Remote activation of covert service channels is provided. A remote host can initiate and establish a connection with a target host without exposing a service channel or communications port to an unauthenticated host. Triggers can be received by and sent to a host and an associated operating system, under direction of a stealth listener. The stealth listener provides can control and direct an operating system to respond to incoming data packets, but can also open and close ports to enable access to services on a host. Using a variety of transport mechanisms, protocols, and triggers to covertly enable a connection to be established between a service and a remote client, the disclosed techniques also enable reduction of processing and storage resources by reducing the amount of host or client-installed software.