Find-Date utility is intended to search files (shells) filled to your site by an attacker. The principle of utility is very simple. It shows file creation time. If the file has been filled, its date will be later than the date of all other files. Certainly it does not always happen like this because in rare cases the filled file can change its date by itself. But more often test by date is sufficient. The script will show all dates of the files in sorted order and you can see all the files created during this time selecting one of the dates.
You can download the script here (version 0.1.0).
1. Copy file find-date.php to the root of your site.
2. Open file http://your web site / find-date.php in your browser.
I wish you less problems with your project security!