Bug reported Microsoft Defender abnormally jumps in CPU usage in Firefox and Chrome – GIGAZINE

Firefox web browser developmentMozilla FoundationFrom the fault management system you managewith boggsSo, browsing the web with Firefox is Microsoft’s original antivirusMicrosoft Defender(Windows Defender) Increases CPU usage” Error reported.

1441918 – Anti-Malware Service (Windows Defender) Active/Very High CPU when using Firefox
https://bugzilla.mozilla.org/show_bug.cgi?id=1441918#c82

Check system and application behavior and resource usageWindows Performance RecorderWhen using (WPR), when using CPU for “MsMpEng.exe”, the Microsoft Defender executable process file, in Firefox and Chrome jumps abnormally, I work as a Senior Software Engineer at Mozilla FoundationYannis Juglaretreported by mr.

On Windows devices with Microsoft Defender Real-time Protection enabled,VirtualProtectIt seems to be unreasonably high (the CPU usage of MsMpEng.exe is abnormally high).

The information that “VirtualProtect calls are unreasonably high” is said to be information provided by Microsoft. Note that most VirtualProtect calls are caused by the JIT engine, so disabling JIT in both Firefox and Chrome seems to make MsMpEng.exe behave more rationally.

Version 1.1.20200.3 of “mpengine.dll” has been released, which is part of the Microsoft Malware Protection Engine file with bug fixes based on that. By applying this, the CPU usage of MsMpEng.exe is said to be reduced by up to 75%.

1441918 – Anti-Malware Service (Windows Defender) Active/Very High CPU when using Firefox
https://bugzilla.mozilla.org/show_bug.cgi?id=1441918#c91

Below is a graph of CPU usage for Firefox (green) and MsMpEng.exe (red) measured by WPR. The upper graph is before the bug is fixed, and the lower graph is after the bug is fixed. The CPU usage of MsMpEng.exe was significantly reduced after the bug was fixed.

To install version 1.1.20200.3 of mpengine.dll, run a Powershell terminal with administrator privileges, type “Set-MpPreference -EngineUpdatesChannel Beta”, open Windows Update and browse for updates, and check if the new update is to install when it appears.

The way to check mpengine.dll version information is as follows.

Go to “C:\ProgramData\Microsoft\Windows Defender\Definition Updates\;” In Windows Explorer, and open the folder name as there is a list of numbers and letters.

Since there is a file called mpengine.dll in this, right-click on it and click Properties.

You can check the mpengine.dll version information by selecting Product Version in the Details tab.