News Microsoft Zaps 5-Year-Old Defender Bug, Reduces CPU Usage by 75% in Firefox

[Admin]

Defender and Firefox were not best friends, but a major bug affecting their interaction (wasting CPU cycles) has now been fixed.

Microsoft Zaps 5-Year-Old Defender Bug, Reduces CPU Usage by 75% in Firefox : Read more

 

[frogr]

wasn't this "bug"slipped in by Microsoft years ago to slow the Firefox browser and force people to try Microsoft's browsers?

 

[RichardtST]

I wonder if this is the same bug that tried to kill Thunderbird (Mozilla email)? I could hardly read or write an email because of the lag. Adding a virus exclusion to the Thunderbird directory provided instant resolution. But that is not exactly a safe solution, of course. I'll have to try taking the exclusion back out...

 

[hotaru251]

just another reason to use Firefox now and avoid the Chromium browsers.

 

[Integr8d]

"It sends these ‘VirtualProtect’ calls to the antivirus / anti-malware provider to try and keep the browser safe"

When you're on the practice field w/ your son, you don't tell him to 'try AND hit the ball'. You tell him to 'try TO hit the ball'.

You're welcome

 

[SunMaster]

The old saying was «DOS ain’t done till Lotus won’t run».

Microsoft will never change.

And I will probably always cheer for the underdog - I hate monopolies.

 

[randomizer]

wasn't this "bug"slipped in by Microsoft years ago to slow the Firefox browser and force people to try Microsoft's browsers?

It would be pretty silly to slip in a bug affecting anything which make these API calls just to slow down Firefox.

 

[RedBear87]

just another reason to use Firefox now and avoid the Chromium browsers.

I've been using Firefox since version 1.5 back in 2005, honestly I didn't know about this issue and it makes me wonder whether I should really keep sticking Firefox. At this point it mostly boils down to legacy addons and not liking to share my whole browsing history directly with Google's servers... when they blocked most extensions on Android I was already quite disappointed, albeit I've regained most of my extensions with the Nightly Builds since then.

 

[setx]

The solution is obvious, simple and was already available: kill MsMpEng.exe service and related kernel drivers.
If you think you really need an antivirus – just install a decent 3'd party solution.

 

[randomizer]

The solution is obvious, simple and was already available: kill MsMpEng.exe service and related kernel drivers.
If you think you really need an antivirus – just install a decent 3'd party solution.

While the bug raised was about Defender, any AV that follows the same pattern for getting ETW event details could be affected to some degree.

 

[kyzarvs]

It would be pretty silly to slip in a bug affecting anything which make these API calls just to slow down Firefox.

Is it really any different to the not-at-all-twaddle "Something went wrong so we had to reset your default browser preferences" update message?

 

[KyaraM]

I wonder, is that why Firefox had such severe issues a couple years back, that made me use a derivate for a time? It's working much better now, but apparently it can still get better. Looking forward to it.

 

[randomizer]

Is it really any different to the not-at-all-twaddle "Something went wrong so we had to reset your default browser preferences" update message?

Er... yes.

 

[kyzarvs]

Er... yes.

Could you expand? Both are erroneous symptoms employed by the O/S developer to change your chosen app preferences. One slowed FF down and the other downright swapped it out with Edge.

 

[einheriar]

I use linux, never have that problem there..

 

[randomizer]

Could you expand?

If you want details, read the (recent) comments in the bug report linked in the article.

Both are erroneous symptoms employed by the O/S developer to change your chosen app preferences.

Your speculation is absurd. It is unfathomable that Microsoft would deliberately create CPU overhead for everything which generates ETW events listened to by Defender just to slow down a browser that almost nobody uses.

 

[KyaraM]

a browser that almost nobody uses.

Now that's news to me... been using Firefox since forever. Even this post was written in Firefox.

 

[voyteck]

wasn't this "bug"slipped in by Microsoft years ago to slow the Firefox browser and force people to try Microsoft's browsers?

Have you read the article? Quote:

Mozilla devs acknowledge that “We should try to reduce the number of events that Firefox generates, which will reduce the CPU usage from [all] AV software.” With this in mind, it is also worth noting that other AV solutions, like those from Norton, will also consume a lot of CPU time due to the numerous (7x) Firefox calls for monitoring VirtualProtect. Thus, any program that calls VirtualProtect will benefit from Microsoft’s new MsMpEng.exe, not just Firefox.

 

[eric79xxl]

What is the patch that this article is talking about? Is there a specific KB?

 

[flytrap23]

just another reason to use Firefox now and avoid the Chromium browsers.

No it's not.

 

[jeremyj_83]

just install a decent 3'd party solution

Defender is a very good AV solution. Since it is integrated into the OS, it is faster, uses less resources, and doesn't open up other security holes found on 3rd party solutions. Does it cover things like VPN, no, so if you need that then you need to go 3rd party. However, if you just need AV protection it is already one of the best you can get and it is free.

 

[hotaru251]

No it's not.

it is.
Google likes to tout how "chrome is the best thing" and it was...a decade ago.

now-a-days chrome (and its chromium children) are nothing special compared to other browsers & chrome still has its drug addiction to your ram. (has gotten better but still there)

 

[Deleted member 14196]

Believe it or not, I prefer Microsoft implementation of chrome browser. And the fact that it does everything we needed to do at work. It’s our de facto.

works well with all out tools

 

[setx]

Defender is a very good AV solution. Since it is integrated into the OS, it is faster, uses less resources, and doesn't open up other security holes found on 3rd party solutions. Does it cover things like VPN, no, so if you need that then you need to go 3rd party. However, if you just need AV protection it is already one of the best you can get and it is free.

Defender is very far from "good AV solution". Because if you just don't need the AV protection it's the worst one.
First of all it's shown down the user throat without asking if the user wants it or not. Then it's quite hard to disable it: there is no official way to uninstall it. In Win10 it at least honors the group policy that disables it so you can clean the system after that, but in Win11 the policy is ignored and you need to kill the kernel drivers from some other system.

 

[kerberos_20]

I wonder if this is the same bug that tried to kill Thunderbird (Mozilla email)? I could hardly read or write an email because of the lag. Adding a virus exclusion to the Thunderbird directory provided instant resolution. But that is not exactly a safe solution, of course. I'll have to try taking the exclusion back out...

defender used to be junk, back in old win7 days got massive lags in mmorpg sieges with defender, wasted like 80% cpu (6core cpu)