What type of scan should a penetration tester run to identify the most open services when lacking full access to generate raw packets?

A TCP connect scan is a technique used by penetration testers to determine which TCP ports are open on a target system. This method does not require raw packet generation and instead utilizes the operating system's functions to establish a complete TCP connection. When a penetration tester executes a TCP connect scan, they send connection requests to target ports, and based on the responses received (either a SYN-ACK for open ports or RST for closed ports), the tester can identify which services are accessible.

This method is particularly useful when the tester has limited capabilities, such as not being able to generate raw packets. It provides a direct and straightforward method of identifying open ports and services running on a host, helping to assess the security posture of the target system efficiently. Since it relies on standard connection routines within the operating system, it is considered reliable for this purpose. While there are other scanning techniques that can provide insight into open services, the TCP connect scan is most appropriate given the constraints of not having full access.