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kernel security check failure cause by MWAC.sys

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I was just minding my own business, not browsing the internet, just letting my system idle last night when I looked over at my system and a Kernel_Security_Check_Failure BSOD was displaying onscreen. I have my system set to make dumps, for analysis using Windbg. according to the results shown the cause was MWAC.sys


ERROR_CODE: (NTSTATUS) 0xc0000409 - The system detected an overrun of a stack-based buffer in this application. This overrun could potentially allow a malicious user to gain control of this application.

SYMBOL_NAME:  mwac+15bb3


IMAGE_NAME:  mwac.sys

STACK_COMMAND:  .thread ; .cxr ; kb


FAILURE_BUCKET_ID:  0x139_3_CORRUPT_LIST_ENTRY_mwac!unknown_function

OS_VERSION:  10.0.19041.1

BUILDLAB_STR:  vb_release


OSNAME:  Windows 10

FAILURE_ID_HASH:  {b7ff9ef7-2db3-57c8-afc6-0256eccfd112}

Followup:     MachineOwner


I am unable to upload the machine.dmp due to it's size (16 Gb's) and my slow 1mbps upload speed, but i  have attached the entire output from the debugger attached to this message as a text file. if there are additional winbbg commands you wish me too enter, please let me know and i will post the results.

memory.dmp analysis.txt

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  • Staff

***This is an automated reply***


Thanks for posting in the Malwarebytes for Windows Help forum.

If you are having technical issues with our Windows product, please do the following:

Malwarebytes Support Tool - Advanced Options

This feature is designed for the following reasons:

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Thank you for reporting this incident, and I am sorry that it occurred.  I will be sure to report this issue to the team and a member of the staff will likely take a look at the analysis and dumps you provided, so thank you for gathering all of that information for us.

In the meantime, your logs indicate that you are running both Norton and ESET together.  That may be what caused the issue, and running 2 AVs together is not a good idea.  If you have already removed one of the products, the logs are showing traces so you should run the AV's dedicated uninstall utility to remove any remnants.

Let me know which of the two products you wish to remove and I can provide a link to their removal tool to get it cleaned up if needed.


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i saww that when i looked at the logs.... this is wrong. while norton security came with my system it has been uninstalled since day 1 and that was over a year ago. I ran the norton removal software once again too make sure it was really gone. should i post another set of the malwarebytes logs?


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Yes, please do, just to make sure.  It's possible that it is just showing Norton because it is still registered with Security Center, however it is odd that it reports it as being enabled.  It might be that Security Center's data is corrupted somehow.

In the meantime, I've asked that a member of the staff take a look at your crash dumps in case the Devs need them.

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i ran the Malwarebytes support utility once again, and it still lists norton security! as far as i can tell, there is no trace of Norton security left on my system. there are no more left over directories, no more obvious registry files. even the setup file for re-installing the software that was put on the machine by the systems manufacturer has been removed. I don't know why the logs are saying that it is still installed when it isn't. there must be some trace buried deep with in the registry or something.  as per your last post, how would I clear out the Norton entry in security center?

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Security Center is controlled through WMI.  It stores its data within an XML file as I recall, which explains why you wouldn't find any folders or registry entries.  I spoke with a member of Support and he agreed to take a look when he has a chance, and he believes he has a tool to correct the Security Center/Norton issue.

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  • Root Admin

The computer has some odd things going on such as most of your tasks are without a path, very odd. You have some other program crashes such as some Nvidia video card processes.

Please restart the computer. Then temporarily uninstall ESET antivirus and reboot again.

Then temporarily exit out of Malwarebytes and run FRST again. Make sure you place a check mark on the Additions.txt check box and attach back both logs.


Please download Farbar Recovery Scan Tool and save it to your desktop.

Note: You need to run the version compatible with your system.
You can check here if you're not sure if your computer is 32-bit or 64-bit

  • Double-click to run it. When the tool opens click Yes to disclaimer.
  • Press the Scan button.
  • It will make a log (FRST.txt) in the same directory the tool is run. Please attach it to your reply.
  • The first time the tool is run, it also makes another log (Addition.txt). Please attach it to your reply as well.

Thank you



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as much as i like to have system restore enabled, i don't have the drive space for it. when my free drive space dips below 100gb the system begins to slow down. and currently i have 91gb's free on drive C:. i realize thiss is not a wise choice t leave it disabled, but i don't really have a choice. the system came with an itty bitty 256 gb ssd. I have alrady moved as much of the data as windows will allow to other drives. maybe if i moved my office installation too i might free up more space....but my user profile already has portions redirected too a bigger drive. i can also try too see if there is anythiing else that i can apply ntfs compression to on the drive.

