Microsoft has released an additional bulletin to address the machine authentication check validation arbitrary code execution vulnerability in Microsoft Exchange Server.
A vulnerability in Microsoft Exchange and SharePoint Server could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to insufficient validation of user-supplied input by the affected software when handling unassigned workflows. An attacker could exploit the vulnerability by sending malicious content to a targeted system. A successful exploit could allow the attacker to execute arbitrary code with the privileges of the W3WP (W3wp.exe) service account. This could allow the attacker to completely compromise the system.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Microsoft SharePoint Portal Server 2003 SP3
Microsoft Windows SharePoint Services 2.0
Microsoft Windows SharePoint Services 3.0 SP3 (32-bit and 64-bit)
SharePoint Server 2007 SP3 (32-bit and 64-bit)
Microsoft SharePoint Foundation 2010 SP1 and SP2
Microsoft SharePoint Server 2010 SP1 and SP2
Microsoft Exchange Server 2007 SP3 and prior
Microsoft Exchange Server 2010 SP3 and prior
Microsoft Exchange Server 2013 Cumulative Update 3 and prior
To exploit this vulnerability, an attacker may require access to trusted, internal networks to send crafted requests to the affected software. This access requirement could limit the likelihood of a successful exploit.
Microsoft has resolved the vulnerability by properly implementing MAC.
Microsoft has released security bulletins at the following links:MS13-067 and MS13-105
An unauthenticated, remote attacker could exploit the vulnerability to execute arbitrary code with the elevated privileges of the application service account. This could allow the attacker to completely compromise the targeted system.
The vulnerability is due to the insufficient implementation of machine authentication check (MAC) by the affected software when handling unassigned workflows.
An attacker could exploit the vulnerability by sending crafted content to a targeted system. When the affected software processes the malicious content, the attacker could execute arbitrary code with the privileges of the application service account. This could allow the attacker to completely compromise the system.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators may consider implementing viewstate MAC via the EnableViewStateMac attribute.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Administrators are advised to use an unprivileged account when browsing the Internet.
Administrators are advised to monitor affected systems.
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Microsoft Update service. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Version 1, September 10, 2013, 5:54 PM: Microsoft SharePoint Server contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system. Updates are available.
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