use strict;
use warnings;
use Net::SSH::Perl;


my($host, $username, $new_password, $old_password);


$host = "IPADRESSE";
$username = "USERNAME";
$old_password = "PASSWORD";

my $ssh = Net::SSH::Perl->new($host, debug => 1, protocol => 2);
$ssh->login($username, $old_password);


$ssh->register_handler("stderr", sub {
    my($channel, $buffer) = @_;
    my $str = $buffer->bytes;

    if ($str eq "(current) UNIX password: ") {
        $channel->send_data($old_password);
    }

    elsif ($str eq "New UNIX password: ") {
        $channel->send_data($new_password);
    }

    elsif ($str eq "Retype new UNIX password: ") {
        $channel->send_data($new_password);
    }
});

$ssh->cmd('passwd');