Get Valid Logins on RedHat 4.x

[GoldMatrix () AOL COM (GoldMatrix)]

I'm not sure if this is an old problem or not but here goes...

While I was messing with my Red Hat Linux today I noticed that if you put in a
login name that does not exist, and enter a password it will disconnect you.
But if you enter a valid login name, with the wrong password, it won't
disconnect, it will ask for the login over again.

This could be used very easily to get valid login names, and then try to get
their password.

-Zach