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Microsoft SharePoint 2013 SP1 Stored XSS Vulnerability

High
Advisory ID
ZSL-2019-5533
Release Date
24 September 2019
Vendor
Microsoft Corporation - https://www.microsoft.com
Affected Version
2013 SP1
Tested On
Microsoft Windows Server 2016, Microsoft Sharepoint 2013 SP1
Summary

SharePoint is a web-based collaborative platform that integrates with Microsoft Office. Launched in 2001, SharePoint is primarily sold as a document management and storage system, but the product is highly configurable and usage varies substantially among organizations.

Description

A cross-site-scripting (XSS) vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server. An authenticated attacker could exploit the vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited the vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. The attacks could allow the attacker to read content that the attacker is not authorized to read, use the victim's identity to take actions on the SharePoint site on behalf of the user, such as change permissions and delete content, and inject malicious content in the browser of the user. Sharepoint 2013 SP1 allows users to upload files to the platform, but does not correctly sanitize the filename when the files are listed. An authenticated user that has the rights to upload files to the SharePoint platform, is able to exploit a Stored Cross-Site Scripting vulnerability in the filename. The filename is reflected in the attribute 'aria-label' of the following HTML tag.

Proof of Concept
Disclosure Timeline
12.05.2019Vulnerability discovered.
13.05.2019Vendor contacted.
14.05.2019Response from the vendor.
11.09.2019Patch released from the vendor.
24.09.2019Coordinated public security advisory released.
Credits
Vulnerability discovered by Davide Cioccia
References
Changelog
24.09.2019Initial release
25.09.2019Added reference [4]
26.09.2019Added reference [5]