Multiple Edge Memory Corruption Vulnerabilities
Multiple remote code execution vulnerabilities exist when Microsoft Edge improperly accesses objects in memory.

The vulnerabilities could corrupt memory in a way that enables an attacker to execute arbitrary code in the context of the current user.

An attacker who successfully exploited the vulnerabilities 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 vulnerabilities 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 vulnerabilities.
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 an enticement in an email or instant message, or by getting them to open an email attachment.

The update addresses the vulnerabilities by modifying how Microsoft Edge handles objects in memory.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title

CVE number

Publicly disclosed

Exploited

Microsoft Browser Memory Corruption Vulnerability

CVE-2016-3289

No

No

Microsoft Browser Memory Corruption Vulnerability

CVE-2016-3293

No

No

Microsoft PDF Remote Code Execution Vulnerability

CVE-2016-3319

No

No

Microsoft Browser Memory Corruption Vulnerability

CVE-2016-3322

No

No

Mitigating Factors
Microsoft has not identified any mitigating factors for these vulnerabilities.

Workarounds
Microsoft has not identified any workarounds for these vulnerabilities.
For CVE-2016-3319 only: Remove Microsoft EDGE from the PDF reader default file type association
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
Interactive Method:
Click Start, click Run, type regedit, and then click OK.
Expand HKEY_CLASSES_ROOT, click .EXTENSION, and then click the File menu and select Export.
In the Export Registry File window, type a file name of EXTENSION HKCR file association registry backup.reg and then click Save.

This will create a backup of the registry key in the My Documents folder by default.
Press the Delete key on the keyboard to delete the registry key. When prompted to delete the registry value, click Yes.
Expand HKEY_CURRENT_USER, then Software, then Microsoft, then Windows, then CurrentVersion, then Explorer, then FileExts.
Click .EXTENSION and then click the File menu and select Export.
In the Export Registry File window, type a file name of EXTENSION HKCU file association registry backup.reg and then click Save.

This will create a backup of the registry key in the My Documents folder by default.
Press the Delete key on the keyboard to delete the registry key. When prompted to delete the registry value, click Yes.

Managed Deployment Script:
Make a backup copy of the registry keys using a managed deployment script with the following commands:

Regedit.exe /e EXTENSION_HKCR_registry_backup.reg HKEY_CLASSES_ROOT\.EXTENSION
Regedit.exe /e EXTENSION_HKCU_registry_backup.reg HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.EXTENSION

Next save the following to a file with a .REG extension (e.g., Delete_EXTENSION_file_association.reg):

Windows Registry Editor Version 5.00
[-HKEY_CLASSES_ROOT\.EXTENSION]
[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.EXTENSION]

On the target system, run the registry script created in step 2 using the following command:

Regedit.exe /s Delete_EXTENSION_file_association.reg

Impact of Workaround. PDF documents will no longer open with Microsoft Edge by default.
How to undo the workaround
To undo the workaround, restore the original registry keys that were saved in the initial steps of the workaround.

Scripting Engine Memory Corruption Vulnerability – CVE-2016-3296
A remote code execution vulnerability exists in the way that the Chakra JavaScript engine renders when handling 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.

An attacker could also embed an ActiveX control marked “safe for initialization” in an application or Microsoft Office document that hosts the Edge 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 update addresses the vulnerability by modifying how the Chakra JavaScript scripting engine handles objects in memory.
The following table contains links to the standard entry for the vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title

CVE number

Publicly disclosed

Exploited

Scripting Engine Memory Corruption Vulnerability

CVE-2016-3296

No

No

Mitigating Factors
Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds
Microsoft has not identified any workarounds for this vulnerability.

Multiple Microsoft Edge Information Disclosure Vulnerabilities
Multiple information disclosure vulnerabilities exist when Microsoft Edge improperly handles objects in memory.

An attacker who successfully exploited the vulnerabilities could obtain information to further compromise the user’s system.
To exploit the vulnerabilities, in a web-based attack scenario, an attacker could host a website that is used to attempt to exploit the vulnerabilities.
In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerabilities.
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.

For example, an attacker could trick users into clicking a link that takes them to the attacker’s site.

The update addresses the vulnerabilities by changing how certain functions handle objects in memory.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title

CVE number

Publicly disclosed

Exploited

Microsoft Browser Information Disclosure Vulnerability

CVE-2016-3326

No

No

Microsoft Browser Information Disclosure Vulnerability

CVE-2016-3327

No

No

Mitigating Factors
Microsoft has not identified any mitigating factors for these vulnerabilities.

Workarounds
Microsoft has not identified any workarounds for these vulnerabilities.

Microsoft Edge Information Disclosure Vulnerability – CVE-2016-3329
An information disclosure vulnerability exists when Microsoft Edge improperly handles page content, which could allow an attacker to detect the existence of specific files on the user’s system.

The update addresses the vulnerability by helping to ensure that page content is properly validated in Microsoft Edge.
To exploit the vulnerability, in a web-based attack scenario, an attacker could host a website that is used to attempt to exploit the vulnerability.
In addition, compromised websites and websites that accept or host user-provided content could contain 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.

For example, an attacker could trick users into clicking a link that takes them to the attacker’s site.

The update addresses the vulnerability by changing how certain functions handle objects in memory.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title

CVE number

Publicly disclosed

Exploited

Microsoft Browser Information Disclosure Vulnerability

CVE-2016-3329

No

No

Mitigating Factors
Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds
Microsoft has not identified any workarounds for this vulnerability.

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