Here is another example how your site got hacked. I found this instance very recently in Godaddy server. This type of site hacking is not very common. You may not be able to detect any specific web page infected if you search your site using Google Diagonestic tool for safe browsing mentioned in my earlier post – Iframe code injection. In this kind of attack none of your web pages get infected but your .htaccess file gets modified and becomes the main source of redirection to malware containing site. Let me show you an infected .htaccess file for example.
Experienced developer can understand why this is so dangerous. Let me explain a little for the newbies. In case of apache web server configuration directives are described in httpd.conf file. Many cases this file can’t be accessed or modified due to security reasons. So to change some configuration directives for a specific website or its sub directory best solution is to use .htaccess file. To know further about .htaccess file and its functionality you can read .htaccess files. However URL rewriting, URL redirection, authentication are the important functionality .htaccess file are used for.
In the example htaccess file there are 3 sections. First line is for instructing the apache web server to put the rewrite engine on. This is first section. Second section goes from line no. 2 to line no. 8. This section is basically for condition checking on URL. Its checking if the visitors are coming from a website or page with URL containing the following words like google, aol, msn, yahoo, yandex, rambler or ya. NC means pattern checking will be case insensitive. OR means combines with other rule. Third section is in line no. 9. It says if any of the above pattern checking become true then it will redirect to the specified URL. Here R means redirection. Normally this generates HTTP response code 302 means moved temporarily. L means this is the last rule.
So the result is that if some visitor coming to the site from above specified search engine, they will be simply redirected to the malware site without understanding whats happening. So be careful if you come to know your site gotta hacked and youre unable to find out why then take a look at your .htaccess file.