Microsoft Fixes Windows Defender Bug After Five Years of Firefox Slowdowns

[T0@st]

Microsoft's Window Defender engineering team has finally found the time to address a long term bug within its anti-malware software - relating to performance issues with Mozilla's Firefox web browser. User feedback stretching back to five years ago indicates extremely sluggish web surfing experiences, caused by a Windows "Anti-malware Service Executable" occupying significant chunks of CPU utilization (more than 30%). The combination of Firefox and Windows Defender running in parallel would guarantee a butting of (software) heads - up until last week's bug fix. A Microsoft issued update has reduced the "MsMpEng.exe" Defender component's CPU usage by a maximum of 75%.

Microsoft and Mozilla developers have collaborated on addressing the disharmonious relationship between Defender and Firefox. A plucky member of the latter's softwareengineering team has been very transparent about the sluggish browser experience. Yannis Juglaret has provided a string of project updates via Mozilla's Bugzilla tracking system - one of his latest entries provide details about the fix: "You may read online that Defender was making too many calls to VirtualProtect, and that global CPU usage will now go down by 75% when browsing with Firefox. This is absolutely wrong! The impact of this fix is that on all computers that rely on Microsoft Defender's Real-time Protection feature (which is enabled by default in Windows), MsMpEng.exe will consume much less CPU than before when monitoring the dynamic behavior of any program through Event Tracing for Windows (ETW). Nothing less, nothing more."



Juglaret concludes: "For Firefox this is particularly impactful because Firefox (not Defender!) relies a lot on VirtualProtect (which is monitored by MsMpEng.exe through ETW). We expect that on all these computers, MsMpEng.exe will consume around 75% less CPU than it did before when it is monitoring Firefox. Which is really good news."



Microsoft's mpengine.dll version 1.1.20200.4 update was released on April 4, and the results have been pleasing according to user reports on Reddit. Juglaret has suggested that more work can be done by the Microsoft and Mozilla development teams in order to improve general performance: "The latest discoveries in bug 1822650 comment 6 suggest that we can go even further down in CPU usage, with all antivirus software this time, not just Windows Defender."

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[dgianstefani]

Great

 

[ThrashZone]

Hi,
Yeah trying to kill FF usage
Fortunately I've always disabled pretender oops I mean defender so kudo to third party AV's and of course @W1zzard for his scripts

Windows 11 Tweaks for GPU Benchmark

Updated for 24H2 Install without Internet When it prompts you to go online, press Shift+F10 and type "OOBE\BYPASSNRO" (that's an o not a zero at the end). After the automatic reboot you can install without network Install on systems without TPM, UEFI or other requirements...

www.techpowerup.com

rem Disable Windows Defender. For this to work you have to manually disable "Tamper protection"
powershell "if ((Get-ItemProperty -Path 'HKLM:SOFTWARE\Microsoft\Windows Defender\Features').TamperProtection -eq 4) { exit 0; } ; Write-Output 'Windows Defender can not be disabled, Tamper Protection is still active' '' 'Disable Tamper Protection manually, then press OK' | msg /w *"
reg add "HKLM\Software\Policies\Microsoft\Windows Defender\Spynet" /v SpyNetReporting /t REG_DWORD /d 0 /f
reg add "HKLM\Software\Policies\Microsoft\Windows Defender\Spynet" /v SubmitSamplesConsent /t REG_DWORD /d 2 /f
reg add "HKLM\Software\Policies\Microsoft\Windows Defender" /v DisableAntiSpyware /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Policies\Microsoft\Windows Defender" /v DisableRoutinelyTakingAction /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection" /v DisableRealtimeMonitoring /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Explorer" /v SmartScreenEnabled /t REG_SZ /d "Off" /f
reg add "HKLM\Software\Policies\Microsoft\Windows Defender" /v DisableRoutinelyTakingAction /t REG_DWORD /d 1 /f
reg delete HKLM\Software\Microsoft\Windows\CurrentVersion\Run /v SecurityHealth /f

rem Remove Windows Defender Scheduled Tasks
for /f "delims=" %f in ('dir /b "%WINDIR%\System32\Tasks\Microsoft\Windows\Windows Defender"') do schtasks /delete /f /tn "Microsoft\Windows\Windows Defender\%f"

 

[luches]

wasn't there another recent bug with windows defender, where It would flag clean zip and rare files for no reason ? Several forums I check frequently had to put up an announcement clarifying the false positives cause people were panicking hard.

 

[noel_fs]

I dont use any antivirus, just dont open stuff you dont know where its even coming from

 

[Makaveli]

Looks like my system already has this version.

 

[Darmok N Jalad]

I’m honestly a bit surprised it didn’t turn into a legal battle. It’s no secret that MS wants you to use Edge, and has been promoting benefits like faster browsing and better battery life. Well, gee, it’s not hard to beat FF when your own OS has been hobbling the competition for the last 5 years.

That said, I was more a FF user until they adopted that space-wasting and not very attractive UI and took away the ability to revert. I know you can adjust it with CSS tweaks, but that’s not going to win them market share from average users.

 

[ThrashZone]

I’m honestly a bit surprised it didn’t turn into a legal battle. It’s no secret that MS wants you to use Edge, and has been promoting benefits like faster browsing and better battery life. Well, gee, it’s not hard to beat FF when your own OS has been hobbling the competition for the last 5 years.

