Microsoft SharePoint Server contains a vulnerability that could allow an authenticated, remote attacker to conduct cross-site scripting attacks on a targeted system. Updates are available.
A vulnerability in Microsoft SharePoint Server could allow an authenticated, remote attacker to conduct cross-site scripting (XSS) attacks.
The vulnerability exists because the affected software fails to perform sufficient validation and sanitation of user-supplied input when processing crafted POST requests. An attacker could exploit the vulnerability by convincing a user to follow a malicious link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected site or access sensitive browser-based information.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Microsoft SharePoint Foundation 2010 SP1 and SP2
Microsoft SharePoint Server 2010 SP1 and SP2
Microsoft SharePoint Foundation 2013
Microsoft SharePoint Server 2013
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 resolved the vulnerability by correcting the way that SharePoint Server processes user input validation and sanitization when handling POST requests.
Microsoft has released a security bulletin at the following link: MS13-067
An authenticated, remote attacker could exploit this vulnerability to execute arbitrary script or HTML code in the user's browser in the security context of the affected application. This action could allow the attacker to steal sensitive browser-based information, including authentication cookies and recently submitted data, or to take actions on the site as the affected user.
The affected software fails to perform sufficient validation and sanitation of user-supplied input when processing crafted POST requests before returning the input to the user's browser session. When returned to the browser, the malicious parameters may execute in the security context of the affected site.
An authenticated, remote attacker could exploit this vulnerability by convincing a user to follow a crafted URL that is designed to submit malicious input to the vulnerable script. The script may return that input to the user's browser without proper sanitation and render the input in the security context of the affected site. The attacker could include arbitrary script or HTML code that could allow the attacker to access sensitive browser-based information or execute actions on the site with the privileges of the user.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
Administrators are advised to use an unprivileged account when browsing the Internet.
Administrators are advised to monitor critical 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.
The security vulnerability applies to the following combinations of products.
Office SharePoint Server
2010 SP1, SP2 | 2013 Base
2010 SP1, SP2 | 2013 Base
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