Proxy detection systems and methods

A proxy detection method includes: in response to receiving, from a client device, a first request to establish a transport-layer connection between the client device and the server, transmitting a first message to the client device according to a first handshake sequence, for establishing the transport-layer connection; determining a first time period associated with completion of the first handshake sequence; in response to receiving, from the client device over the transport-layer connection, a second request to establish a secure link between a client endpoint and the server, transmitting a second message to the client endpoint according to a second predefined handshake sequence, for establishing the secure link; determining a second time period associated with completion of the second handshake sequence; and generating, based on the first time period and the second time period, a score indicating a likelihood that the client device is a proxy for the client endpoint.