Microsoft Windows 7 Service Pack 1

Microsoft is investigating reports of a remote code execution vulnerability in MSHTML that affects Microsoft Windows. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability by using specially-crafted Microsoft Office documents.

An attacker could craft a malicious ActiveX control to be used by a Microsoft Office document that hosts the browser rendering engine. The attacker would then have to convince the user to open the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

Microsoft Defender Antivirus and Microsoft Defender for Endpoint both provide detection and protections for the known vulnerability. Customers should keep antimalware products up to date. Customers who utilize automatic updates do not need to take additional action. Enterprise customers who manage updates should select the detection build 1.349.22.0 or newer and deploy it across their environments. Microsoft Defender for Endpoint alerts will be displayed as: “Suspicious Cpl File Execution”.

Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs.

Please see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.

UPDATE September 14, 2021: Microsoft has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. Please see the FAQ for important information about which updates are applicable to your system.

A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

UPDATE August 10, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. This security update changes the Point and Print default behavior; please see KB5005652.

A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

UPDATE July 7, 2021: The security update for Windows Server 2012, Windows Server 2016 and Windows 10, Version 1607 have been released. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability.

In addition to installing the updates, in order to secure your system, you must confirm that the following registry settings are set to 0 (zero) or are not defined (Note: These registry keys do not exist by default, and therefore are already at the secure setting.), also that your Group Policy setting are correct (see FAQ):

• HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint
• NoWarningNoElevationOnInstall = 0 (DWORD) or not defined (default setting)
• UpdatePromptSettings = 0 (DWORD) or not defined (default setting)

Having NoWarningNoElevationOnInstall set to 1 makes your system vulnerable by design.

UPDATE July 6, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. See also KB5005010: Restricting installation of new printer drivers after applying the July 6, 2021 updates.

Note that the security updates released on and after July 6, 2021 contain protections for CVE-2021-1675 and the additional remote code execution exploit in the Windows Print Spooler service known as “PrintNightmare”, documented in CVE-2021-34527.

An elevation of privilege vulnerability exists in Microsoft Windows when Folder redirection has been enabled via Group Policy. When folder redirection file server is co-located with Terminal server, an attacker who successfully exploited the vulnerability would be able to begin redirecting another user's personal data to a created folder.

To exploit the vulnerability, an attacker can create a new folder under the Folder Redirection root path and create a junction on a newly created User folder. When the new user logs in, Folder Redirection would start redirecting to the folder and copying personal data.

This elevation of privilege vulnerability can only be addressed by reconfiguring Folder Redirection with Offline files and restricting permissions, and NOT via a security update for affected Windows Servers. See the FAQ section of this CVE for configuration guidance.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

A denial of service vulnerability exists in Microsoft Outlook software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could cause a remote denial of service against a system.

Exploitation of the vulnerability requires that a specially crafted email be sent to a vulnerable Outlook server.

The security update addresses the vulnerability by correcting how Microsoft Outlook handles objects in memory.

An elevation of privilege vulnerability exists when Group Policy improperly checks access. An attacker who successfully exploited this vulnerability could run processes in an elevated context.

To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system.

The security update addresses the vulnerability by correcting how Group Policy checks access.

An elevation of privilege vulnerability exists when the Windows User Profile Service (ProfSvc) improperly handles junction points. An attacker who successfully exploited this vulnerability could delete files and folders in an elevated context.

To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and delete files or folders of their choosing.

The security update addresses the vulnerability by correcting how the Windows User Profile Service handles junction points.

An information disclosure vulnerability exists when the .NET Framework improperly handles objects in memory. An attacker who successfully exploited the vulnerability could disclose contents of an affected system's memory.

To exploit the vulnerability, an authenticated attacker would need to run a specially crafted application.

The update addresses the vulnerability by correcting how the .NET Framework handles objects in memory.

An elevation of privilege vulnerability exists when Windows improperly handles COM object creation. An attacker who successfully exploited the vulnerability could run arbitrary code with elevated privileges.

To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.

The update addresses the vulnerability by correcting how the Windows COM Server creates COM objects.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

A security feature bypass vulnerability exists in Microsoft Word software when it fails to properly handle .LNK files. 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 Word 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.

The security update addresses the vulnerability by correcting how Microsoft Word handles these files.

A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system.

An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file.

The update addresses the vulnerability by correcting the way the Windows Jet Database Engine handles objects in memory.

