Teams.exe

Electron runtime binary which runs the Teams application

Paths

• C:\Users\<username>\AppData\Local\Microsoft\Teams\current\Teams.exe

Commands

Execute

Generate JavaScript payload and package.json, and save to "%LOCALAPPDATA%\\Microsoft\\Teams\\current\\app\\" before executing.

Use case: Execute JavaScript code

Privileges: User

teams.exe

Execute

Generate JavaScript payload and package.json, archive in ASAR file and save to "%LOCALAPPDATA%\\Microsoft\\Teams\\current\\app.asar" before executing.

Use case: Execute JavaScript code

Privileges: User

teams.exe

Execute

Teams spawns cmd.exe as a child process of teams.exe and executes the ping command

Use case: Executes a process under a trusted Microsoft signed binary

Privileges: User

teams.exe --disable-gpu-sandbox --gpu-launcher="{CMD} &&"

Detection

• IOC: %LOCALAPPDATA%\Microsoft\Teams\current\app directory created
• IOC: %LOCALAPPDATA%\Microsoft\Teams\current\app.asar file created/modified by non-Teams installer/updater
• Sigma: https://github.com/SigmaHQ/sigma/blob/43277f26fc1c81fc98fc79147b711189e901b757/rules/windows/process_creation/proc_creation_win_susp_electron_exeuction_proxy.yml

Resources

• https://l--k.uk/2022/01/16/microsoft-teams-and-other-electron-apps-as-lolbins/