I had a fresh Red Hat 6.0 install and had commented out the telnet line of /etc/inetd.conf. Yet, I came to know that my machine got hacked and anyone could gain root access without a username/passwd prompt just by doing 'telnet <host> <port>' where the <port> was a string, not a number. Is this a common bug? What exact security patches do I need to prevent this from happening again? Thanks.
I forgot to mention: the bug tracker won't allow me to enter this as 'Component Text' so I'm sending this under 'bind' component.
Someone almost certainly started a daemon to allow this, or modified your inetd.conf. To give you any more details, I'd need to know which string was used, as ports *can* be specified as strings (the translation to port numbers is done by looking into /etc/services). This particular entry was almost certainly an exploit of a "service" the hacker started on your machine before that (probably something along the lines of adding something stream tcp nowait root /bin/bash to /etc/inetd.conf). There are two known security bugs in Red Hat Linux 6.0; one is in wu-ftpd, the other is in bind. Update to the current versions of wu-ftpd and bind, and triple-check your system for trojan horses.