Security Updates for Microsoft SharePoint Server 2016 (October 2020)

high Nessus Plugin ID 141436

Synopsis

The Microsoft SharePoint Server 2016 installation on the remote host is affected by multiple vulnerabilities.

Description

The Microsoft SharePoint Server 2016 installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities :

- An information disclosure vulnerability exists when Microsoft SharePoint Server fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the users system. (CVE-2020-16948, CVE-2020-16953)

- A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the SharePoint application pool and the SharePoint server farm account.
Exploitation of this vulnerability requires that a user uploads a specially crafted SharePoint application package to an affected version of SharePoint. The security update addresses the vulnerability by correcting how SharePoint checks the source markup of application packages. (CVE-2020-16951, CVE-2020-16952)

- This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server. An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited this vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. These 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 victim, such as change permissions, delete content, steal sensitive information (such as browser cookies) and inject malicious content in the browser of the victim.
For this vulnerability to be exploited, a user must click a specially crafted URL that takes the user to a targeted SharePoint Web App site. In an email attack scenario, an attacker could exploit the vulnerability by sending an email message containing the specially crafted URL to the user of the targeted SharePoint Web App site and convincing the user to click the specially crafted URL. (CVE-2020-16944)

- 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. The security update addresses the vulnerability by helping to ensure that SharePoint Server properly sanitizes web requests. (CVE-2020-16945, CVE-2020-16946)

- An information disclosure vulnerability exists when Microsoft SharePoint Server improperly discloses its folder structure when rendering specific web pages. An attacker who took advantage of this information disclosure could view the folder path of scripts loaded on the page. To take advantage of the vulnerability, an attacker would require access to the specific SharePoint page affected by this vulnerability. The security update addresses the vulnerability by correcting how scripts are referenced on some SharePoint pages.
(CVE-2020-16941, CVE-2020-16942)

Solution

Microsoft has released KB4486677 to address this issue.

See Also

https://support.microsoft.com/en-us/help/4486677

Plugin Details

Severity: High

ID: 141436

File Name: smb_nt_ms20_oct_office_sharepoint_2016.nasl

Version: 1.11

Type: local

Agent: windows

Published: 10/13/2020

Updated: 6/6/2024

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.2

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.6

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2020-16952

CVSS v3

Risk Factor: High

Base Score: 8.7

Temporal Score: 8.1

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C

CVSS Score Source: CVE-2020-16946

Vulnerability Information

CPE: cpe:/a:microsoft:sharepoint_server:2016, cpe:/a:microsoft:sharepoint_foundation

Required KB Items: SMB/MS_Bulletin_Checks/Possible

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/13/2020

Vulnerability Publication Date: 10/13/2020

Exploitable With

Core Impact

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

Reference Information

CVE: CVE-2020-16941, CVE-2020-16942, CVE-2020-16944, CVE-2020-16945, CVE-2020-16946, CVE-2020-16948, CVE-2020-16951, CVE-2020-16952, CVE-2020-16953

IAVA: 2020-A-0460-S

MSFT: MS20-4486677

MSKB: 4486677