An elevation of privilege vulnerability exists in Azure Active Directory Authentication Library On-Behalf-Of flow, in the way the library caches tokens. This vulnerability allows an authenticated attacker to perform actions in context of another user. The authenticated attacker can exploit this vulneraiblity by accessing a service configured for On-Behalf-Of flow that assigns incorrect tokens. This security update addresses the vulnerability by removing fallback cache look-up for On-Behalf-Of scenarios.

An elevation of privilege vulnerability exists in Dynamics On-Premise v9. An attacker who successfully exploited the vulnerability could leverage a customizer privilege within Dynamics to gain control of the Web Role hosting the Dynamics installation. To exploit this vulnerability, an attacker needs to have credentials for a user that has permission to author customized business rules in Dynamics, and persist XAML script in a way that causes it to be interpreted as code. The update addresses the vulnerability by restricting XAML activities to a whitelisted set.

An information disclosure vulnerability exists when the Windows kernel improperly handles objects in memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the user’s system. To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted application. The vulnerability would not allow an attacker to execute code or to elevate user rights directly, but it could be used to obtain information that could be used to try to further compromise the affected system. The update addresses the vulnerability by correcting how the Windows kernel handles objects in memory.

An information disclosure vulnerability exists when the Windows kernel improperly handles objects in memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the user’s system. To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted application. The vulnerability would not allow an attacker to execute code or to elevate user rights directly, but it could be used to obtain information that could be used to try to further compromise the affected system. The update addresses the vulnerability by correcting how the Windows kernel handles objects in memory.

A remote code execution vulnerability exists in Remote Desktop Services – formerly known as Terminal Services – when an unauthenticated attacker connects to the target system using RDP and sends specially crafted requests. This vulnerability is pre-authentication and requires no user interaction. An attacker who successfully exploited this vulnerability could execute arbitrary code on the target system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would need to send a specially crafted request to the target systems Remote Desktop Service via RDP. The update addresses the vulnerability by correcting how Remote Desktop Services handles connection requests.

An information disclosure vulnerability exists when the Windows RDP server improperly discloses the contents of its memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the system. To exploit this vulnerability, an attacker would have to connect remotely to an affected system and run a specially crafted application. The security update addresses the vulnerability by correcting how the Windows RDP server initializes memory.

An information disclosure vulnerability exists when the Windows RDP server improperly discloses the contents of its memory. An attacker who successfully exploited this vulnerability could obtain information to further compromise the system. To exploit this vulnerability, an attacker would have to connect remotely to an affected system and run a specially crafted application. The security update addresses the vulnerability by correcting how the Windows RDP server initializes memory.

A denial of service vulnerability exists in Remote Desktop Protocol (RDP) when an attacker connects to the target system using RDP and sends specially crafted requests. An attacker who successfully exploited this vulnerability could cause the RDP service on the target system to stop responding. To exploit this vulnerability, an attacker would need to run a specially crafted application against a server which provides Remote Desktop Protocol (RDP) services. The update addresses the vulnerability by correcting how RDP handles connection requests.

A remote code execution vulnerability exists in Remote Desktop Services – formerly known as Terminal Services – when an unauthenticated attacker connects to the target system using RDP and sends specially crafted requests. This vulnerability is pre-authentication and requires no user interaction. An attacker who successfully exploited this vulnerability could execute arbitrary code on the target system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would need to send a specially crafted request to the target systems Remote Desktop Service via RDP. The update addresses the vulnerability by correcting how Remote Desktop Services handles connection requests.

A spoofing vulnerability exists in the way Microsoft Outlook iOS software parses specifically crafted email messages. An authenticated attacker could exploit the vulnerability by sending a specially crafted email message to a victim. The attacker who successfully exploited this vulnerability could then perform cross-site scripting attacks on the affected systems and run scripts in the security context of the current user. The security update addresses the vulnerability by correcting how Outlook iOS parses specially crafted email messages.

A memory corruption vulnerability exists in the Windows Server DHCP service when an attacker sends specially crafted packets to a DHCP server. An attacker who successfully exploited the vulnerability could run arbitrary code on the DHCP server. To exploit the vulnerability, an attacker could send a specially crafted packet to a DHCP server. The security update addresses the vulnerability by correcting how DHCP servers handle network packets.

