A simple Perl script using a build-in module File::Find to validate some files based on combination of file types and ownership

Check Files' Owner

#!/usr/bin/perl
use strict;
use warnings;
use File::Find;
use v5.10;

my @dir   = qw(/Path/To_Your_Dir/);
my $buser = 'Legal_User_Name';
my @danger;

sub compare {
  my $filename = $File::Find::name;
  my $uid = (stat $filename)[4];
  my $user = (getpwuid $uid)[0];
  push @danger, $filename if ($user ne $buser) and $filename =~ /\.php$/;
}

find(\&compare, @dir);
say join "\t", @danger;