A security feature bypass vulnerability exists in Device Guard that could allow an attacker to inject malicious code into a Windows PowerShell session. An attacker who successfully exploited this vulnerability could inject code into a trusted PowerShell process to bypass the Device Guard Code Integrity policy on the local machine.

To exploit the vulnerability, an attacker would first have to access the local machine, and then inject malicious code into a script that is trusted by the Code Integrity policy. The injected code would then run with the same trust level as the script and bypass the Code Integrity policy.

The update addresses the vulnerability by correcting how PowerShell exposes functions and processes user supplied code.

Information published.

An elevation of privilege vulnerability exists when Microsoft Cortana allows arbitrary website browsing on the lockscreen.

An attacker who successfully exploited the vulnerability could steal browser stored passwords or log on to websites as another user. To exploit the vulnerability, an attacker would require physical access to the console and the system must have Microsoft Cortana assistance enabled.

The security update addresses the vulnerability by preventing Microsoft Cortana from allowing arbitrary website browsing on the lockscreen.

Information published.

A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the Chakra scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists when Internet Explorer improperly validates hyperlinks before loading executable libraries.

An attacker who successfully exploited this vulnerability 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. 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.

An attacker could host a specially crafted website designed to exploit the vulnerability through Internet Explorer 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. However, in all cases an attacker would have no way to force a user to view the attacker-controlled content. Instead, an attacker would have to convince a user to take action, typically by an enticement in an email or instant message, or by getting the user to open an attachment sent through email.

The updates address the vulnerability by correcting how Internet Explorer validates hyperlinks before loading executable libraries.

I am running Interenet Explorer 11 on Windows 7 or Windows Server 2008 R2. Why do I need to install the Security Only update and not the IE Cumulative Update?

The binary affected by this vulnerability is in the code path for Windows 7 and not for Internet Explorer 11. Customers Internet Explorer 11 on Windows 7 or Windows Server 2008 R2 and who normally install the IE Cumulative updates should install the Windows Security Only update to be protected from this vulnerability.

Information published.

Executive Summary

On January 3, 2018, Microsoft released an advisory and security updates for a new class of hardware vulnerabilities involving speculative execution side channels (known as Spectre and Meltdown). Microsoft is aware of a new speculative execution side channel vulnerability known as L1 Terminal Fault (L1TF) which has been assigned multiple CVEs as noted in the following table. This vulnerability affects Intel® Core® processors and Intel® Xeon® processors. For more information, see Intel’s advisory at: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00161.html.

An attacker who has successfully exploited L1TF may be able to read privileged data across trust boundaries. In shared resource environments (such that exist in some cloud services configurations), this vulnerability could allow one virtual machine to improperly access information from another. An attacker would need prior access to the system or the ability to run code on the system to leverage this vulnerability. For a technical description of L1TF please see our Security Research and Defense (SRD) blog.

Microsoft has released several updates to help mitigate this vulnerability. To get all available protections, firmware (microcode) and software updates are required. We have also taken action to secure our cloud services. See the Microsoft cloud customers section for more details.

Microsoft has not received any information to indicate that this vulnerability has been used to attack customers at this time. Microsoft continues to work closely with industry partners, including chip makers, hardware OEMs, and app vendors to protect customers from the speculative execution class of hardware vulnerabilities.

Recommended Actions

1. The best protection is to keep your computers up to date. You can do this by taking advantage of automatic updates. Learn how to turn on automatic updates here.

2. Enterprise customers should:

   1. Review this advisory in detail for guidance by product or service and register for the security notifications mailer to be alerted of content changes to this advisory. See Microsoft Technical Security Notifications.

   2. Inventory the processors in use across the enterprise to determine risk exposure and help inform the required protections for L1TF.

   3. Inventory the use of Virtualization Based Security (VBS) across the enterprise and especially in client systems to help inform the required protections.

