Com port (Serial Port) being blocked by ESET

[Sylvester 0]

Hi there,

Strange issue.  I am using a Serial-USB adapter and have found it is being blocked by ESET.  I've tried changing com port numbers, disabling then re-enabling, uninstalling then reinstalling drivers (and have the latest drivers from FTDI).  If I 'Pause Firewall (Allow all traffic)' then I can receive info from the com port without issue.  I have an old laptop that is set up (theoretically identically) to the desktop I have issues with and it allows com port access without a problem.  I don't have 'device control' turned on on either machine and both have the latest ESET versions.

I should also note that the com port does exist in Device Manager and have tried to access it via Putty, Tera Term and even wrote a python script (all say 'Access Denied').  It is definitely an ESET (or somehow Defender) issue, not hardware.

Any ideas?

Cheers

 

Edited October 30, 2021 by Sylvester
Added details

[Sylvester 0]

Just did a bit more investigation and it seems to be a HIPS issue.  Turn off HIPS, and it all works.

[Sylvester 0]

OK, slightly more info.  I told HIPS to log things and get this when I try to connect to  the port:

Time;Application;Operation;Target;Action;Rule;Additional information
30/10/2021 3:12:01 pm;C:\Program Files\Logitech\Gaming Software\LWEMon.exe;Get access to another application;C:\Program Files\ESET\ESET Security\egui.exe;Blocked;Self-Defense: Protect ekrn and egui processes;Terminate/suspend another application,Modify state of another application,Get access to another application

 

[Sylvester 0]

Actually, ignore that HIPS warning, its clearly for something else.

[Marcos 5,443]

Is re-enabling HIPS, temporarily disabling only self-defense and rebooting the machine enough to make the problem go away?