A memory corruption vulnerability exists in the Windows Server DHCP service when processing specially crafted packets. An attacker who successfully exploited the vulnerability could cause the DHCP server service to stop responding. To exploit the vulnerability, a remote unauthenticated attacker could send a specially crafted packet to an affected DHCP server. The security update addresses the vulnerability by correcting how DHCP servers handle network packets.

An elevation of privilege vulnerability exists in Git for Visual Studio when it improperly parses configuration files. An attacker who successfully exploited the vulnerability could execute code in the context of another local user. To exploit the vulnerability, an authenticated attacker would need to modify Git configuration files on a system prior to a full installation of the application. The attacker would then need to convince another user on the system to execute specific Git commands. The update addresses the issue by changing the permissions required to edit configuration files.

A memory corruption vulnerability exists in the Windows Server DHCP service when an attacker sends specially crafted packets to a DHCP failover server. An attacker who successfully exploited the vulnerability could cause the DHCP service to become nonresponsive. To exploit the vulnerability, an attacker could send a specially crafted packet to a DHCP server. However, the DHCP server must be set to failover mode for the attack to succeed. The security update addresses the vulnerability by correcting how DHCP failover servers handle network packets.

A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. The file could then take actions on behalf of the logged-on user with the same permissions as the current user. To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Word software. Two possible email attack scenarios exist for this vulnerability: With the first email attack scenario, an attacker could send a specially crafted email message to the user and wait for the user to click on the message. When the message renders via Microsoft Word in the Outlook Preview Pane, an attack could be triggered. With the second scenario, an attacker could attach a specially crafted file to an email, send it to a user, and convince them to open it. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or other message, and then convince the user to open the specially crafted file. The security update addresses the vulnerability by correcting how Microsoft Word handles files in memory. For users who view their emails in Outlook, the Preview Pane attack vector can be mitigated by disabling this feature. The following registry keys can be set to disable the Preview Pane in Outlook on Windows, either via manual editing of the registry or by modifying Group Policy. Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Outlook 2010: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options DWORD: DisableReadingPane Value: 1 Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options DWORD: DisableReadingPane Value: 1 Outlook 2016, Outlook 2019, and Office 365 ProPlus: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options DWORD: DisableReadingPane Value: 1

An elevation of privilege vulnerability exists when Microsoft Outlook initiates processing of incoming messages without sufficient validation of the formatting of the messages. An attacker who successfully exploited the vulnerability could attempt to force Outlook to load a local or remote message store (over SMB). To exploit the vulnerability, the attacker could send a specially crafted email to a victim. Outlook would then attempt to open a pre-configured message store contained in the email upon receipt of the email. This update addresses the vulnerability by ensuring Office fully validates incoming email formatting before processing message content.

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.

An information disclosure vulnerability exists in the way Microsoft SharePoint handles session objects. An authenticated attacker who successfully exploited the vulnerability could hijack the session of another user. To exploit this vulnerability, the attacker could run a specially crafted application. The security update corrects how SharePoint handles session objects to prevent user session hijacking.

A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. The file could then take actions on behalf of the logged-on user with the same permissions as the current user. To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Word software. Two possible email attack scenarios exist for this vulnerability: • With the first email attack scenario, an attacker could send a specially crafted email message to the user and wait for the user to click on the message. When the message renders via Microsoft Word in the Outlook Preview Pane, an attack could be triggered. • With the second scenario, an attacker could attach a specially crafted file to an email, send it to a user, and convince them to open it. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or other message, and then convince the user to open the specially crafted file. The security update addresses the vulnerability by correcting how Microsoft Word handles files in memory. For users who view their emails in Outlook, the Preview Pane attack vector can be mitigated by disabling this feature. The following registry keys can be set to disable the Preview Pane in Outlook on Windows, either via manual editing of the registry or by modifying Group Policy. Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Outlook 2010: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options DWORD: DisableReadingPane Value: 1 Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options DWORD: DisableReadingPane Value: 1 Outlook 2016, Outlook 2019, and Office 365 ProPlus: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options DWORD: DisableReadingPane Value: 1

A remote code execution vulnerability exists in Microsoft Outlook software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user. To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Outlook software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or Instant Messenger message, and then convince the user to open the specially crafted file. Note that the Preview Pane is not an attack vector for this vulnerability. The security update addresses the vulnerability by correcting how Microsoft Outlook handles files in memory.