   4. Evaluate the risk posed by L1TF to enterprise environments. In general terms, any system that was deemed to need protection for CVE-2017-5715 (Spectre Variant 2, Branch Target Injection) would need protection for L1TF.

3. Verify the status of protection for CVE-2018-3620 using the PowerShell script Get-SpeculationControlSettings. For more information and to obtain the PowerShell script see Understanding Get-SpeculationControlSettings PowerShell script output.

Potential performance impacts

In testing, Microsoft has seen some performance impact with these mitigations depending on the configuration of the system and what mitigations are needed. For most consumer devices, we have not observed a noticeable performance impact after applying the updates.  Customers that use Virtualization Based Security (VBS) or versions of Hyper-V prior to Windows Server 2016 may need to disable Hyper-Threading to fully address the risk from L1 Terminal Fault (L1TF), resulting in performance degradation. Performance impact will vary by hardware and the workloads running on the system. As the most common device and server configuration is to have Hyper-Threading enabled, the performance impact will depend on whether the user or administrator takes the action to disable Hyper-Threading on the system. As noted earlier, Windows Server 2016 provides an option to enable the Hyper-V Core Scheduler which mitigates the L1TF attack vector while allowing Hyper-Threading to remain enabled, resulting in a minimal performance impact For information on performance impact by Intel, please see: www.intel.com/securityfirst.

Advisory Details

Vulnerabilities Description

Speculative execution side-channel vulnerabilities such as L1 Terminal Fault (L1TF) can be used to read the content of memory across a trusted boundary and if exploited, can lead to information disclosure. There are multiple vectors by which an attacker could trigger the vulnerabilities depending on the configured environment. For a detailed view of affected scenarios and Microsoft’s approach to mitigating L1TF please see our Security Research and Defense (SRD) blog. The following table summarizes the potential relevance of L1TF to various attack scenarios and the applicable CVE:

Microsoft cloud customers

Microsoft has deployed mitigations across our cloud services which reinforce the isolation between customers.

Customers who host untrusted code inside their applications should see Guidance for mitigating speculative execution side-channel vulnerabilities in Azure.

Microsoft Windows client customers

Customers using Windows client operating systems on systems with affected Intel processors may need to apply both firmware (Microcode) and software updates, depending on how the system is configured. However, most devices running Windows client operating systems will only need Windows software updates for protection. We have not observed performance degradation from these changes. The following table outlines the requirements for full protection for each CVE:

* Protection for CVE-2018-3620 builds on the protection for CVE-2017-5354 (Meltdown) which is enabled by default on client. Customers that have disabled the protection for CVE-2017-5354 must re-enable it to gain protection for CVE-2018-3620.

** The required microcode is the same microcode that addresses CVE-2018-3639 and CVE-2018-3640.

Customers using Hyper-V or features that rely on Virtualization Based Security (VBS) may need to take additional action to be fully protected:

1. Installation of Windows Security updates (See the Affected Products table in this advisory).
2. Installation of firmware updates provided by the device’s OEM.
3. Disabling Hyper-Threading (See FAQ #1). Note: Disabling Hyper-Threading can affect system performance. Please see Intel’s guidance at www.intel.com/securityfirst for more information.

Windows Virtualization Based Security (VBS) is foundational to Windows 10 security. All VBS features including Hypervisor-enforced Code Integrity (HVCI) and VBS enclaves depend on confidentiality to maintain a strong security boundary. The L1TF vulnerability introduces risk that the confidentiality of VBS secrets could be compromised via a side-channel attack when Hyper-Threading (HT) is enabled, weakening the security boundary provided by VBS. Even with this increased risk, VBS still provides valuable security benefits and mitigates a range of attacks with HT enabled. Hence, we recommend that VBS continue to be used on HT-enabled systems. Customers who want to eliminate the potential risk of the L1TF vulnerability on the confidentiality of VBS should consider disabling HT to mitigate this additional risk.

