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EC-Council

312-50V13 · Question #615

An ethical hacker is performing a network scan to evaluate the security of a company's IT infrastructure. During the scan, he discovers an active host with multiple open ports running various…

The correct answer is B. Conduct a vulnerability scan on the open port to identify any potential weaknesses. After successfully establishing an open TCP connection during a network scan, the ethical hacker's next logical step is to conduct a vulnerability scan on that open port to identify potential weaknesses.

Submitted by certguy· Mar 6, 2026Vulnerability Analysis

Question

An ethical hacker is performing a network scan to evaluate the security of a company's IT infrastructure. During the scan, he discovers an active host with multiple open ports running various services. The hacker uses TCP communication flags to establish a connection with the host and starts communicating with it. He sends a SYN packet to a port on the host and receives a SYN/ACK packet back. He then sends an ACK packet for the received SYN/ACK packet, which triggers an open connection. Which of the following actions should the ethical hacker perform next?

Options

  • ASend a PSH packet to inform the receiving application about the buffered data.
  • BConduct a vulnerability scan on the open port to identify any potential weaknesses.
  • CScan another port on the same host using the SYN, ACK, and RST flags.
  • DSend a FIN or RST packet to close the connection.

How the community answered

(26 responses)
  • A
    15% (4)
  • B
    73% (19)
  • C
    8% (2)
  • D
    4% (1)

Why each option

After successfully establishing an open TCP connection during a network scan, the ethical hacker's next logical step is to conduct a vulnerability scan on that open port to identify potential weaknesses.

ASend a PSH packet to inform the receiving application about the buffered data.

Sending a PSH packet is a part of TCP data transfer, not a primary step for reconnaissance or vulnerability assessment immediately after establishing a connection in this context.

BConduct a vulnerability scan on the open port to identify any potential weaknesses.Correct

Establishing a successful three-way handshake (SYN, SYN/ACK, ACK) confirms that a port is open and a service is actively listening. With an open connection identified, the ethical hacker should then conduct a vulnerability scan specifically targeting that service and port to discover known vulnerabilities, misconfigurations, or exploitable flaws that could lead to unauthorized access or further compromise.

CScan another port on the same host using the SYN, ACK, and RST flags.

Scanning another port using different flags is a good next step for overall network discovery but is not the most effective immediate action for assessing the security of the *already identified* open port and service.

DSend a FIN or RST packet to close the connection.

Sending a FIN or RST packet would close the connection, which is appropriate after completing an interaction but not the next action when the goal is to assess vulnerabilities of an *open* port.

Concept tested: Post-port scan vulnerability assessment

Topics

#TCP handshake#port scanning#vulnerability scan#network assessment

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