mailing list archives
TESO & C-Skills development advisory -- kreatecd
From: krahmer () CS UNI-POTSDAM DE (Sebastian)
Date: Thu, 16 Mar 2000 14:40:35 +0100
This one is very strange.
I hate GUIS. Still ...
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TESO Security Advisory
kreatecd local root compromise
A vulnerability within the kreatecd application for Linux has been
discovered. An attacker can gain local root-access.
Any system which has kreatecd installed as set-UID root.
This affects also a configure; make; make install procedure.
Among the vulnerable distributions (if the package is installed) are the
Halloween Linux Version 4
[stealth () liane stealth]$ stat `which kreatecd`
Size: 229068 Filetype: Regular File
Mode: (4755/-rwsr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Device: 3,1 Inode: 360053 Links: 1
Access: Tue Mar 14 14:48:21 2000(00000.00:00:45)
Modify: Tue Mar 14 14:48:21 2000(00000.00:00:45)
Change: Tue Mar 14 14:48:21 2000(00000.00:00:45)
[stealth () liane stealth]$ id
uid=500(stealth) gid=500(stealth) groups=500(stealth)
[stealth () liane stealth]$ /tmp/kreatur
(... some diagnostic messages ...)
Execute kreatecd and follow the menus:
Configure -> Paths -- change the path for cdrecord to /tmp/xxx
Apply -> OK
Configure -> SCSI -> OK
(poking around with GUI...)
[stealth () liane stealth]$ /tmp/boomsh
[root () liane stealth]# id
uid=0(root) gid=500(stealth) groups=500(stealth)
[root () liane stealth]#
An attacker may gain local root-access to a system where vulnerable
kreatecd package is installed. It might be difficult for an remote-
attacker who gained local user-access due to the GUI-nature of
the vulnerable program.
I appreciate help with some tips how one can get an instant rootshell
without clicking around.
Kreatecd which runs with the saved user-id of 0 blindly trusts path's to
cd-recording software given by unprivileged user.
It then invokes this software with EUID of 0 when user just clicks a little
bit around with the menus.
The author and the distributor has been informed before.
Remove the suid bit of kreatecd.
The bug-discovery and the demonstration programs are due to S. Krahmer .
This advisory has been written by S. Krahmer.
The TESO crew can be reached by mailing to teso () coredump cx
Our web page is at https://teso.scene.at/
C-Skills developers may be reached through .
 S. Krahmer, C-Skills
http://teso.scene.at or https://teso.scene.at/
This advisory does not claim to be complete or to be usable for any
purpose. Especially information on the vulnerable systems may be
inaccurate or wrong. The supplied exploit is not to be used for malicious
purposes, but for educational purposes only.
This advisory is free for open distribution in unmodified form.
Articles that are based on information from this advisory should include
link  and .
We've created a working demonstration program to exploit the vulnerability.
The exploit is available from
http://teso.scene.at/ or https://teso.scene.at/
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- Re: Exploit for Mandrake 6.1 (PAM/userhelper bug), (continued)