Question 1

A computer that receives a SYN packet from a remote computer responds to the packet with a(n) ____ packet if its port is open.

Accepted Answer

When a computer receives a SYN packet from a remote computer, it responds with a SYN/ACK packet if its port is open. This is a three-way handshake process, in which the SYN packet is the first step, the SYN/ACK packet is the second step, and the ACK packet is the third and final step. The SYN/ACK packet indicates that the computer is willing to establish a connection with the remote computer.

Question 2

____ was developed to assist security testers in conducting tests on large networks and to consolidate many of the tools needed for large-scale endeavors.

Accepted Answer

Unicornscan was developed to assist security testers in conducting tests on large networks and to consolidate many of the tools needed for large-scale endeavors.

Question 3

The ____ relies on the OS of the attacked computer, so it's a little more risky to use than the SYN scan.

Accepted Answer

The connect scan is considered the most reliable and stealthy scan because it simulates a normal connection attempt, and if the connection is successful, it immediately terminates it. The NULL, XMAS, and ACK scans rely on specific flags to be set in the packet header, which can be filtered or blocked by firewalls or intrusion detection systems.

Question 4

____ is a protocol packet analyzer.

Accepted Answer

Tcpdump is a widely used command-line based packet analyzer for analyzing network traffic based on the TCP/IP protocols. It captures packets that traverse specific network interfaces and displays them in real-time or saves them to a file for later analysis. Nmap is a network exploration tool used to identify hosts and services on a network, Fping is a ping program used to check the reachability of hosts on a network, and Nessus is a vulnerability scanner used to identify vulnerabilities in hosts and networks.

Question 5

____, an open-source fork of Nessus, functions much like a database server, performing complex queries while the client interfaces with the server to simplify reporting and configuration.

Accepted Answer

OpenVAS is an open-source fork of Nessus and functions like a database server, allowing for complex queries while simplifying reporting and configuration for the client interface. Unicornscan is a network enumeration tool, NetScanTools is a suite of network utilities, and Nmap is a network exploration and security auditing tool, but none of them function like a database server in the same way that OpenVAS does.

Question 6

____ is a reasonably priced commercial port scanner with a GUI interface.

Accepted Answer

AW Security Port Scanner is a reasonably priced commercial port scanner with a GUI interface. Common Vulnerabilities and Exposures is not a port scanner, Ethereal is a packet analyzer, and Tcpdump is a command-line network monitoring tool.

Question 7

A closed port can be vulnerable to an attack.

Accepted Answer

The answer of A closed port can be vulnerable to...

Question 8

A disadvantage of Nmap is that it is very slow because it scans all the 65,000 ports of each computer in the IP address range.

Accepted Answer

Nmap has the ability to be customized to scan only specific ports or a range of ports, which can significantly reduce scan time. Additionally, the use of various scan techniques (such as SYN scans) can further increase efficiency. Therefore, Nmap is not necessarily slow by default.

Question 9

Unicornscan optimizes ____ scanning beyond the capabilities of any other port scanner.

Accepted Answer

Unicornscan is specially designed to optimize UDP scanning, making it faster and more efficient than other port scanners. While it can also scan TCP and ICMP, it excels at UDP scanning.

Question 10

The ____ tool was originally written for Phrack magazine in 1997 by Fyodor.

Accepted Answer

The tool originally written for Phrack magazine in 1997 by Fyodor is Nmap.

Question 11

Port scanning is a method of finding out which services a host computer offers.

Accepted Answer

Port scanning involves scanning a host's ports to identify which services or applications are running on that host. This information can be used for security testing or to identify potential vulnerabilities.

Question 12

When a TCP three-way handshake ends, both parties send a(n) ____ packet to end the connection.

Accepted Answer

When a TCP three-way handshake ends, both parties send a FIN packet to end the connection. The FIN packet indicates that the sender has no more data to transmit. The receiver acknowledges the FIN packet with an ACK packet, indicating that it has received the FIN packet and confirming that it is ready to close the connection.

Question 13

Closed ports respond to a(n) ____ with an RST packet.

Accepted Answer

The answer of Closed ports respond to a(n) ____ with...

Question 14

You can search for known vulnerabilities in a host computer by using the Common Vulnerabilities and Exposures Web site.

Accepted Answer

The Common Vulnerabilities and Exposures (CVE) Web site is a centralized repository of publicly known cybersecurity vulnerabilities and exposures. It can be used to search for known vulnerabilities in a host computer.

Question 15

____ is currently the standard port-scanning tool for security professionals.

Accepted Answer

Nmap (Network Mapper) is currently the most widely used port-scanning tool by security professionals. It is known for its versatility, flexibility, and accuracy in scanning networks and detecting open ports and vulnerabilities. Nmap offers various features such as OS detection, vulnerability scanning, scripting capabilities, and customizable output formats, making it an indispensable tool for network reconnaissance and security assessment.

Question 16

HTTP uses port ____ to connect to a Web service.

Accepted Answer

HTTP uses port 80 to connect to a Web service.

Question 17

The ____ option of Nmap is used to perform a TCP SYN stealth port scan.

Accepted Answer

The -sS option of Nmap is used to perform a TCP SYN stealth port scan. This option sends a SYN packet to the target port and waits for a SYN-ACK packet to confirm the port is open. This method is stealthier than other scan types as it does not complete the TCP three-way handshake.

Question 18

With the ____ tool, you can ping multiple IP addresses simultaneously.

Accepted Answer

The Fping tool allows you to send ICMP echo requests to multiple IP addresses simultaneously and uses the response time to determine if the host is active or not. Nmap is a port scanner, Nessus is a vulnerability scanner, and Unicornscan is a network reconnaissance tool that combines port scanning, OS fingerprinting, and more.

Question 19

A closed port responds to a SYN scan with an RST packet, so if no packet is received, the best guess is that the port is open.

Accepted Answer

The statement is incorrect. A closed port responds to a SYN scan with an RST packet, while an open port responds with a SYN-ACK packet. If the scanner receives no response at all, it is more likely that the port is filtered, meaning that a firewall or other network device is blocking the traffic.

Question 20

In an ACK scan, if the attacked port returns an RST packet the attacked port is considered to be "____".

Accepted Answer

In an ACK scan, if an RST packet is returned, it indicates that the port is "unfiltered," meaning the packet was not blocked by a firewall, but the scan does not determine if the port is open or closed.

Quiz 5: Port Scanning