Common network protocols and vulnerabilities in Cybersecurity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the HTTP protocol?

HTTP (HyperText Transfer Protocol) is used to transfer web pages from servers to browsers, allowing users to view websites.

beginner

What does the TCP protocol do in networking?

TCP (Transmission Control Protocol) ensures reliable, ordered, and error-checked delivery of data between devices on a network.

intermediate

What is a common vulnerability of the FTP protocol?

FTP (File Transfer Protocol) often transmits data, including passwords, in plain text, making it vulnerable to interception and eavesdropping.

beginner

What is a Denial of Service (DoS) attack?

A DoS attack floods a network or service with excessive traffic to make it unavailable to legitimate users.

intermediate

Why is using outdated protocols like Telnet considered risky?

Telnet sends data, including passwords, without encryption, making it easy for attackers to intercept sensitive information.

Which protocol is commonly used to securely browse websites?

A SMTP

B FTP

C Telnet

D HTTPS

HTTPS encrypts data between the browser and server, making web browsing secure.

What vulnerability does FTP commonly have?

A Data sent in plain text

B Automatic encryption

C Limited file size

D Slow transfer speed

FTP sends data, including passwords, without encryption, exposing it to interception.

Which attack aims to make a network service unavailable by overwhelming it?

A Phishing

B Denial of Service (DoS)

C Man-in-the-middle

D SQL Injection

DoS attacks flood a service with traffic to disrupt normal access.

Which protocol is NOT secure because it sends data unencrypted?

A SSH

B HTTPS

C Telnet

D SFTP

Telnet transmits data in plain text, making it insecure.

What does TCP ensure in data transmission?

A Data is sent without errors and in order

B Data is compressed

C Data is encrypted

D Data is broadcast to all devices

TCP provides reliable, ordered, and error-checked delivery of data.

Explain the difference between HTTP and HTTPS and why HTTPS is important.

Think about how websites keep your information safe.

Describe common vulnerabilities in network protocols and how attackers exploit them.

Consider what happens when data is not protected.

Practice

1. Which protocol is primarily used to securely browse websites by encrypting data between your browser and the server?

easy

A. HTTPS

B. FTP

C. HTTP

D. DNS

Solution

1. Step 1: Understand the purpose of HTTPS

   HTTPS stands for HyperText Transfer Protocol Secure and encrypts data to protect privacy.

2. Step 2: Compare with other protocols

   HTTP is not secure, FTP is for file transfer, and DNS resolves domain names, none encrypt data like HTTPS.

3. Final Answer:

   HTTPS -> Option A

4. Quick Check:

   Secure web browsing = HTTPS [OK]

Hint: Secure web browsing uses HTTPS, not HTTP or FTP [OK]

Common Mistakes:

• Confusing HTTP with HTTPS
• Thinking FTP encrypts web data
• Assuming DNS secures browsing

2. Which of the following is the correct port number for the FTP protocol by default?

easy

A. 80

B. 21

C. 443

D. 53

Solution

1. Step 1: Recall default FTP port

   FTP (File Transfer Protocol) uses port 21 by default for control commands.

2. Step 2: Identify other ports

   Port 80 is for HTTP, 443 for HTTPS, and 53 for DNS, so they are incorrect for FTP.

3. Final Answer:

   21 -> Option B

4. Quick Check:

   FTP default port = 21 [OK]

Hint: FTP control commands use port 21 by default [OK]

Common Mistakes:

• Choosing port 80 (HTTP) for FTP
• Confusing HTTPS port 443 with FTP
• Selecting DNS port 53

3. Consider this simplified code snippet simulating a DNS query response check:

response = {'status': 'NOERROR', 'data': '1.2.3.4'}
if response['status'] == 'NOERROR':
    print('Valid IP:', response['data'])
else:
    print('Error in DNS response')

What will be printed?

medium

A. Valid IP: 1.2.3.4

B. KeyError

C. Valid IP: NOERROR

D. Error in DNS response

Solution

1. Step 1: Check the condition on response status

   The code checks if response['status'] equals 'NOERROR', which it does.

2. Step 2: Determine the printed output

   Since condition is true, it prints 'Valid IP:' followed by response['data'], which is '1.2.3.4'.

3. Final Answer:

   Valid IP: 1.2.3.4 -> Option A

4. Quick Check:

   response['status'] == 'NOERROR' prints IP [OK]

Hint: Check condition first; if true, print IP from data key [OK]

Common Mistakes:

• Confusing status with data value
• Expecting error when none occurs
• Assuming KeyError without missing keys

4. A network administrator notices that FTP traffic is being intercepted and credentials stolen. Which vulnerability is most likely being exploited?

medium

A. SQL Injection

B. DNS Spoofing

C. Man-in-the-Middle Attack

D. Cross-Site Scripting

Solution

1. Step 1: Identify the nature of the attack

   Intercepting FTP traffic and stealing credentials indicates someone is spying on communication.

2. Step 2: Match with known vulnerabilities

   Man-in-the-Middle (MitM) attacks intercept and alter communication between two parties, fitting this scenario.

3. Final Answer:

   Man-in-the-Middle Attack -> Option C

4. Quick Check:

   Intercepted FTP = Man-in-the-Middle [OK]

Hint: Intercepted communication usually means Man-in-the-Middle attack [OK]

Common Mistakes:

• Confusing with DNS Spoofing
• Thinking SQL Injection affects FTP
• Mixing with Cross-Site Scripting

5. You want to secure a company's email communication. Which protocol should you use to encrypt emails during transmission to prevent eavesdropping?

hard

A. FTP

B. Telnet

C. HTTP

D. SMTP with STARTTLS

Solution

1. Step 1: Identify email transmission protocols

   SMTP is the standard protocol for sending emails, but by default it is unencrypted.

2. Step 2: Choose encryption method for SMTP

   STARTTLS upgrades SMTP to use encryption, protecting emails from eavesdropping during transmission.

3. Step 3: Exclude other protocols

   FTP is for file transfer, HTTP is for web browsing, and Telnet is insecure remote access; none encrypt email.

4. Final Answer:

   SMTP with STARTTLS -> Option D

5. Quick Check:

   Email encryption during send = SMTP + STARTTLS [OK]

Hint: Use SMTP with STARTTLS to encrypt email sending [OK]

Common Mistakes:

• Choosing FTP or HTTP for email
• Ignoring encryption in SMTP
• Selecting Telnet which is insecure