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i moved some store app to D:\ and uninstalled some others, I also ran disk cleanup - deliberately unchecking anything that had to do with logs and dumps. my drive space is now sitting at 116 Gb's so I have turned system restore back on for now. to insure that system restore doesn't cause my free space to drop below 100Gb's i have set the size limit to 16gb's i know that level is probably to little, but i don't havemuch choice atm. I have uninstalled ESSP and rebooted and turned off MBAM. I rand FRST according to instructions. logs are attached to this message. i looked at the logs myself since you mentioned tasks with no file paths, and i looked in the task scheduler, but could not find and tasks with out paths. I did look in the registery, and found the entries mentioned in the log, but I have no idea what they are for. perhaps left over entries from previous versions of windows? i also noticed that the log said i had group policy configured, but it could not tell me what was active. I have group policy disabled on this machine. perhaps frst is not able to tell? there is definitly something hinky with the security center, as you will see when you look at my logs

Addition.txt FRST.txt

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  • Root Admin

Great job. Okay, the following fix will remove all those bogus scheduled tasks and remove policy settings as well as general clean up for you.

Make sure you exit out of Malwarebytes when running the following fix.


Please download the attached fixlist.txt file and save it to the Desktop or location where you ran FRST from.
NOTE. It's important that both files, FRST or FRST64, and fixlist.txt are in the same location or the fix will not work.

Please make sure you disable any real time antivirus or security software before running this script. Once completed make sure you re-enable it.

NOTICE: This script was written specifically for this user, for use on this particular machine. Running this on another machine may cause damage to your operating system that cannot be undone.

Run FRST or FRST64 and press the Fix button just once and wait.
If the tool needs a restart please make sure you let the system restart normally and let the tool complete its run after restart.
The tool will make a log on the Desktop (Fixlog.txt) or wherever you ran FRST from. Please attach or post it to your next reply.

Note: If the tool warned you about an outdated version please download and run the updated version.

NOTE-1:  This fix will run a scan to check that all Microsoft operating system files are valid and not corrupt and attempt to correct any invalid files. It will also run a disk check on the restart to ensure disk integrity. Depending on the speed of your computer this fix may take 30 minutes or more.

NOTE-2: As part of this fix all temporary files will be removed. If you have any open web pages that have not been bookmarked please make sure you bookmark them now as all open applications will be automatically closed. Also, make sure you know the passwords for all websites as cookies will also be removed. The use of an external password manager is highly recommended instead of using your browser to store passwords.

The following directories are emptied:

  • Windows Temp
  • Users Temp folders
  • Edge, IE, FF, Chrome and Opera caches, HTML5 storages, Cookies and History
  • Recently opened files cache
  • Flash Player cache
  • Java cache
  • Steam HTML cache
  • Explorer thumbnail and icon cache
  • BITS transfer queue (qmgr*.dat files)
  • Recycle Bin

Important: items are permanently deleted. They are not moved to quarantine. If you have any questions or concerns please ask before running this fix.

The system will be rebooted after the fix has run.




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  • Root Admin

Thanks, the logs look pretty good. How is the computer running now?

Please follow the directions from the following topic to do a clean removal and reinstall of Malwarebytes

Uninstall and reinstall Malwarebytes using the Malwarebytes Support Tool


Then restart the computer after installing Malwarebytes and run the following program to check for program updates.

Patch My PC Home Updater


Once that's all done if  you still want to use ESET antivirus and there are no obvious issues go ahead and reinstall ESET antivirus

Let me know how it goes




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one thing i noticed in the new log files is a the messages related to nahimic (avolute) which may have been suppressed beforehand. I will of course take the issue up with nahimic after this, but it is interesting that the issue I have been having wasn't generating the driver signature errors before. is it even possible that those pathless tasks were suppressing the driver errors?


is it alright to clear out the dumps now? for me they are taking up considerable space which is at a premium.

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just ran into another issue, this time from windows code integrity. don't know if it is normal or not, but it sounds like something abnormal.


Code Integrity determined that a process (\Device\HarddiskVolume5\Program Files (x86)\Microsoft\Edge\Application\msedge.exe) attempted to load \Device\HarddiskVolume5\Program Files\Malwarebytes\Anti-Malware\mbae64.dll that did not meet the Microsoft signing level requirements.

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