Microsoft Active Directory: Denial of Service -- Existing Account

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2015.2346
 Microsoft Security Bulletin MS15-096 - Important: Vulnerability in Active
              Directory Service Could Allow Denial of Service
                             9 September 2015

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

Product:           Microsoft Active Directory
Publisher:         Microsoft
Operating System:  Windows
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-2535  

Original Bulletin: 
   https://technet.microsoft.com/en-us/library/security/MS15-096

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Microsoft Security Bulletin MS15-096 - Important: Vulnerability in Active 
Directory Service Could Allow Denial of Service (3072595)

Bulletin Number: MS15-096

Bulletin Title: Vulnerability in Active Directory Service Could Allow Denial 
of Service

Severity: Important

KB Article: 3072595

Version: 1.0

Published Date: September 8, 2015

Executive Summary

This security update resolves a vulnerability in Active Directory. The 
vulnerability could allow denial of service if an authenticated attacker 
creates multiple machine accounts. To exploit the vulnerability an attacker 
must have an account that has privileges to join machines to the domain.

This security update is rated Important for all supported editions of Windows
Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 
2012 R2. For more information, see the Affected Software section.

Affected Software

Windows Server 2008

Windows Server 2008 for 32-bit Systems Service Pack 2 (3072595)

Windows Server 2008 for x64-based Systems Service Pack 2

Windows Server 2008 for Itanium-based Systems Service Pack 2

Windows Server 2008 R2 for x64-based Systems Service Pack 1

Windows Server 2008 R2 for Itanium-based Systems Service Pack 1

Windows Server 2012

Windows Server 2012 R2

Server Core installation option

Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core 
installation)

Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core 
installation)

Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core 
installation)

Windows Server 2012 (Server Core installation)

Windows Server 2012 R2 (Server Core installation)

Vulnerability Information

Active Directory Denial of Service Vulnerability - CVE-2015-2535

A denial of service vulnerability exists in Active Directory when an 
authenticated attacker creates multiple machine accounts. An attacker who 
successfully exploited this vulnerability could cause the Active Directory 
service to become non-responsive.

To exploit this vulnerability an attacker must have valid credentials. An 
attacker could exploit this vulnerability by creating multiple machine 
accounts, resulting in denial of service. The update addresses the 
vulnerability by correcting how machine accounts are created.

Microsoft received information about this vulnerability through coordinated 
vulnerability disclosure. When this security bulletin was originally issued 
Microsoft had not received any information to indicate that this vulnerability
had been publicly used to attack customers.

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