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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2011.0132 Vulnerability in Active Directory Could Allow Denial of Service 9 February 2011 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Active Directory Publisher: Microsoft Operating System: Windows Server 2003 Impact/Access: Denial of Service -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2011-0040 Original Bulletin: http://www.microsoft.com/technet/security/Bulletin/MS11-005.mspx - --------------------------BEGIN INCLUDED TEXT-------------------- Microsoft Security Bulletin MS11-005 - Important Vulnerability in Active Directory Could Allow Denial of Service (2478953) Published: February 08, 2011 Version: 1.0 General Information Executive Summary This security update resolves a publicly disclosed vulnerability in Active Directory. The vulnerability could allow denial of service if an attacker sent a specially crafted packet to an affected Active Directory server. The attacker must have valid local administrator privileges on the domain-joined computer in order to exploit this vulnerability. This security update is rated Important for Active Directory on all supported editions of Windows Server 2003. For more information, see the subsection, Affected and Non-Affected Software, in this section. The security update addresses the vulnerability by correcting the way that the Active Directory server handles service principal name (SPN) update requests. Affected Software Windows Server 2003 Service Pack 2 Windows Server 2003 x64 Edition Service Pack 2 Windows Server 2003 with SP2 for Itanium-based Systems Vulnerability Information Active Directory SPN Validation Vulnerability - CVE-2011-0040 A denial of service vulnerability exists in implementations of Microsoft Windows Active Directory due to improper validation of service principal names (SPN), which could result in SPN collisions. When this occurs, services that use the SPN will downgrade to NT LAN Manager (NTLM) if configured to negotiate. Services that are not configured to negotiate will become unavailable, resulting in a denial of service condition. An attacker who successfully exploited this vulnerability could cause the affected system to stop responding. - --------------------------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 =========================================================================== 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 iD8DBQFNUczV/iFOrG6YcBERAsyaAKCiXwVezcH/4b7OzBctJQRcw3gp0QCdHuy1 UT4Km9MzcWJAOqD9wo5ugVk= =4Esc -----END PGP SIGNATURE-----