A spoofing vulnerability exists when Windows incorrectly validates file signatures. An attacker who successfully exploited this vulnerability could bypass security features and load improperly signed files.

In an attack scenario, an attacker could bypass security features intended to prevent improperly signed files from being loaded.

The update addresses the vulnerability by correcting how Windows validates file signatures.

A remote code execution vulnerability exists in the way that Microsoft Graphics Components handle objects in memory. An attacker who successfully exploited the vulnerability could execute arbitrary code on a target system.

To exploit the vulnerability, a user would have to open a specially crafted file.

The security update addresses the vulnerability by correcting how Microsoft Graphics Components handle objects in memory.

An elevation of privilege vulnerability exists when the Windows Application Compatibility Client Library improperly handles registry operations. An attacker who successfully exploited this vulnerability could gain elevated privileges.

To exploit the vulnerability, an attacker would first need code execution on a victim system. An attacker could then run a specially crafted application.

The security update addresses the vulnerability by ensuring the Windows Application Compatibility Client Library properly handles registry operations.

An elevation of privilege vulnerability exists when Windows improperly handles COM object creation. An attacker who successfully exploited the vulnerability could run arbitrary code with elevated privileges.

To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.

The update addresses the vulnerability by correcting how the Windows COM Server creates COM objects.

An information disclosure vulnerability exists in the way that the Windows Graphics Device Interface Plus (GDI+) handles objects in memory, allowing an attacker to retrieve information from a targeted system. By itself, the information disclosure does not allow arbitrary code execution; however, it could allow arbitrary code to be run if the attacker uses it in combination with another vulnerability.

To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted application.

The security update addresses the vulnerability by correcting how GDI+ handles memory addresses.

An elevation of privilege vulnerability exists when the Windows Backup Service improperly handles file operations.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Backup Service handles file operations.

A remote code execution vulnerability exists in the way that the Windows Graphics Device Interface (GDI) handles objects in the memory. An attacker who successfully exploited this vulnerability could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

There are multiple ways an attacker could exploit the vulnerability:

• In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability and then convince users to view the website. An attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to open an email attachment or click a link in an email or instant message.
• In a file-sharing attack scenario, an attacker could provide a specially crafted document file that is designed to exploit the vulnerability, and then convince users to open the document file.

The security update addresses the vulnerability by correcting the way that the Windows GDI handles objects in the memory.

An elevation of privilege vulnerability exists in the Windows Installer when the Windows Installer fails to properly sanitize input leading to an insecure library loading behavior.

A locally authenticated attacker could run arbitrary code with elevated system privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

The security update addresses the vulnerability by correcting the input sanitization error to preclude unintended elevation.

An elevation of privilege vulnerability exists when the Windows Event System improperly handles objects in memory.

To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges.

The security update addresses the vulnerability by correcting how the Windows Event System handles objects in memory.

An elevation of privilege vulnerability exists in the way that the Windows Network Connections Service handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.

To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application.

The security update addresses the vulnerability by ensuring the Windows Network Connections Service properly handles objects in memory.

A denial of service vulnerability exists in Windows Remote Desktop Service 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 Remote Desktop 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 Service.

The update addresses the vulnerability by correcting how Remote Desktop Service handles connection requests.

A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.

The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.

A remote code execution vulnerability exists when Windows Media Audio Decoder improperly handles objects. An attacker who successfully exploited the vulnerability could take control of an affected system.

There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document, or by convincing a user to visit a malicious webpage.

The security update addresses the vulnerability by correcting how Windows Media Audio Decoder handles objects.

An elevation of privilege vulnerability exists in the way that the Windows Function Discovery Service handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.

To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application.

The security update addresses the vulnerability by ensuring the Windows Function Discovery Service properly handles objects in memory.

An elevation of privilege vulnerability exists in the way that fdSSDP.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.

To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application.

The security update addresses the vulnerability by ensuring the ssdpsrv.dll properly handles objects in memory.

A remote code execution vulnerability exists in the way that the Windows Graphics Device Interface (GDI) handles objects in the memory. An attacker who successfully exploited this vulnerability could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

There are multiple ways an attacker could exploit the vulnerability:

• In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability and then convince users to view the website. An attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to open an email attachment or click a link in an email or instant message.
• In a file-sharing attack scenario, an attacker could provide a specially crafted document file that is designed to exploit the vulnerability, and then convince users to open the document file.

The security update addresses the vulnerability by correcting the way that the Windows GDI handles objects in the memory.

