sub register {
  my ($self, $qp) = @_;
  $self->register_hook("data_post", "check_kakas");
}

sub check_kakas {
  my ($self, $transaction) = @_;

  # make sure we read from the beginning;
  $transaction->body_resetpos;

  my $line_number = 0;

  while ($_ = $transaction->body_getline) {
    last if $line_number++ > 40;

    return (DENY, "Attached file type not allowed")
       if m/^Content-Type:.*name.*\.(exe|bat|scr|com|pif)/i;

  }

  return (DECLINED);
}