Path: utzoo!attcan!uunet!wuarchive!julius.cs.uiuc.edu!apple!uokmax!sean!mka
From: mka@sean.UUCP (mka)
Newsgroups: comp.sys.ncr
Subject: Re: how do I resurrect an old tower
Summary: if you can't find a disk ...
Keywords: ncr tower
Message-ID: <134@sean.UUCP>
Date: 21 Oct 90 01:36:12 GMT
References: <1990Oct19.102703.3693@quagga.uucp>
Organization: Intelligent Systems, Okla. City
Lines: 55

If you can't get a disk, which I guess would be a standalone shell (by
the way, which tower do you have and which version of Unix?), then you
may still be able to get in.

I have broken into two towers under the same circumstances using the
following method. I don't remember the specific details but I'll describe
the concept.

1. you must be able to get on the machine (log in) with any uid possible.
This means find an unprotected login (no password). The ones I try are
	sa
	startup
	shutdown
	daemon
	sys
	bin
	adm
	ncrm
	uucp
	guest
"uucp" and "ncrm" are often left unprotected for some strange reason.

2. once you get in, you need to be able to get a shell. this may involve
trying keyboard interrupts to break out of menus.

3. once you get a shell, create a filesystem on a floppy. I'm not sure
if the standard commands allow you to do this (format, mkfs,etc.), but
you may be able to "dd" the harddisk filesystem or at least the hard
disk superblock onto the filesystem. or you could write a small C
program that builds a superblock with the right values and writes it
to the floppy.

4. then using fsdb, patch the unmounted file system to the right size,
create inodes, create a directory (if its not there), and generally
create a filesystem with a root directory.

5. using fsdb, create a file with zero length (really, allocate an inode
as a file), make the owner root, and then set the permissions to be setuid
plus read+write for everyone. make a directory entry that references
the inode.

6. mount the floppy filesystem in a convenient directory. copy /bin/sh
to your setuid file.

7. execute the setuid shell and then edit /etc/passwd. done.

Well, after describing the above, its obvious that I have forgotten a
zillion details, and this is not a trivial task. At least not for
Unix novices, and I don't know the level of your unix knowledge. 

I hope you find a disk.

Good luck,
Mike Anderson
{uunet|uokmax}!sean!mka