The host at this IP address is infected with the CryptPHP PHP malware.
CryptoPHP is a threat that uses backdoored Joomla, WordPress andn Drupal themes and plug-ins to compromise webservers on a large scale. More information about this threat can be found on the referenced link below.
Fox-IT: CryptoPHP - Analysis of a hidden threat inside popular content management systems
Attackers Using Compromised Web Plug-Ins in CryptoPHP Blackhat SEO Campaign
This infection almost certainly means that the infected web site has used pirated plugins from the nulledstylez.com, dailynulled.com sites or some other site that specializes in providing "nulled" (pirated) software. Fox-IT's research has shown that every pirated theme or plug-in on these two sites has been infested with the cryptophp malware.
This was detected by a TCP connection from 188.8.131.52 on port 44874 going to IP address 184.108.40.206 (the sinkhole) on port 80.
The botnet command and control domain for this connection was "carandfly.net".
Behind a NAT, you should be able to find the infected machine by looking for attempted connections to IP address 220.127.116.11 or host name carandfly.net on any port with a network sniffer such as wireshark or by configuring the router to block and log such connections. Equivalently, you can examine your DNS server or proxy server logs to references to 18.104.22.168 or carandfly.net. See Advanced Techniques for more detail on how to use wireshark - ignore the references to port 25/SMTP traffic - the identifying activity is NOT on port 25.
This detection corresponds to a connection at 2014-11-23 10:09:06 (GMT - this timestamp is believed accurate to within one second).
Note that in the description below, findbot can sometimes yield a lot of false positives. In this case, you are probably looking for references to "social.php", so grepping the output of findbot for "social.php", may work better.