
AddType application/x-httpd-php .php3 .php .html
Another technique is to have every file be named index.php and be in it's own directory. Then instead of using for instance http://example.com/foo.php you could use http://example.com/foo/ where foo is a directory with a file called index.php in it.
PS. If you want to use pretty URLs (i.e. hide your .php extensions) AND you have safe-mode=on, the previous example (ForceType) won't work for you. The problem is that safe-mode forces Apache to honor trailing characters in a requested URL. This means that:
http://www.example.com/home
would still be processed by the home script in our doc root, but for:
http://www.example.com/home/contact_us.html
apache would actually look for the /home/contact_us.html file in our doc root.
The best solution I've found is to set up a virtual host (which I do for everything, even the default doc root) and override the trailing characters handling within the virtual host. So, for a virtual host listening on port 8080, the apache directives would look like this:
<VirtualHost *:8080>
DocumentRoot /web/doc_root
Alias /home "/web/doc_root/home.php"
AcceptPathInfo On
</VirtualHost>
Some people might question why we are overriding the trailing characters handling (with the AcceptPathInfo directive) instead of just turning safe-mode=off. The reason is that safe mode sets global limitations on the entire server, which can then be turned on or left off for each specific virtual host. This is the equivilent of blocking all connections on a firewall, and then opening up only the ones you want, which is a lot safer than leaving everything open globally, and assuming your programmers will never overlook a possible security hole.
Another way to hide your .php extensions is to use the Apache ForceType directive (which is often referred to as pretty URLs.) Basically you force Apache to parse a file as PHP that matches the trailing directory name in your URL.
For example, place this directive in your Apache httpd.conf file:
<Location /home>
ForceType application/x-httpd-php
</Location>
and create a php file name "home" in your doc root. This file should not have a .php extension, and can be a php template file. Combined with a function to strip out URL parameters, this can create a new templating system, which can effectively hide your file extensions.
In this example,
http://www.example.com/home/bar.html
would actually use the home script we created, and then the "bar.html" could be used to specify content to include.
Just a thought but if you have changed the extensions that php interprets I would assume you've also changed header.php and footer.php files to the new extension.
EG:
index.php, somefile.php, header.php, footer.php...
Change the Apache directive so PHP interprets .kev files and rename your files:
index.kev, somefile.kev, header.kev, footer.kev
If you leave header and footer as PHP files then it won't understand how to interpret them.
The flipside to this is, if you're running a version of
PHP/Apache which is not known to have exploitable bugs (usually the latest stable version at the time), and an attacker sees this, they may give up before even trying. If they don't, they may continue to attempt their exploit(s).
It really depends on the type of attacker. The educated, security advisory reading attacker vs. script kiddie on the street.
If you're keeping up on patches, version exposition should not be a problem for you.
I usually do:
<code>
RewriteEngine on<br>
RewriteOptions inherit<br>
RewriteRule (.*)\.htm[l]?(.*) $1.php$2 [nocase]<br>
</code>
in .htaccess. You'll need mod_rewrite installed for this .
To hide PHP, you need following php.ini settings
expose_php=Off
display_errors=Off
and in httpd.conf
ServerSignature Off
(min works, but I prefer off)
And use the
ServerTokens min
directive in your httpd.conf to hide installed PHP modules in apache.
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