KLA11997
Multiple vulnerabilities in Microsoft Browser

Multiple vulnerabilities were found in Microsoft Browser. Malicious users can exploit these vulnerabilities to execute arbitrary code.

Below is a complete list of vulnerabilities:

1. A memory Corruption vulnerability in Internet Explorer can be exploited remotely to execute arbitrary code.
2. A memory Corruption vulnerability in Scripting Engine can be exploited remotely to execute arbitrary code.
3. A memory Corruption vulnerability in Microsoft Browser can be exploited remotely to execute arbitrary code.
4. A memory Corruption vulnerability in Chakra Scripting Engine can be exploited remotely to execute arbitrary code.

Technical details

To address CVE-2020-17052, a Throttling Policy for EWSMaxSubscriptions could be defined and applied to the organization with a value of zero. This will prevent the Exchange server from sending EWS notifications, and prevent client applications which rely upon EWS notifications from functioning normally. Examples of impacted applications include Outlook for Mac, Skype for Business, notification reliant LOB applications, and some iOS native mail clients.

Please see Throttling Policy, for more information.

An example:

New-ThrottlingPolicy -Name AllUsersEWSSubscriptionBlockPolicy -EwsMaxSubscriptions 0 -ThrottlingPolicyScope Organization

A planned update is in development. If you determine that your system is at high risk then you should evaluate the proposed workaround.

After installing the update, you can undo the above action with this command:

Remove-ThrottlingPolicy AllUsersEWSSubscriptionBlockPolicy

Malware exists for this vulnerability. Usually such malware is classified as Exploit. More details.

Internet Explorer 11
ChakraCore
Microsoft Edge (EdgeHTML-based)

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel) and follow additional recommendations for CVE-2020-17052.

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