A remote code execution vulnerability exists when Windows improperly handles objects in memory. To exploit the vulnerability an attacker would have to convince a user to run a specially crafted application.

An attacker who successfully exploited this vulnerability could execute arbitrary code and take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

The updates address the vulnerability by correcting how Windows handles objects in memory.

An information disclosure vulnerability exists when the Windows GDI component improperly discloses the contents of its memory. An attacker who successfully exploited the vulnerability could obtain information to further compromise the user’s system.

There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document, or by convincing a user to visit an untrusted webpage.

The security update addresses the vulnerability by correcting how the Windows GDI component handles objects in memory.

An information disclosure vulnerability exists when the win32k component improperly provides kernel information. An attacker who successfully exploited the 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 security update addresses the vulnerability by correcting how win32k handles objects in memory.

An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. 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 first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.

The update addresses this vulnerability by correcting how Win32k handles objects in memory.

An elevation of privilege vulnerability exists when the Windows Common Log File System (CLFS) driver improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run processes in an elevated context.

To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system.

The security update addresses the vulnerability by correcting how CLFS handles objects in memory.

An information disclosure vulnerability exists when the Windows GDI component improperly discloses the contents of its memory. An attacker who successfully exploited the vulnerability could obtain information to further compromise a user’s system.

There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document or by convincing a user to visit an untrusted webpage.

The update addresses the vulnerability by correcting how the Windows GDI component handles objects in memory.

An information disclosure vulnerability exists when the Microsoft Windows Graphics Component improperly handles objects in memory. An attacker who successfully exploited the 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 update addresses the vulnerability by correcting the way in which the Windows Graphics Component handles objects in memory.

An information disclosure vulnerability exists when the Windows GDI component improperly discloses the contents of its memory. An attacker who successfully exploited the vulnerability could obtain information to further compromise a user’s system.

There are multiple ways an attacker could exploit the vulnerability, such as by convincing a user to open a specially crafted document or by convincing a user to visit an untrusted webpage.

The update addresses the vulnerability by correcting how the Windows GDI component handles objects in memory.

A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system.

An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file.

The update addresses the vulnerability by correcting the way the Windows Jet Database Engine handles objects in memory.

An elevation of privilege vulnerability exists in the way that the ssdpsrv.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.

To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application.

The security update addresses the vulnerability by ensuring the ssdpsrv.dll properly handles objects in memory.

A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system.

An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file.

The update addresses the vulnerability by correcting the way the Windows Jet Database Engine handles objects in memory.

A denial of service vulnerability exists when Windows Routing Utilities improperly handles objects in memory. An attacker who successfully exploited the vulnerability could cause a target system to stop responding.

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 cause a target system to stop responding.

The update addresses the vulnerability by correcting how Windows handles objects in memory.

An information disclosure vulnerability exists in the way that the Windows Server DHCP service improperly discloses the contents of its memory.

To exploit the vulnerability, an unauthenticated attacker could send a specially crafted packet to an affected DHCP server. An attacker who successfully exploited this vulnerability could obtain information to further compromise the user’s system.

The security update addresses the vulnerability by correcting how DHCP servers initializes memory.

An elevation of privilege vulnerability exists when Microsoft Windows processes group policy updates. An attacker who successfully exploited this vulnerability could potentially escalate permissions or perform additional privileged actions on the target machine.

To exploit this vulnerability, an attacker would need to launch a man-in-the-middle (MiTM) attack against the traffic passing between a domain controller and the target machine. An attacker could then create a group policy to grant administrator rights to a standard user.

The security update addresses the vulnerability by enforcing Kerberos authentication for certain calls over LDAP.

An elevation of privilege vulnerability exists when the Windows Print Spooler service improperly allows arbitrary writing to the file system. An attacker who successfully exploited this vulnerability could run arbitrary code with elevated system privileges. 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 have to log on to an affected system and run a specially crafted script or application.

The update addresses the vulnerability by correcting how the Windows Print Spooler Component writes to the file system.

An elevation of privilege vulnerability exists in the way that the Wininit.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions.

There are multiple ways an attacker could exploit the vulnerability:

• In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit this vulnerability and then convince a user to view the website. An attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to click a link in an email message or in an Instant Messenger message that takes users to the attacker's website, or by opening an attachment sent through email.

• In a file sharing attack scenario, an attacker could provide a specially crafted document file that is designed to exploit this vulnerability, and then convince a user to open the document file.

The security update addresses the vulnerability by ensuring the Wininit.dll properly handles objects in memory.