Port scanning with Nmap in Cybersecurity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to scan all ports on a target IP using Nmap.

Cybersecurity

nmap -p [1] 192.168.1.1

Drag options to blanks, or click blank then click option'

A80

B443

C22

D1-65535

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single port number instead of a range.

Omitting the port option entirely.

The option -p 1-65535 tells Nmap to scan all ports from 1 to 65535 on the target IP.

2fill in blank

medium

Complete the command to perform a TCP SYN scan on a target IP.

Cybersecurity

nmap [1] 192.168.1.1

Drag options to blanks, or click blank then click option'

A-sS

B-sT

C-sV

D-sU

Attempts:

3 left

💡 Hint

Common Mistakes

Using -sU which is for UDP scans.

Using -sT which is a full TCP connect scan.

The -sS option performs a TCP SYN scan, which is a fast and stealthy scan type.

3fill in blank

hard

Fix the error in the command to scan ports 20 to 25 on a target IP.

Cybersecurity

nmap -p [1] 192.168.1.1

Drag options to blanks, or click blank then click option'

A20,25

B20-25

C20:25

D20_25

Attempts:

3 left

💡 Hint

Common Mistakes

Using a colon or underscore instead of a hyphen.

Using commas which specify separate ports, not a range.

The correct syntax for specifying a port range in Nmap is 20-25 using a hyphen.

4fill in blank

hard

Fill both blanks to scan a target IP with service version detection and OS detection.

Cybersecurity

nmap [1] [2] 192.168.1.1

Drag options to blanks, or click blank then click option'

A-sV

B-O

C-sS

D-p

Attempts:

3 left

💡 Hint

Common Mistakes

Using port scan options instead of detection options.

Mixing up the order of options.

-sV enables service version detection, and -O enables OS detection in Nmap scans.

5fill in blank

hard

Fill all three blanks to create a command that scans ports 80 and 443, performs a TCP connect scan, and outputs results in normal format.

Cybersecurity

nmap [1] -p [2] [3] 192.168.1.1

Drag options to blanks, or click blank then click option'

A-sT

B80,443

C-oN -

D-sS

Attempts:

3 left

💡 Hint

Common Mistakes

Using -sS instead of -sT for TCP connect scan.

Listing ports with a hyphen instead of commas.

Omitting the output format option.

-sT performs a TCP connect scan, -p 80,443 scans ports 80 and 443, and -oN outputs results in normal format.

Practice

1. What is the primary purpose of using nmap in cybersecurity?

easy

A. To find open ports on a network device

B. To encrypt network traffic

C. To create firewalls

D. To monitor user activity

Solution

1. Step 1: Understand what port scanning means

   Port scanning is the process of checking which ports on a device are open and listening for connections.

2. Step 2: Identify Nmap's role

   Nmap is a tool designed to perform port scanning to find open ports and services on devices.

3. Final Answer:

   To find open ports on a network device -> Option A

4. Quick Check:

   Port scanning = Finding open ports [OK]

Hint: Nmap scans ports to find open network services [OK]

Common Mistakes:

• Confusing port scanning with encryption
• Thinking Nmap creates firewalls
• Assuming Nmap monitors user activity

2. Which of the following is the correct basic syntax to scan a single IP address using Nmap?

easy

A. nmap -open 192.168.1.1

B. nmap scan 192.168.1.1

C. nmap --check 192.168.1.1

D. nmap -sS 192.168.1.1

Solution

1. Step 1: Recall Nmap command structure

   Nmap commands start with 'nmap' followed by options and then the target IP.

2. Step 2: Identify correct option for scanning

   The '-sS' option is a common scan type (TCP SYN scan) and is valid syntax.

3. Final Answer:

   nmap -sS 192.168.1.1 -> Option D

4. Quick Check:

   Correct Nmap scan syntax = nmap -sS 192.168.1.1 [OK]

Hint: Use 'nmap -sS <IP>' for a basic TCP SYN scan [OK]

Common Mistakes:

• Using 'scan' as a command option
• Using invalid options like '-open' or '--check'
• Omitting the scan type option

3. What will be the result of running nmap -p 22,80 192.168.0.10?

medium

A. Scan ports 22 and 80 on 192.168.0.10

B. Scan all ports on 192.168.0.10

C. Scan ports 22 to 80 on 192.168.0.10

D. Scan only port 80 on 192.168.0.10

Solution

1. Step 1: Understand the '-p' option in Nmap

   The '-p' option specifies which ports to scan. Comma-separated values mean specific ports.

2. Step 2: Analyze the ports listed

   Ports 22 and 80 are explicitly listed, so only these two ports will be scanned.

3. Final Answer:

   Scan ports 22 and 80 on 192.168.0.10 -> Option A

4. Quick Check:

   '-p 22,80' means scan ports 22 and 80 [OK]

Hint: Comma lists in '-p' scan only those ports [OK]

Common Mistakes:

• Assuming '-p 22,80' scans all ports
• Thinking it scans a range from 22 to 80
• Ignoring the port list format

4. Identify the error in this Nmap command: nmap -p 80-22 192.168.1.5

medium

A. IP address format is incorrect

B. Port range is reversed; should be 22-80

C. Missing scan type option

D. No error; command is correct

Solution

1. Step 1: Check port range syntax

   Port ranges must be in ascending order, e.g., 22-80, not 80-22.

2. Step 2: Verify other parts of the command

   The IP address format is correct, and scan type is optional; default scan works.

3. Final Answer:

   Port range is reversed; should be 22-80 -> Option B

4. Quick Check:

   Port ranges must ascend, not descend [OK]

Hint: Port ranges must go from smaller to larger number [OK]

Common Mistakes:

• Using descending port ranges
• Thinking IP format is wrong
• Believing scan type is always required

5. You want to scan a network range from 192.168.1.1 to 192.168.1.254 for open HTTP ports (port 80) only. Which Nmap command should you use?

hard

A. nmap -p 80 192.168.1.0-254

B. nmap -p 80 192.168.1.1/24

C. nmap -p 80 192.168.1.1-192.168.1.254

D. nmap -p 80 192.168.1.0/24

Solution

1. Step 1: Understand how to specify IP ranges in Nmap

   Nmap accepts explicit ranges like '192.168.1.1-192.168.1.254' to scan all addresses in that range.

2. Step 2: Check port and target correctness

   Port 80 is specified correctly with '-p 80'. The range '192.168.1.1-192.168.1.254' covers all hosts from .1 to .254.

3. Step 3: Evaluate other options

   nmap -p 80 192.168.1.0-254 scans from 192.168.1.0 to 192.168.1.254, including the unwanted network address .0. nmap -p 80 192.168.1.1/24 uses CIDR /24 which scans the entire subnet (.0 to .255). nmap -p 80 192.168.1.0/24 scans the entire subnet including .0 and .255.

4. Final Answer:

   nmap -p 80 192.168.1.1-192.168.1.254 -> Option C

5. Quick Check:

   Explicit IP range with '-p 80' = nmap -p 80 192.168.1.1-192.168.1.254 [OK]

Hint: Use full IP range for precise scanning [OK]

Common Mistakes:

• Using shorthand range 192.168.1.0-254 (includes .0)
• Confusing CIDR notation with explicit ranges
• Including network address (.0) in scan