Bug 170040 - False positive from winget validation AV TRELLIX ENS for 26.2.0.0.beta1 x86
Summary: False positive from winget validation AV TRELLIX ENS for 26.2.0.0.beta1 x86
Status: UNCONFIRMED
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Installation (show other bugs)
Version:
(earliest affected)
26.2.0.0 alpha0+ master
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard: QA:needsComment
Keywords:
Depends on:
Blocks:
 
Reported: 2025-12-19 04:12 UTC by gary.meltzer
Modified: 2026-01-11 03:11 UTC (History)
0 users

See Also:
Crash report or crash signature:


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Description gary.meltzer 2025-12-19 04:12:33 UTC
Description:
I've started creating winget manifests for the LibreOffice pre-releases. The validation stage is failing because of a, presumably!, false positive for inprocserv.dll in LibreOfficeDev_26.2.0.0.beta1_Win_x86.msi , shown as W32/Patcher, which I kind of understand. The AV causing this result is TRELLIXENS, and I've not been able to report it there. I'm hoping you have better contacts/skills than me.

For reference, the Pull Request is https://github.com/microsoft/winget-pkgs/pull/321771 and I've had some discussions already with the team there.

Steps to Reproduce:
1.See https://github.com/microsoft/winget-pkgs/pull/321771
2.Trigger a validation run


Actual Results:
One or more ESRP Scan Blocking detections found:
Installer: LibreOfficeDev_26.2.0.0.beta1_Win_x86.msi
InstallerSha256: fa171e7038eb863ca25f7039bcd411d60fb5f933117c49bdf6ccd84a2b97cd7c

FileName	SHA256HexFileHash	Detection Engine	Detection Description
inprocserv.dll	4f50e5b881c2abfc0afc129899a5af3223b6af6cbcfc8080d501dc227632c4e2	TRELLIXENS	the W32/Patcher virus !!!

Expected Results:
A clean run.


Reproducible: Always


User Profile Reset: No

Additional Info:
This hasn't been seen on production LibreOffice winget packages, nor 26.2.0.0.alpha1 nor other architectures. So far anyway.

By the way, any help on winget is appreciated!
Comment 1 gary.meltzer 2025-12-27 00:29:57 UTC
Reported to Trellix.


FALSE POSITIVE REPORT

Detection Details:

Product: Trellix ENS (Endpoint Security)
Threat Name: W32/Patcher virus
Detected File: inprocserv.dll
File SHA-256: 4f50e5b881c2abfc0afc129899a5af3223b6af6cbcfc8080d501dc227632c4e2

Source Information:

Origin: LibreOffice Development Build
Source URL: https://downloadarchive.documentfoundation.org/libreoffice/old/26.2.0.0.beta1/win/x86/LibreOfficeDev_26.2.0.0.beta1_Win_x86.msi
MSI SHA-256: fa171e7038eb863ca25f7039bcd411d60fb5f933117c49bdf6ccd84a2b97cd7c

Evidence This Is a False Positive:

1. Microsoft Defender does not flag this file as malicious
2. LibreOffice's official security page (https://www.libreoffice.org/about-us/security/) explicitly states: "If your virus checker is flagging a LibreOffice download as containing a virus, this is almost certainly a false positive"
3. LibreOffice is a reputable open-source project maintained by The Document Foundation
4. LibreOffice releases undergo extensive testing and are used by millions globally

Impact:

Blocking winget packaging of LibreOffice preview beta1
Comment 2 gary.meltzer 2025-12-27 00:31:24 UTC
Ambiguous response from Trellix:


Trellix Labs                                                                           
Current Scan Engine Version:6810.10716                                                 
Current DAT Version:5000.0000                                                         
Thank you for your submission.                                                         

Analysis ID: 11196545

File Name            Findings                       Detection                    Type         Extra
--------------------|------------------------------|----------------------------|------------|-----
inprocserv.dll.sampl|current detection             |w32/patcher                 |Virus       |no   

current detection [inprocserv.dll.sample]                                                               

   The file submitted is malware that can be detected with current DAT files. It is       
recommended that you update your DAT and engine files and scan your computer again.   


                                                                                      
Regards,                                                                               
                                                                                      

                                                                                      
Trellix Labs