Попытка:
$ for file in *; do [ -f "$file" ] && ( mv "$file" "$(echo $file | sed -e 's/ /_/g')" ); done
What flavor of Linux? Try /var/log/apache2/suexec.log, but looks like suexec (Apache) does not have permissions to write to the log file. Appears to be a bot looking for vulnerable scripts.