Stands for Layered Service Provider. A Layered Service Provider is a file (.dll) using the Winsock API to insert itself into the TCP/IP stack. There it can intercept, filter, and even modify all the traffic between the internet and a system’s applications. More detailed information can be found in the blogpost Changes in the LSP stack. An example of an LSP hijacker can be found in the blogpost Fake Adblocker Bylekh is an LSP Hijacker.