Windows client operating system users who are using Hyper-V for the security guarantees provided by VM isolation should disable HT to protect against L1TF.

Microsoft Windows Server customers

Customers using Windows Server operating systems may need to apply both firmware (microcode) and software updates, depending on how the system is configured. The followoing table outlines the requirements for full protection for each CVE:

* Protection for CVE-2018-3620 builds on the protection for CVE-2017-5354 (Meltdown) which is disabled by default on Windows Server. To obtain protection for CVE-2018-3620, customers must enable the protection for CVE-2017-5354 (See FAQ #2).

** The required microcode is the same microcode that addresses CVE-2018-3639 and CVE-2018-3640.

Detailed guidance on the actions required for Windows Server customers can be found in Microsoft Knowledge Base Article 4457951.

Microsoft Surface customers

Customers using Microsoft Surface and Surface Book products need to follow the guidance for Windows Client outlined on this advisory. See Microsoft Knowledge Base Article 4073065 for more information about affected Surface products and availability of the microcode updates.

Microsoft Hololens customers

Microsoft HoloLens is unaffected by L1TF because it does not use an affected Intel processor.

FAQ

1. How do I disable Hyper-Threading on my device?

The steps necessary to disable Hyper-Threading will differ from OEM to OEM but are generally part of the BIOS or firmware setup and configuration tools.

2. How do I enable the mitigation for CVE-2017-5354 (Meltdown)?

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. You can then restore the registry if a problem occurs. For more information about how to back up and restore the registry, see Microsoft Knowledge Base 322756 How to back up and restore the registry in Windows.

To enable protection for CVE-2017-5315 and CVE 2017-5354:

reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverride /t REG_DWORD /d 0 /f

reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverrideMask /t REG_DWORD /d 3 /f

Restart the computer for the changes to take effect.

3. What is VBS and how do I know if I am using it?

Virtualization Based Security (VBS) uses hardware virtualization features to create and isolate a secure region of memory from the normal operating system and is used by security features such as Device Guard, Application Guard, Credential Guard, and Hypervisor Code Integrity (HVCI). VBS is supported in the following versions of Windows:

• Windows 10 Version 1803
• Windows 10 Version 1709
• Windows 10 Version 1703
• Windows 10 Version 1607
• Windows Server, version 1803
• Windows Server, version 1709
• Windows Server 2016

To determine if VBS is enabled, run MSINFO32.EXE and look for the Virtualization-based Security line item under the System Summary node.

Information published.

A security feature bypass vulnerability exists when Microsoft Edge improperly handles redirect requests. The vulnerability allows Microsoft Edge to bypass Cross-Origin Resource Sharing (CORS) redirect restrictions, and to follow redirect requests that should otherwise be ignored. An attacker who successfully exploited the vulnerability could force the browser to send data that would otherwise be restricted to a destination website of the attacker's choice.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge and then convince a user to view the website. The attacker could also take advantage of compromised websites, and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how affected Microsoft Edge handles redirect requests.

Information published.

An information disclosure vulnerability exists in Microsoft .NET Framework that could allow an attacker to access information in multi-tenant environments. The vulnerability is caused when .NET Framework is used in high-load/high-density network connections where content from one stream can blend into another stream.

To exploit the vulnerability, an attacker who can access one tenant in a high-load/high-density environment could potentially trigger multi-tenanted data exposure from one customer to another.

The security update addresses the vulnerability by correcting the way .NET Framework handles high-load/high-density network connections.

What type of information could be disclosed by this vulnerability?

The type of information that could be disclosed if an attacker successfully exploited this vulnerability is unauthorized file system access - reading from file system.

Information published.

A information disclosure vulnerability exists when WebAudio Library improperly handles audio requests.

An attacker who has successfully exploited this vulnerability might be able to read privileged data across trust boundaries. In browsing scenarios, an attacker could convince a user to visit a malicious site and leverage the vulnerability to obtain privileged information from the browser process, such as sensitive data from other opened tabs. An attacker could also inject malicious code into advertising networks used by trusted sites or embed malicious code on a compromised, but trusted, site.

