Microsoft SharePoint Server-Side Include (SSI) and ViewState RCE

This vulnerability occurs when the software fails to check the source markup of an application package, which leads to Remote Code Execution vulnerability in Microsoft SharePoint. Through page creation privileges permission in SharePoint, an unauthenticated user could exploit this bug by the means of leaking an arbitrary file, mainly the application’s web.config file, which could be utilized to perform RCE via .NET deserialization.

Impact

The attacker will be able to execute malicious code on the target server or client with high privileges.

Affected versions:

• icrosoft SharePoint Enterprise Server 2016
• Microsoft SharePoint Server 2019
• Microsoft SharePoint Foundation 2013 Service Pack 1

Mitigation / Precaution

In order to patch this vulnerability, we suggest you to test and apply the patched versions (https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16952).

Written by

Anandhu K A

Lead Engineer