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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2007.0391 -- [Solaris] Security Vulnerability in the sshd(1M) Protocol Version 1 Implementation May Allow a Denial of Service to the Host 2 July 2007 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: sshd Publisher: Sun Microsystems Operating System: Solaris 10 Solaris 9 Impact: Denial of Service Access: Remote/Unauthenticated CVE Names: CVE-2006-4924 Ref: ESB-2006.0709 Original Bulletin: http://sunsolve.sun.com/search/printfriendly.do?assetkey=1-26-102962-1 Revision History: July 2 2007: Patches released for Solaris 9 June 28 2007: Patches released for Solaris 10 June 11 2007: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Sun(sm) Alert Notification * Sun Alert ID: 102962 * Synopsis: Security Vulnerability in the sshd(1M) Protocol Version 1 Implementation May Allow a Denial of Service to the Host * Category: Security * Product: Solaris 9 Operating System, Solaris 10 Operating System * BugIDs: 6477720 * Avoidance: Patch, Workaround * State: Resolved * Date Released: 08-Jun-2007, 29-Jun-2007 * Date Closed: 29-Jun-2007 * Date Modified: 21-Jun-2007, 26-Jun-2007, 29-Jun-2007 1. Impact A security vulnerability which affects the sshd(1M) daemon when configured to use protocol version 1 may allow a remote user to cause the daemon to consume an excessive amount of CPU power. This will affect the performance and responsiveness of the system as a whole, resulting in a denial of service (DoS) to the system. This issue is also referenced in the following document: CVE-2006-4924 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4924 2. Contributing Factors This issue can occur in the following releases: SPARC Platform * Solaris 9 without patch 113273-15 * Solaris 10 without patch 123324-03 x86 Platform * Solaris 9 without patch 114858-12 * Solaris 10 without patch 123325-03 Notes: 1. Solaris 8 does not include the sshd(1M) daemon and is therefore not impacted by this issue. 2. This issue only affects systems which are configured to run the SSH service with version 1 of the SSH protocol. A command such as the following can be used to determine if the sshd daemon is running on a host: $ pgrep sshd || echo "sshd not running" To determine if sshd is configured to use version 1 of the protocol, a command such as the following can be used to list the configured protocols from the default configuration file (see sshd_config(4)): $ grep Protocol /etc/ssh/sshd_config Protocol 2,1 If '1' is included in the list of configured protocols (or if no 'Protocol' line is found as the default setting is '2,1'), then the host is potentially affected by this issue; note that in order for protocol version 1 to be truly supported on the host it must be provided with a compatible host key via the HostKey directive, see sshd_config(4) for more details. 3. Symptoms If this issue is exploited to cause a denial of service on the host, one or more sshd processes will be running and will be consuming an unusually large percentage of CPU time. In addition, the host itself may be generally unresponsive. To determine the CPU usage of the processes running on the system, a command such as the following can be used, which will sort the running process by CPU consumption (in descending order): $ prstat -s cpu [...] 4. Relief/Workaround To work around the described issue, sites may choose to disable version 1 of the protocol by removing '1' from the list of supported protocols in the /etc/ssh/sshd_config file (see sshd_config(4)). E.g.: $ grep Protocol /etc/ssh/sshd_config Protocol 2 and then restart the sshd daemon: For Solaris 9: # /etc/init.d/sshd stop ; /etc/init.d/sshd start For Solaris 10: # svcadm restart ssh 5. Resolution This issue is addressed in the following releases: SPARC Platform * Solaris 9 with patch 113273-15 or later * Solaris 10 with patch 123324-03 or later x86 Platform * Solaris 9 with patch 114858-12 or later * Solaris 10 with patch 123325-03 or later Change History 21-Jun-2007: * Updated Contributing Factors and Resolution sections 26-Jun-2007: * Updated Contributing Factors and Resolution sections 29-Jun-2007: * Updated Contributing Factors and Resolution sections * State: Resolved 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 2000-2006 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 iQCVAwUBRoh/Kyh9+71yA2DNAQIPuwP/diaCH0JM7pG2r/RM5R9tdRlld1mlnGKk ir12kF0x4akWUZMhC8ErFJ6nuORATWUX8S54UMNoD/P1Zx18HiWtBv0lPiv7hA/S 3D8L//+0fi5nXzzZ/tWUZt9oQUN2Fg0D3GuxOzzPJJTCSpVk4qxVrdymWSEw4UIT TrDmIdkfmf4= =2jq8 -----END PGP SIGNATURE-----