Multiple Microsoft Internet Explorer Memory Corruption Vulnerabilities
Remote code execution vulnerabilities exist when Internet Explorer improperly accesses objects in memory.

The vulnerabilities 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 vulnerabilities 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 vulnerabilities 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 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 an enticement in an email or Instant Messenger message, or by getting them to open an attachment sent through email.

The update addresses the vulnerabilities by modifying how Internet Explorer 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

Internet Explorer Memory Corruption Vulnerability

CVE-2016-3240

No

No

Internet Explorer Memory Corruption Vulnerability

CVE-2016-3241

No

No

Internet Explorer Memory Corruption Vulnerability

CVE-2016-3242

No

No

Internet Explorer Memory Corruption Vulnerability

CVE-2016-3243

No

No

Microsoft Browser Memory Corruption Vulnerability

CVE-2016-3264

No

No

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

Workarounds
Microsoft has not identified any workarounds for these vulnerabilities.

FAQ
I am running Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, or Windows Server 2012 R2.

Does this mitigate these vulnerabilities?
 Yes.

By default, Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration.

Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted web content on a server.

This is a mitigating factor for websites that you have not added to the Internet Explorer Trusted sites zone.
Can EMET help mitigate attacks that attempt to exploit these vulnerabilities? Yes.

The Enhanced Mitigation Experience Toolkit (EMET) enables users to manage security mitigation technologies that help make it more difficult for attackers to exploit memory corruption vulnerabilities in a given piece of software.

EMET can help mitigate attacks that attempt to exploit these vulnerabilities in Internet Explorer on systems where EMET is installed and configured to work with Internet Explorer.
For more information about EMET, see the Enhanced Mitigation Experience Toolkit.

Internet Explorer Security Feature Bypass Vulnerability – CVE-2016-3245
A restricted ports security feature bypass vulnerability exists for Internet Explorer.

An attacker could take advantage of the vulnerability to trick a user into connecting to a remote system.
To exploit the vulnerability, an attacker would have to either convince a user to visit a malicious website or inject malicious code into a compromised website.

The update addresses the vulnerability by correcting how Internet Explorer validates URLs for restricted ports.
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

Internet Explorer Security Feature Bypass Vulnerability

CVE-2016-3245

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 Scripting Engine Memory Corruption Vulnerabilities
Multiple remote code execution vulnerabilities exist in the way that the JScript 9 and VBScript engines render when handling objects in memory in Internet Explorer.

The vulnerabilities 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 vulnerabilities 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 vulnerabilities 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 vulnerabilities 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 vulnerabilities.

The update addresses the vulnerabilities by modifying how the JScript 9 and VBScript scripting engines 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

Scripting Engine Memory Corruption Vulnerability

CVE-2016-3204

No

No

Scripting Engine Memory Corruption Vulnerability

CVE-2016-3248

No

No

Scripting Engine Memory Corruption Vulnerability

CVE-2016-3259

No

No

Scripting Engine Memory Corruption Vulnerability

CVE-2016-3260

No

No

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

Workarounds
The following workaround may be helpful in your situation:
Restrict access to VBScript.dll and JScript.dll
For 32-bit systems, enter the following command at an administrative command prompt:

takeown /f %windir%\system32\vbscript.dll
cacls %windir%\system32\vbscript.dll /E /P everyone:N
cacls %windir%\system32\jscript.dll /E /P everyone:N

For 64-bit systems, enter the following command at an administrative command prompt:

takeown /f %windir%\syswow64\vbscript.dll
cacls %windir%\syswow64\vbscript.dll /E /P everyone:N
cacls %windir%\syswow64\jscript.dll /E /P everyone:N

Impact of Workaround. Websites that use VBScript or JScript may not work properly.
How to undo the workaround.
For 32-bit systems, enter the following command at an administrative command prompt:

cacls %windir%\system32\vbscript.dll /E /R everyone
cacls %windir%\system32\jscript.dll /E /R everyone

For 64-bit systems, enter the following command at an administrative command prompt:

cacls %windir%\syswow64\vbscript.dll /E /R everyone
cacls %windir%\syswow64\jscript.dll /E /R everyone

Multiple Internet Explorer Information Disclosure Vulnerabilities
Information disclosure vulnerabilities exist when the Microsoft Browser 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

Internet Explorer Information Disclosure Vulnerability

CVE-2016-3261

No

No

Microsoft Browser Information Disclosure Vulnerability

CVE-2016-3277

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 Browser Information Disclosure Vulnerability – CVE-2016-3273
An information disclosure vulnerability exists when the Microsoft Browser XSS Filter does not properly validate content under specific conditions.

An attacker who exploited the vulnerability could run arbitrary JavaScript that could lead to an information disclosure.
In a web-based attack scenario, an attacker could host a website in an attempt to exploit this vulnerability.
In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability.
However, in all cases 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 the user to the attacker’s site.

The update addresses the vulnerability by correcting how the Microsoft Browser XSS Filter validates content.
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-2016-3273

No

No

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

Workarounds
Microsoft has not identified any workarounds for this vulnerability.

Microsoft Browser Spoofing Vulnerability – CVE-2016-3274
A spoofing vulnerability exists when a Microsoft browser 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 Messenger message, and then convince the user to interact with content on the website.

The update addresses the vulnerability by correcting how the Microsoft browser parses HTTP responses.
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 Spoofing Vulnerability

CVE-2016-3274

No

No

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

Workarounds
Microsoft has not identified any workarounds for this vulnerability.

Microsoft Browser Spoofing Vulnerability – CVE-2016-3276
A spoofing vulnerability exists when the Microsoft Browser in reader mode does not properly parse HTML content.

An attacker who successfully exploited this vulnerability could trick a user by redirecting them to a specially crafted website.

The specially crafted website could 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 Messenger message, and then convince the user to interact with content on the website.

The update addresses the vulnerability by correcting how the Microsoft Browser parses HTML.
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 Spoofing Vulnerability

CVE-2016-3276

No

No

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

Workarounds
Microsoft has not identified any workarounds for this vulnerability.

Leave a Reply