Description

An adversary uses full TCP connection attempts to determine if a port is open on the target system. The scanning process involves completing a 'three-way handshake' with a remote port, and reports the port as closed if the full handshake cannot be established. An advantage of TCP connect scanning is that it works against any TCP/IP stack.

Prerequisites

The adversary requires logical access to the target network. The TCP connect Scan requires the ability to connect to an available port and complete a 'three-way-handshake' This scanning technique does not require any special privileges in order to perform. This type of scan works against all TCP/IP stack implementations.

Mitigations

Employ a robust network defense posture that includes an IDS/IPS system.