-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

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

                        ESB-2008.0814 -- [Solaris]
       Denial of Service Vulnerability in NFSv4 Client Kernel Module
                              20 August 2008

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

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

Product:              Solaris 10
Publisher:            Sun Microsystems
Operating System:     Solaris
Impact:               Denial of Service
Access:               Existing Account

Original Bulletin:    
  http://sunsolve.sun.com/search/printfriendly.do?assetkey=1-66-240546-1

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

   Solution Type: Sun Alert
   Solution  240546 :   Denial of Service Vulnerability in NFSv4 Client
   Kernel Module          
   Bug ID: 6378538

   Product
   Solaris 10 Operating System

   Date of Resolved Release: 18-Aug-2008

   SA Document Body
   Denial of Service Vulnerability in NFSv4 Client Kernel Module:

   1. Impact
   A security vulnerability in the NFSv4 client kernel module may allow a
   local unprivileged user who cooperates with a remote privileged user
   on an NFSv4 server to be able to cause all NFSv4 mounts on client
   systems which have an NFSv4 mount of  the above NFSv4 server to become
   unresponsive.  This is a type of Denial of Service (DoS).
   2. Contributing Factors
   This issue can occur in the following releases:
   SPARC Platform
     * Solaris 10 without patch 137111-05
     * OpenSolaris based upon builds snv_01 through snv_36

   x86 Platform
     * Solaris 10 without patch 137112-05
     * OpenSolaris based upon builds snv_01 through snv_36

   Note 1: Solaris 8 and 9 are not impacted by this issue.
   Note 2: To determine what version of  NFS an NFS mount is using the
   nfsstat(1M) command can be used:
    $ nfsstat -m /mnt/point
    Flags: vers=4,proto=tcp,sec=sys,hard,intr,link,symlink,acl,rsize=1048576,
    wsize=1048576,retrans=10,timeo=600
    Attr cache: acregmin=3,acregmax=60,acdirmin=30,acdirmax=60

   The number after the "vers=" string indicates the version of NFS in
   use for the mounted file system.
   Note 3:  This issue only affects NFS environments where NFSv4 is in
   use as well as automountd(1M).  Solaris 10 and later NFS clients and
   servers default to NFSv4.  This is configurable by editing the
   /etc/default/nfs file (see nfs(4)).
   To determine if the autofs mount/unmount daemon is enabled,  the
   following command can be run:
    $ svcs svc:/system/filesystem/autofs:default
    STATE          STIME    FMRI
    online         Aug_07   svc:/system/filesystem/autofs:default

   Note 4:  OpenSolaris distributions may include additional bug fixes
   above and beyond the build from which it was derived.
   To determine the base build of  OpenSolaris, the following command can
   be used:
    $ uname -v
    snv_86

   3. Symptoms
   If the described issue is exploited, all NFSv4 mounts on systems which
   have an NFSv4 mount on an NFSv4 server which has been compromised will
   become unresponsive. Depending on the file system configuration, this
   may lead to a system hang.
   4. Workaround
   To work around the described issue, NFS client systems can be
   configured not to use NFSv4 by setting "NFS_CLIENT_VERSMAX=3" in
   "/etc/default/nfs". Please refer to nfs(4) documentation.
   5. Resolution
   This issue is resolved in the following releases:
   SPARC Platform
     * Solaris 10 with patch 137111-05 or later
     * OpenSolaris based upon builds snv_37 or later

   x86 Platform
     * Solaris 10 with patch 137112-05 or later
     * OpenSolaris based upon builds snv_37 or later

   For more information on Security Sun Alerts, see Technical
   Instruction ID 213557.
   This Sun Alert notification is being provided to you on an "AS IS"
   basis. This Sun Alert notification may contain information provided by
   third parties. The issues described in this Sun Alert notification may
   or may not impact your system(s). Sun makes no representations,
   warranties, or guarantees as to the information contained herein. ANY
   AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
   WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
   NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT
   YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT,
   INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE
   OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN.
   This Sun Alert notification contains Sun proprietary and confidential
   information. It is being provided to you pursuant to the provisions of
   your agreement to purchase services from Sun, or, if you do not have
   such an agreement, the Sun.com Terms of Use. This Sun Alert
   notification may only be used for the purposes contemplated by these
   agreements. 
   Copyright 2000-2008 Sun Microsystems, Inc., 4150 Network Circle, Santa
   Clara, CA 95054 U.S.A. All rights reserved

- --------------------------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.

NOTE: Third Party Rights
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

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

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

iQCVAwUBSKuYNSh9+71yA2DNAQI2IQP/QDxwMTfme0il40tdjfUbAmQH5Uzrh4Nw
jlVqbQWeTywc8xsGwunYBO7ja00IuWJj4gM1SZXBRNCpT9AwACtrbaduDk41HCd6
a0SDioFj1mb9D3M227XyEG6sYMvMULrB8AO0yBsr7LvA/HgPqVlb4x0euFPoOXcx
wyzmrZqtZmE=
=8ssA
-----END PGP SIGNATURE-----