That said, I was more a FF user until they adopted that space-wasting and not very attractive UI and took away the ability to revert. I know you can adjust it with CSS tweaks, but that’s not going to win them market share from average users.

Hi,
You have an example of what UI you're referring to because everything looks fine to me frankly.

 

[lemonadesoda]

CPU Usage (precise) looks like an interesting tool. What's that + download?

 

[sethmatrix7]

Yea I disabled windows defender in the registry a while ago. When the anti-virus acts like a virus I don’t need it.

 

[Magic Cube]

I’m honestly a bit surprised it didn’t turn into a legal battle. It’s no secret that MS wants you to use Edge, and has been promoting benefits like faster browsing and better battery life. Well, gee, it’s not hard to beat FF when your own OS has been hobbling the competition for the last 5 years.

That said, I was more a FF user until they adopted that space-wasting and not very attractive UI and took away the ability to revert. I know you can adjust it with CSS tweaks, but that’s not going to win them market share from average users.

Yesterday co-worker wanted Google Chrome to his temporary laptop(bookmarks and other stuff). Tried to download Chrome with Edge. Edge crashed everytime when I clicked download button. I just didn't have time to resolve what was causing this, so I had to start IE to download Google Chrome.

 

[natr0n]

I dont use any antivirus, just dont open stuff you dont know where its even coming from

Same.

 

[NoneRain]

I dont use any antivirus, just dont open stuff you dont know where its even coming from

Ever heard about exploits, servers compromise, zero clicks attacks, etc.?

 

[Calenhad]

Oh nice. Now my Firefox use less than 1% CPU instead of a couple %. I have used Firefox as my primary browser for years, never noticed any issues like this honestly. I also just stick with Windows Defender, no need to use any other "scammy" AV out there

 

[Darmok N Jalad]

Hi,
You have an example of what UI you're referring to because everything looks fine to me frankly.

The floating tabs and poor contrast between tabs. Information density is really low, and they take up considerably more vertical space than the previous design. That space matters more on widescreen devices and laptops, where vertical space consumed by padding takes away from the actual content that the browser is made to show. It is easily the most wasteful browser when it comes to UI space. It matters less on displays greater than 1080p, or even 16:10 or 3:2.

 

[Solaris17]

CPU Usage (precise) looks like an interesting tool. What's that + download?

These graphs are generated from the Windows performance analyzer. If you do any Windows management in corporations you may be familiar with the ADK which WPA is part of: https://go.microsoft.com/fwlink/p/?LinkId=526740

Windows Performance Analyzer

Windows Performance Analyzer

learn.microsoft.com

 

[mechtech]

I remember my old p2-350Mhz with win 98se everything ram fast on it at the time. Now it probably wouldn’t be able to play an mp3 everything has become so bloated and intertwined.

maybe devs should only get to use 200 mhz Octo-core. I bet software would get a lot less bloated and more multithreaded lol

 

[InVasMani]

Browsing on a dual core with Mozilla now compared to the last 5 years...

 

[Readlight]

Video is slower on Firefox.
Why with new video card it loses frames on HD60 fps video?

 

[Mussels]

Yesterday co-worker wanted Google Chrome to his temporary laptop(bookmarks and other stuff). Tried to download Chrome with Edge. Edge crashed everytime when I clicked download button. I just didn't have time to resolve what was causing this, so I had to start IE to download Google Chrome.

that sounds like malware, many viruses try to prevent other browsers (and antivirus) being downloaded

 

[Octopuss]

I dont use any antivirus, just dont open stuff you dont know where its even coming from

Oh sweet summer child...

 

[noel_fs]

Ever heard about exploits, servers compromise, zero clicks attacks, etc.?

Oh sweet summer child...

Antivirus are not gonna detect zero day exploits thats why they are zero day, servers compromised are unlikely to happen in services that i use, and for downloads i check everything i download, zero click attacks are based on zero day so same shit, i make sure every piece of software that i use is up to date. Havent had an antivirus in 10 years and not a single password compromised. Im highly unlikely to be a target of anyone capable to attempt any kind of crazy zero day attacks, and if i was i would be taking measures to minimize the damage of a successful attack. So yeah, antivirus are just an excuse for companies to data mine the shit out of people and a way to sell software to technological illiterate people. If you think you are safe because a piece of software in your pc says "protected" you are highly delusional.

 

[Octopuss]

antivirus are just an excuse for companies to data mine the shit out of people

Could you elaborate on your deep metaphysical thoughts for the rest of us simpletons?

 

[Mussels]

Oh sweet summer child...

You can tell the people that never ran windows XP before SP3
Ahh the days of connecting to the internet and instantly having every PC on the network infected and all write-access network shares decimated...


Sure, those companies mine data. But they're mining far less important data than what they protect - don't use the shittier brands and you're fine.

 

[Octopuss]

You're pretty old too, eh? I think I used a firewall from Comodo or something back then. The joy of dealing with 500 popups related to all kinds of fairly bad shit after fresh install is an experience I won't forget

I use ESET Smart Security. I don't believe any data (besides I guess what's needed for improving the software, and even that is opt-outable) is being mined. If they were, someone would have probably find out by now and it would make it into relevant IT circles.