The update addresses the vulnerability by correcting how the WebAudio Library handles audio requests.

What type of information could be disclosed by this vulnerability?

The type of information that could be disclosed if an attacker successfully exploited this vulnerability is uninitialized memory.

Information published.

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way the scripting engine handles objects in memory in Microsoft browsers. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website designed to exploit the vulnerability through a Microsoft browser and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the browser rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker 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.

Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Excel. 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) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.

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

Information published.

A remote code execution vulnerability exists in Microsoft PowerPoint software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker 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.

Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Office PowerPoint 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 designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them 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 PowerPoint handles objects in memory.

Information published.

A remote code execution vulnerability exists when Microsoft Edge improperly accesses objects in memory. The vulnerability could corrupt memory in such a way that enables 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, an 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 Edge, and then convince a user to view the website. The attacker could also take advantage of compromised websites and 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 by way of enticement in an email or Instant Messenger message, or by getting them to open an attachment sent through email.

The security update addresses the vulnerability by modifying how Microsoft Edge handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the Chakra scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the Chakra scripting engine handles objects in memory.

Information published.

A spoofing vulnerability exists when Microsoft Edge does not properly parse HTTP content. An attacker who successfully exploited this vulnerability could trick a user by redirecting the user to a specially crafted website. The specially crafted website could either spoof content or serve as a pivot to chain an attack with other vulnerabilities in web services.

To exploit the vulnerability, the user must click a specially crafted URL. In an email attack scenario, an attacker could send an email message containing the specially crafted URL to the user in an attempt to convince the user to click it.

In a web-based attack scenario, an attacker could host a specially crafted website designed to appear as a legitimate website to the user. However, the attacker would have no way to force the user to visit the specially crafted website. The attacker would have to convince the user to visit the specially crafted website, typically by way of enticement in an email or instant message, and then convince the user to interact with content on the website.

The update addresses the vulnerability by correcting how Microsoft Edge parses HTTP responses.

Information published.

A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the Chakra scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way the scripting engine handles objects in memory in Microsoft browsers. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website designed to exploit the vulnerability through a Microsoft browser and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the browser rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

Information published.

A spoofing vulnerability exists when Microsoft Edge improperly handles specific HTML content. An attacker who successfully exploited this vulnerability could trick a user into believing that the user was on a legitimate website. The specially crafted website could either spoof content or serve as a pivot to chain an attack with other vulnerabilities in web services.

To exploit the vulnerability, the user must either browse to a malicious website or be redirected to it. In an email attack scenario, an attacker could send an email message in an attempt to convince the user to click a link to a malicious site.

In a web-based attack scenario, an attacker could host a specially crafted website designed to appear as a legitimate website to the user. However, the attacker would have no way to force the user to visit the specially crafted website. The attacker would have to convince the user to visit the specially crafted website, typically by way of enticement in an email or instant message.

The security update addresses the vulnerability by correcting how Microsoft Edge handles specific HTML content.

Information published.

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability.

The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

Information published.

A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory. The vulnerability could corrupt memory in such a way that an attacker could 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, an attacker who successfully exploited the vulnerability 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.

The security update addresses the vulnerability by modifying how the ChakraCore scripting engine handles objects in memory.

Information published.

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.

What type of information could be disclosed by this vulnerability?

The type of information that could be disclosed if an attacker successfully exploited this vulnerability is memory layout - the vulnerability allows an attacker to collect information that facilitates predicting addressing of the memory.

Information published.

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.

What type of information could be disclosed by this vulnerability?

The type of information that could be disclosed if an attacker successfully exploited this vulnerability is memory layout - the vulnerability allows an attacker to collect information that facilitates predicting addressing of the memory.

Information published.

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.

Information published.