Microsoft Unified Access Gateway contains a vulnerability that could allow an unauthenticated, remote attacker to conduct spoofing attacks on a targeted system.† Updates are available.
Microsoft Unified Access Gateway (UAG) contains a vulnerability that could allow an unauthenticated, remote attacker to conduct spoofing attacks against a targeted system.
The vulnerability is due to the mishandling of crafted URLs by the affected software.† This mishandling could allow an unauthenticated, remote attacker to craft a special URL that, when followed, could trick users into believing they are accessing a legitimate website.
Microsoft has confirmed this vulnerability in a security bulletin and has released updated software.
The following Microsoft products are vulnerable:
Microsoft Forefront Unified Access Gateway 2010 SP1 and prior
Microsoft Forefront Unified Access Gateway 2010 SP1 Update 1 and prior
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
Microsoft has addressed this vulnerability with an update that modifies the UAG code to require further verification before redirecting the user to another site.
Microsoft has released a security bulletin at the following link: MS12-026
An unauthenticated, remote attacker could exploit this vulnerability to redirect a user's browser session to a malicious website that is similar to another site. This action could aid the attacker in obtaining sensitive information such as the user's credentials.
The vulnerability occurs because the UAG web interface does not validate and confirm redirections to an external website.
An unauthenticated, remote attacker could redirect an authenticated UAG user to a malicious web page that is designed to look like the originating web page.† A successful exploit could allow the attacker to entice the user to enter sensitive information, such as usernames, passwords, and or other private information.† This information could then be used to launch further attacks against the system or network.
Administrators are advised to apply the appropriate updates.
Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.
Users should verify that unsolicited links are safe to follow.
Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
Administrators are advised to monitor affected systems.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
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.
Forefront Unified Access Gateway
2010 Base, Update 1, SP1
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