[4556] in WWW Security List Archive
Re: Bugz in System V
daemon@ATHENA.MIT.EDU (Judy Wheeler (TBE))
Fri Feb 21 10:52:08 1997
Date: Fri, 21 Feb 1997 08:34:56 -0500
From: judy@rayleigh.TT.AFTAC.GOV (Judy Wheeler (TBE))
To: www-security@ns2.rutgers.edu
Errors-To: owner-www-security@ns2.rutgers.edu
hitman@sure.net wrote:
>
> Im in the process of setting up a Unix Server and was wondering if there
> are any security bugz in the latest version.
>
I have not seen it posted in this group but one bug to watch our for
in UNIX is this one. It may have been fixed in 2.6...
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AUSCERT has received information that a vulnerability exists in
ffbconfig(1m), distributed under Solaris 2.5 and 2.5.1.
This vulnerability may allow local users to gain root privileges.
Exploit information involving this vulnerability has been made publicly
available.
At this stage, AUSCERT is unaware of any official vendor patches. AUSCERT
recommends that sites apply the workaround given in Section 3 until vendor
patches are made available.
This advisory will be updated as more information becomes available.
- ----------------------------------------------------------------------------
1. Description
ffbconfig is a program used to configure the Fast Frame Buffer
(FFB) Graphics Accelerator, and is part of the FFB Configuration
Software package, SUNWffbcf. This software is only of use if the FFB
Graphics accelerator card is installed. If the device /dev/fbs/ffb0
exists, it may indicate that the card is installed.
Due to insufficient bounds checking on arguments which are supplied
by users, it is possible to overwrite the internal stack space of the
ffbconfig program while it is executing. By supplying a carefully
designed argument to the ffbconfig program, intruders may be able to
force ffbconfig to execute arbitrary commands. As ffbconfig is setuid
root, this may allow intruders to run arbitrary commands with root
privileges.
ffbconfig was first released under Solaris 2.5 and 2.5.1, and this
vulnerability is known to affect both these releases.
Sites can determine if this package is installed by checking for the
SUNWffbcf package:
% /usr/bin/pkginfo -l SUNWffbcf
ffbconfig is installed by default in /usr/sbin. Sites are encouraged
to check for the presence of this program regardless of the version
of Solaris installed.
Exploit information involving this vulnerability has been made
publicly available.
Sun Microsystems has informed AUSCERT that they are currently working
on this vulnerability.
2. Impact
Local users may gain root privileges.
3. Workarounds/Solution
AUSCERT recommends that sites prevent the exploitation of this
vulnerability in ffbconfig by immediately applying the
workaround given in Section 3.1. If the SUNWffbcf package
is not required, it is recommended that sites remove it from their
systems (Section 3.2).
Currently there are no vendor patches available that address this
vulnerability. AUSCERT recommends that official vendor patches be
installed when they are made available.
3.1 Remove setuid and non-root execute permissions
To prevent the exploitation of the vulnerability described in this
advisory, AUSCERT recommends that the setuid permissions be removed
from the ffbconfig program immediately. As ffbconfig will no longer
work for non-root users, it is recommended that the execute permissions
also be removed.
# ls -l /usr/sbin/ffbconfig
-r-sr-xr-x 1 root bin 31436 Oct 14 1995 /usr/sbin/ffbconfig
# chmod 500 /usr/sbin/ffbconfig
# ls -l /usr/sbin/ffbconfig
-r-x------ 1 root bin 31436 Oct 14 1995 /usr/sbin/ffbconfig
3.2 Remove the SUNWffbcf package
If the FFB graphics accelerator card is not installed, the SUNWffbcf
package will not be required and sites are encouraged to remove it
completely from their systems. This can be done by running, as root,
the command:
# /usr/sbin/pkgrm SUNWffbcf
There are also a number of other packages which are also associated
with the FFB Graphics Accelerator:
SUNWffb FFB System Software (Device Driver)
SUNWffbmn On-Line FFB Manual Pages
SUNWffbw FFB Window System Support
SUNWffbxg FFB XGL support
Although there is nothing to suggest that these packages contain
vulnerabilities, if you do not require their functionality, you may
also wish to remove them with the /usr/sbin/pkgrm command.
4. Additional measures
Most Unix systems ship with numerous programs which have setuid or
setgid privileges. Often the functionality supplied by these
privileged programs is not required by many sites. The large number
of privileged programs that are shipped by default are to cater for
all possible uses of the system.
AUSCERT encourages sites to examine all the setuid/setgid programs
and determine the necessity of each program. If a program does not
absolutely require the setuid/setgid privileges to operate (for
example, it is only run by the root user), the setuid/setgid
privileges should be removed. Furthermore, if a program is not
required at your site, then all execute permissions should be removed.
A sample command to find all setuid/setgid programs is (run as root):
# find / \( -perm -4000 -o -perm -2000 \) -type f -exec ls -l {} \;
It is AUSCERT's experience that many vulnerability are being discovered
in setuid/setgid programs which are not necessary for the correct
operation of most systems. Sites can increase their security
by removing unnecessary setuid/setgid programs.
For example, the functionality provided by the ffbconfig program is
not needed by many sites. If sites had previously disabled this
program, they would not have been susceptible to this latest
vulnerability.
- ----------------------------------------------------------------------------
[ End AUSCERT Advisory ]
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of AUSCERT, Sun Microsystems &
DFN-CERT for the information contained in this bulletin.
_______________________________________________________________________________
/ AFTAC / Judy Wheeler Unix System Administrator
/ PATRICK AFB / (407) 494-5481 judy@rayleigh.tt.aftac.gov
/ COCOA BEACH /
/ FLORIDA /
