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Issue 851562 link

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Issue metadata

Status: Fixed
Owner:
Closed: Jun 2018
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug



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docs\gpu\debugging_gpu_related_code.md detected as malware by Windows Defender

Project Member Reported by brucedaw...@chromium.org, Jun 11 2018

Issue description

This markdown file is detected as Exploit:HTML/CVE-2018-1000006.A. If the Chromium repo is scanned by Windows Defender then the file will be quarantined. If the file is in a directory which is excluded from scanning then the problem will be avoided temporarily but if the file is copied elsewhere or if an attempt is made to backup the machine with Windows Backup then this will fail.

To be clear, a *markdown* file is being tagged as malware, and this will prevent some computers from being backed up.

The file was submitted to Microsoft as an example of incorrect detection. Their response was:

"Detection is intended. CVE-2018-1000006 is a remote code execution vulnerability affecting Electron apps that use custom protocol handlers. Best regards, Windows Defender Response"

https://www.microsoft.com/en-us/wdsi/submission/cae152af-9056-46c0-8546-f1e992a92f2f

The file in question is this one:

https://cs.chromium.org/chromium/src/docs/gpu/debugging_gpu_related_code.md?q=f:debugging_gpu&sq=package:chromium&g=0

Experimentation has shown that the markdown file can be minimized to this and still be detected as malicious:

--no-sandbox --gpu-launcher="x"

Yep, a 31-byte text file is detected as an exploit. It's not clear to me how this "payload" is triggered.

Twitter thread is here:
https://twitter.com/BruceDawson0xB/status/1005233795081990144

 
Owner: brucedaw...@chromium.org
Status: Started (was: Untriaged)
The best explanation I've seen is here:

https://hackernoon.com/exploiting-electron-rce-in-exodus-wallet-d9e6db13c374

That's motivated me to create a "fix" which removes use of --gpu-launcher through linguistic manipulation.
Project Member

Comment 2 by bugdroid1@chromium.org, Jun 12 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f17419f4169a63f890e756d74613c5dd8fb5b94d

commit f17419f4169a63f890e756d74613c5dd8fb5b94d
Author: Bruce Dawson <brucedawson@chromium.org>
Date: Tue Jun 12 01:47:03 2018

Modify markdown to satisfy Windows Defender

debugging_gpu_related_code.md explains how to use a Chrome command-line
switch which has been used for arbitrary code execution. Windows
Defender therefore treats it as malware. This means that some Windows
Chromium developers will get anti-virus warnings (with mandatory
quarantining of the file). If Chrome is in a directory that is
excluded from scanning then they will avoid warnings but will hit
problems if they try to use Windows backup.

This is all very silly since there is no way - short of manually
following the steps, modify to be malicious - to activate this payload.
Windows Defender even complains about the file created by this:

  > echo --no-sandbox --gpu-launcher="x" >foo.txt

But, sometimes it's not worth arguing.

This also fixes a typo.

R=kainino@chromium.org
BUG= 851562 

Change-Id: I85403a1cb1667f45784684179927119058608d40
Reviewed-on: https://chromium-review.googlesource.com/1096311
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566245}
[modify] https://crrev.com/f17419f4169a63f890e756d74613c5dd8fb5b94d/docs/gpu/debugging_gpu_related_code.md

Status: Fixed (was: Started)
I just got an official response saying that the detection has been fixed, and I can confirm that the file is no longer detected as a virus.

https://twitter.com/WDSecurity/status/1007042157255933952

The submission has also been updated so that it now says Not malware.

https://www.microsoft.com/en-us/wdsi/submission/cae152af-9056-46c0-8546-f1e992a92f2f

I'll revert the change.

Project Member

Comment 5 by bugdroid1@chromium.org, Jun 14 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a33b7c45d8bdb5af7caba7ed565be773b35a4db7

commit a33b7c45d8bdb5af7caba7ed565be773b35a4db7
Author: Bruce Dawson <brucedawson@chromium.org>
Date: Thu Jun 14 16:22:23 2018

Revert "Modify markdown to satisfy Windows Defender"

This reverts commit f17419f4169a63f890e756d74613c5dd8fb5b94d.

Reason for revert: Microsoft responded to twitter reports and fixed
their detection so this isn't needed anymore. I'm retaining the typo
fix though!

Original change's description:
> Modify markdown to satisfy Windows Defender
> 
> debugging_gpu_related_code.md explains how to use a Chrome command-line
> switch which has been used for arbitrary code execution. Windows
> Defender therefore treats it as malware. This means that some Windows
> Chromium developers will get anti-virus warnings (with mandatory
> quarantining of the file). If Chrome is in a directory that is
> excluded from scanning then they will avoid warnings but will hit
> problems if they try to use Windows backup.
> 
> This is all very silly since there is no way - short of manually
> following the steps, modify to be malicious - to activate this payload.
> Windows Defender even complains about the file created by this:
> 
>   > echo --no-sandbox --gpu-launcher="x" >foo.txt
> 
> But, sometimes it's not worth arguing.
> 
> This also fixes a typo.
> 
> R=​kainino@chromium.org
> BUG= 851562 
> 
> Change-Id: I85403a1cb1667f45784684179927119058608d40
> Reviewed-on: https://chromium-review.googlesource.com/1096311
> Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
> Reviewed-by: Kai Ninomiya <kainino@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#566245}

TBR=brucedawson@chromium.org,kainino@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  851562 
Change-Id: I60b09d8e6a698c1646f5c4bb0ecab16f999bfb9c
Reviewed-on: https://chromium-review.googlesource.com/1100255
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567294}
[modify] https://crrev.com/a33b7c45d8bdb5af7caba7ed565be773b35a4db7/docs/gpu/debugging_gpu_related_code.md

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