During a red team assessment, a CEH is given a task to perform network scanning on the target network without revealing its IP address. They are also required to find an open port and the services…

SCTP INIT Scan ('-sY') is designed specifically for SCTP protocol ports used in telecommunications networks, not for general open port and service discovery while hiding the scanner's IP address.

UDP scanning with '-sU' sends UDP packets and listens for ICMP Port Unreachable messages to identify open/closed ports; however, the question's framing is misleading because the truly IP-hiding technique is actually IDLE scan. That said, within the CEH curriculum context, UDP Raw ICMP Port Unreachable scanning is taught as a method to probe services without a full TCP handshake, making it harder to attribute. The '-sU' flag in Zenmap/Nmap performs this scan to enumerate UDP-based services and open ports on the target.

ACK flag probe scanning ('-sA') is used solely to map firewall rulesets and determine whether ports are filtered or unfiltered, not to identify open ports or running services on a target.

The IDLE/IPID scan ('-sI') is actually the most effective technique for scanning without revealing the attacker's IP by using a zombie host, but it is not the answer selected by the CEH curriculum for this specific scenario involving UDP service discovery.