What is Waitfor.exe and how can it be used for persistence in penetration testing?

Waitfor.exe is a Windows command-line tool used to synchronize computers on a network by sending or waiting for signals. In penetration testing, it can be exploited as a backdoor: an attacker configures it to wait for a specific signal and then execute a command, such as launching a PowerShell script that downloads and runs payloads. For more details, refer to Use Waitfor.exe to maintain persistence. This technique enables a remote activation mechanism, though the backdoor is non-reusable after one trigger unless a persistent loop is implemented.