Information
This policy setting configures whether the device checks (in real time) with the Microsoft Active Protection Service (MAPS) before allowing certain content to be run or accessed.
The block at first sight feature works when Microsoft Defender Antivirus encounters a suspicious but undetected file. It then queries the Microsoft cloud protection backend and applies heuristics, machine learning, and automated analysis of the file to determine whether the files are malicious.
The recommended state for this setting is: Enabled.
Warning: This setting requires at least Microsoft Defender for Endpoint Plan 1 (Foundational enterprise endpoint protection) to function. If Plan 1 is not in use, an exception to this recommendation is required.
Enabling the Block at First Sight feature enhances threat protection by using next-generation protection to detect new malware and block it within seconds.
Solution
To establish the recommended configuration via GP, set the following UI path to Enabled :
Computer Configuration\Policies\Administrative Templates\Windows Components\Microsoft Defender Antivirus\MAPS\Configure the 'Block at First Sight' feature
Note: This Group Policy path is provided by the Group Policy template WindowsDefender.admx/adml that is included with the Microsoft Windows 8.1 & Server 2012 R2 Administrative Templates (or newer).
Impact:
The block at first sight can block nonportable executable files (such as JS, VBS, or macros) and executable files, running the latest Defender antimalware platform on Windows or Windows Server.
Note: The block at first sight feature requires the following Group Policy settings to be configured to function.
- Join Microsoft MAPS must be enabled.
- Send file samples when further analysis is required should be set to 1 (Send safe samples) or 3 (Send all samples)
- Scan all downloaded files and attachments must be enabled.
- Turn off real-time protection must NOT be enabled.