BlockInput

As per Microsoft's documentation, BlockInput function "prevents keyboard and mouse input events from reaching applications," effectively restricting user interaction with the system.

Malware occasionally employs this tactic to hinder analysis by debuggers or other analysis tools throughout the process' runtime. To deactivate the block, the program must make a live call to BlockInput with the parameter 0. Windows automatically lifts the block when the process ends or the user initiates Ctrl+Alt+Del.


Technique Identifier

U1011

Technique Tags

blockinput keyboard

Evasion Categories

Contributor

Additional Resources

External Links
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Created

March 22, 2024

Last Revised

March 24, 2026