CVE-2020-1499: 
vulnerability analysis and mitigation

A spoofing vulnerability (CVE-2020-1499) was identified in Microsoft SharePoint Server that occurs when the server fails to properly sanitize specially crafted web requests. The vulnerability was disclosed and patched by Microsoft in August 2020, affecting multiple versions of SharePoint including SharePoint Enterprise Server 2013 SP1, SharePoint Enterprise Server 2016, and SharePoint Server 2019 (CVE Details, Microsoft Support).

The vulnerability requires authentication and can be exploited by sending a specially crafted request to an affected SharePoint server. When successfully exploited, it allows attackers to perform cross-site scripting (XSS) attacks and execute scripts in the security context of the current user. The vulnerability received a CVSS v3.1 Base Score of 5.4 (Medium) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (NVD).

The successful exploitation of this vulnerability could allow attackers to read unauthorized content, use the victim's identity to perform actions on the SharePoint site (such as changing permissions and deleting content), and inject malicious content into the user's browser (CVE Details).

The vulnerability requires authentication for exploitation, meaning an attacker must have valid credentials to the SharePoint server to attempt exploitation. The attack complexity is considered low, requiring no special conditions or circumstances for exploitation (NVD).

Microsoft addressed this vulnerability by implementing improved web request sanitization in SharePoint Server. Security updates were released for affected versions: KB4484479 for SharePoint Server 2013 SP1, KB4484473 for SharePoint Server 2016, and KB4484472 for SharePoint Server 2019. Users are advised to apply these security updates through Microsoft Update, Microsoft Update Catalog, or Microsoft Download Center (Microsoft Support).