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-----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-----