MsMpEng.exe conflicting with Firefox plugins

[Diosoth]

This only started this afternoon all of a sudden. MSE's real-time protection process MsMpEng.exe began conflicting with Firefox in a bad way, taking up 100% CPU usage on one of my dual cores whenever I go to a site that uses Flash. This starts when plugin-container.exe kicks in, it seems, as I can go to Google, check gmail and all that fine, but if I go to sites with Flash, the problem starts. I have to go into task manager and manually kill Firefox and the plugins. The browser locks up otherwise.

Disabling real-time protection has stopped the browser issue for the time being. Restarting didn't clear this up.

What's going on? Things worked fine earlier this afternoon- only change was loading up and playing Minecraft for about an hour. I haven't really downloaded much lately and certainly not installed anything, beyond updating Flash today in case that was the issue. I ran scans with MSE, Malwarebytes and Superantispyware, which found nothing. No rogue processes running, no odd startup items.

My suspicion is the definition updates, which were installed at 2:50 PM EST today automatically, which would be around when I started playing MC so not when I had Firefox running. It would certainly explain things if it is the cause but I can't ever be 100% certain by guessing.

 

[Borg 386]

Are you by chance running Malwarebytes Anti Exploit?

I had similar problems to yours. I found that MBAE & Flash don't get along anymore (at least on my system). Flash was going into a endless loop when MBAE was running, constantly re-spawning & eventually freezing FF. Turning off MBAE when I went to a flash site solved the problem.

 

[Diosoth]

I am running that though I'm not 100% certain it's the problem since this only started today after the MSE definition update. Unless the update is conflicting with MBAE and therefore causing issue with Flash as well. I've run them together for some time now with no issue. I'll test it shortly.

edit- shut off MBAE, restarted MSE real-time, Firefox is working fine. Seems today's MSE definition update might be interfering with MBAE somehow which is causing MSE to go into a loop when Firefox loads Flash. I'll monitor it throughout the next few hours, in case.

 

[Borg 386]

I haven't seen it happen on my system today after updating MSE.

I don't know if other people are having that problem with MBAE/Flash player. Thought for a while it might be the new Flash update, but as it turned out, MBAE was causing the problem.

I found it by running Sysinternals Process Explorer. When MBAE was running, I watched Flash Player re-spawn itself for 4 mins straight before I shut off MBAE & then it worked good.

 

[Diosoth]

This is the first time it caused issues with Flash, but I've had several issues with Minecraft- namely, any mod that "dials home" to check for updates and such would sometimes register as an exploit.

Admittedly the free version of MBAE is so neutered in features, I'm not real sure it does much good.