A new tool called Defendnot, developed by es3n1n, allows users to disable Windows Defender by using an undocumented Windows Security Center (WSC) API to simulate the presence of another antivirus program. This tool is a successor to the no-defender tool, which was taken down due to legal issues. Defendnot does not use third-party antivirus code and aims for a clean implementation. It disables Microsoft Defender upon activation, leaving users vulnerable to malware as it does not provide real-time scanning. Defendnot is designed to run automatically at Windows startup. Microsoft classifies Defendnot as a Trojan, raising concerns about its potential misuse by malicious actors.