-----BEGIN PGP SIGNED MESSAGE-----

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                ESB-2003.0637 -- OpenBSD Security Advisory
   Vulnerability in Semaphore Limits May Allow Lowering Security Levels
                             11 September 2003

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                kernel
Publisher:              OpenBSD
Operating System:       OpenBSD 3.3
Impact:                 Reduced Security
Access Required:        Existing Account

- --------------------------BEGIN INCLUDED TEXT--------------------

[ Please note: this bug affects OpenBSD 3.3 only.  Prior versions do
not have runtime-configurable semaphore limits. ]

It is possible for root to raise the value of the seminfo.semmns
and seminfo.semmsl sysctls to values sufficiently high such that
an integer overflow occurs.  This can allow root to write to kernel
memory irrespective of the security level.  The default security
level on OpenBSD is 1 ("secure mode") which does not allow writing
to /dev/mem and /dev/kmem.  It may be possible for a root user
to exploit this bug to reduce the security level itself.

The impact of this bug is quite low for most systems since it is
only useful to an attacker who already has root on the local system
with the expertise to modify the running kernel.

Thanks to blexim for finding this bug and notifying us.

The problem has been fixed in the OpenBSD 3.3-stable branch.
In addition, a patch is available for OpenBSD 3.3:
    ftp://ftp.openbsd.org/pub/OpenBSD/patches/3.3/common/003_sysvsem.patch

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/render.html?cid=1980

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

        http://www.auscert.org.au/render.html?it=3192

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business 
                hours which are GMT+10:00 (AEST).  On call after hours 
                for member emergencies only.
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967

iQCVAwUBP2AV/Ch9+71yA2DNAQFrKgP/Q5uBAoPfKAF2wgl4L5gqulieNVn+JvDV
KwmQL3tsI+INrhJ0tlE6XU1CWtOe3L1tsH4KAyRs7iVHJt6NlX5mgVTwtIPRxqGw
iZ853Gp/5sYTAAvciMwxPL7IasSg1d/jiM+EAeU3pjnw4ni5Fkar6ZAmQW2njB2S
iU1AgXg3QKw=
=8QVu
-----END PGP SIGNATURE-----