https://www.bleepingcomputer.com/news/microsoft/microsoft-defender-can-ironically-be-used-to-download-malware/

A recent update to Windows 10's Microsoft Defender antivirus solution ironically allows it to download malware and other files to a Windows computer.

Legitimate operating system files that can be abused for malicious purposes are known as living-off-the-land binaries or LOLBINs.