SilenTeams

Finally, a way to disable taskbar flashing

Preamble

So as many of us are painfully aware of, there is no way of disabling taskbar flashing for Microsoft Teams.

Furthermore, it completely ignores the HKEY_CURRENT_USER\Control panel\Desktop\ForegroundFlashCount registry key by just calling FlashWindowEx multiple times in a row. Why they do that is beyond me.

This is of course completely unacceptable and insanely harmful to the productivity of a workforce which - caused by a pandemic - is using Teams more than ever.

Even though that it's now December of 2020 with a Feedback Thread being open since April 2017, nothing about this situation changed.

Therefore, the nuclear option was chosen.

Description

This repository's release section contains a .dll file, which you can simply throw into your MS Teams installation folder to forcefully stop it from annoying you any further.

You are of course encouraged to build it yourself instead of just downloading a binary file. After all, this DLL could in theory inject anything into your Teams Process.

Installation

Download the SilenTeamsInstaller.ps1 and run it.

PowerShell one-liner to run the latest install script:

Set-ExecutionPolicy -ExecutionPolicy Unrestricted -Scope Process -Force; Invoke-WebRequest -UseBasicParsing https://raw.githubusercontent.com/Hypfer/SilenTeams/master/SilenTeamsInstaller.ps1 | Invoke-Expression

Manual Installation

1. Place the fake dbghelp.dll in %LOCALAPPDATA%\Microsoft\Teams\current and also copy C:\Windows\System32\dbghelp.dll to %LOCALAPPDATA%\Microsoft\Teams\current\dbghelp_orig.dll.

2. Start Teams

3. Enjoy not being disturbed by never-ending taskbar flashing.

Note that this will not survive a Teams updates. In that case, simply repeat step 1 and be happy again. :)

How it works

This project is a DLL which pretends to be another DLL which is used by MS Teams and proxys all calls to the original one.

This allows us to inject our own code into Teams which simply overwrites first byte of the FlashWindowEx function of the user32.dll in memory with a 0xC3 which is the x86 opcode for RETN or something like that.

So basically this no-ops FlashWindowEx without any additional functions, trampolines etc, because when building this, it was discovered that those broke for reasons that are beyond my understanding of computers.

Misc

Be advised that I usually use JavaScript to solve all my problems. This solution might be very bad, cause crashes and whatnot. Still, it solves a problem I had, and I'm happy to share it with you.

Feel free to open a PR to enhance it :)

Sources/Inspiration

Mutegram by mxs42
Windows Privilege Escalation - DLL Proxying by itm4n
NoFlashWindow by mrexodia

https://en.wikipedia.org/wiki/X86_instruction_listings