Microsoft software Unified Access Gateway contains a vulnerability that could allow an unauthenticated, remote attacker to access restricted information on a vulnerable system. Updates are available.
Description
Microsoft software Unified Access Gateway (UAG) contains a vulnerability that could allow an unauthenticated, remote attacker to access restricted information on a vulnerable system.
The vulnerability is due to an unsecured access point setting on vulnerable installations of a UAG server. This could allow an unauthenticated, remote attacker to send a crafted HTTPS query to the affected system and obtain restricted information.
Microsoft has confirmed this vulnerability in a security bulletin and has released updated software.
Warning Indicators
The following Microsoft products are vulnerable:
Microsoft Forefront Unified Access Gateway 2010 SP1 and prior
Microsoft Forefront Unified Access Gateway 2010 SP1 and prior Update 1
IntelliShield Analysis
Because this binding is a default setting, any installation of the Unified Access Gateway would be vulnerable if it is not changed manually. It is strongly suggested to apply the update.
Microsoft has addressed this vulnerability with an update that modifies the UAG server's default binding settings to not allow unfiltered access to internal HTTPS resources.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the April 2012 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for April 2012.
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS12-026
Impact
An unauthenticated, remote attacker could exploit this vulnerability to access restricted resources and obtain sensitive information on a vulnerable system. This access and information could be used to conduct further attacks.
Technical Information
The vulnerability is specifically due to a default IIS website binding setting on a UAG server. This default binding on 0.0.0.0 on TCP port 443 allows unfiltered HTTPS access from an external network, allowing unrestricted access to resources on the default website.
An unauthenticated, remote attacker with access to the affected server could send specially crafted HTTPS queries to gain access to restricted resources and obtain sensitive information. This result could lead to further attacks against the system or network.
Safeguards
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
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 monitor affected systems.
Patches/Software
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 Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
The security vulnerability applies to the following combinations of products.
Primary Products:
Microsoft, Inc.
Forefront Unified Access Gateway
2010 Base, SP1, Update 1
Associated Products:
N/A
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