Brute force and dictionary attacks in Cybersecurity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a brute force attack?

A brute force attack is a method where an attacker tries every possible combination of passwords or keys until the correct one is found. It is like trying every key on a keyring to open a locked door.

beginner

How does a dictionary attack differ from a brute force attack?

A dictionary attack uses a list of common words or passwords (called a dictionary) to guess the password, instead of trying every possible combination. It is faster but only works if the password is simple or common.

intermediate

Why are brute force attacks slow compared to dictionary attacks?

Brute force attacks try every possible combination, which can take a very long time, especially for long passwords. Dictionary attacks only try common or likely passwords, so they are faster but less thorough.

beginner

What is one common way to protect against brute force and dictionary attacks?

Using strong, long passwords with a mix of letters, numbers, and symbols makes it harder for attackers to guess. Also, limiting login attempts and using two-factor authentication helps protect accounts.

intermediate

What role do password hashing and salting play in defending against these attacks?

Password hashing converts passwords into a fixed code that is hard to reverse. Salting adds random data to passwords before hashing to make attacks like dictionary attacks much harder because attackers can't use pre-made lists.

What does a brute force attack try to do?

A Try every possible password combination

B Use a list of common passwords

C Steal passwords from a database

D Guess passwords based on user information

A brute force attack tries every possible password combination until it finds the correct one.

Which attack uses a pre-made list of common passwords?

A Dictionary attack

B Brute force attack

C Phishing attack

D Man-in-the-middle attack

A dictionary attack uses a list of common or likely passwords to guess the correct one.

Why is using a long and complex password important?

A It makes passwords easier to remember

B It allows attackers to guess faster

C It slows down brute force and dictionary attacks

D It prevents phishing attacks

Long and complex passwords increase the number of possible combinations, making attacks slower and harder.

What is salting in password security?

A Limiting login attempts

B Storing passwords in plain text

C Using common words as passwords

D Adding random data to passwords before hashing

Salting adds random data to passwords before hashing to make attacks like dictionary attacks more difficult.

Which method helps protect accounts from brute force attacks?

A Allow unlimited login attempts

B Use two-factor authentication

C Use simple passwords

D Share passwords with friends

Two-factor authentication adds an extra step to verify identity, making it harder for attackers to access accounts.

Explain in your own words how brute force and dictionary attacks work and how they differ.

Think about trying keys on a door versus trying only the keys you think might fit.

Describe at least two ways to protect your accounts from brute force and dictionary attacks.

Consider what makes guessing passwords harder and what stops repeated tries.

Practice

1. What is the main difference between a brute force attack and a dictionary attack?

easy

A. Brute force uses common passwords; dictionary tries all possible combinations.

B. Brute force tries all possible passwords; dictionary uses a list of common passwords.

C. Brute force attacks only numeric passwords; dictionary attacks only words.

D. Brute force attacks are faster than dictionary attacks.

Solution

1. Step 1: Understand brute force attack method

   Brute force attacks try every possible password combination without skipping any.

2. Step 2: Understand dictionary attack method

   Dictionary attacks try passwords from a predefined list of common or likely passwords.

3. Final Answer:

   Brute force tries all possible passwords; dictionary uses a list of common passwords. -> Option B

4. Quick Check:

   Brute force = all combos, Dictionary = common list [OK]

Hint: Brute force = all combos; dictionary = common words list [OK]

Common Mistakes:

• Confusing which attack uses all combinations
• Thinking dictionary attacks try all passwords
• Assuming brute force only tries common passwords

2. Which of the following is the correct description of a dictionary attack?

easy

A. Guessing passwords based on user personal information.

B. Trying every possible password combination systematically.

C. Using a list of common passwords to guess the correct one.

D. Intercepting passwords during transmission.

Solution

1. Step 1: Identify dictionary attack method

   Dictionary attacks use a list of common or likely passwords to guess the correct one.

2. Step 2: Eliminate other options

   Trying every possible password combination systematically. describes brute force, C is social engineering, D is interception, not dictionary attack.

3. Final Answer:

   Using a list of common passwords to guess the correct one. -> Option C

4. Quick Check:

   Dictionary attack = common password list [OK]

Hint: Dictionary attack uses common password lists, not all combos [OK]

Common Mistakes:

• Mixing dictionary attack with brute force
• Confusing social engineering with dictionary attack
• Thinking dictionary attacks intercept passwords

3. Consider this scenario: An attacker uses a program that tries passwords from a list of 1000 common passwords. Which type of attack is this?

medium

A. Dictionary attack

B. Phishing attack

C. Brute force attack

D. Man-in-the-middle attack

Solution

1. Step 1: Analyze the attack method

   The attacker tries passwords from a list of common passwords, not all possible combinations.

2. Step 2: Match attack type

   Trying passwords from a list matches the definition of a dictionary attack.

3. Final Answer:

   Dictionary attack -> Option A

4. Quick Check:

   Common password list = Dictionary attack [OK]

Hint: List of common passwords means dictionary attack [OK]

Common Mistakes:

• Calling it brute force because it tries many passwords
• Confusing phishing with password guessing
• Mixing man-in-the-middle with guessing attacks

4. A security analyst notices a login system is vulnerable because it allows unlimited password attempts without delay. What is the main risk here?

medium

A. It encrypts passwords too strongly.

B. It prevents dictionary attacks from working.

C. It blocks all password guessing attempts.

D. It allows brute force attacks to try many passwords quickly.

Solution

1. Step 1: Understand unlimited attempts impact

   Allowing unlimited attempts lets attackers try many passwords fast without being blocked.

2. Step 2: Identify risk type

   This makes brute force attacks easier because they rely on trying many combinations quickly.

3. Final Answer:

   It allows brute force attacks to try many passwords quickly. -> Option D

4. Quick Check:

   Unlimited attempts = easier brute force [OK]

Hint: Unlimited tries let brute force run fast [OK]

Common Mistakes:

• Thinking it prevents dictionary attacks
• Assuming it blocks guessing attempts
• Confusing encryption strength with login attempts

5. Which of the following is the best way to protect against both brute force and dictionary attacks?

hard

A. Use strong, unique passwords and enable account lockout after failed attempts.

B. Use only numeric passwords to make guessing easier.

C. Disable password requirements to speed up login.

D. Share passwords with trusted friends.

Solution

1. Step 1: Identify effective password practices

   Strong, unique passwords are hard to guess by brute force or dictionary attacks.

2. Step 2: Understand account lockout benefits

   Locking accounts after failed attempts stops attackers from trying many passwords quickly.

3. Step 3: Evaluate other options

   Options A, B, and D weaken security and increase risk.

4. Final Answer:

   Use strong, unique passwords and enable account lockout after failed attempts. -> Option A

5. Quick Check:

   Strong passwords + lockout = best defense [OK]

Hint: Strong passwords + lockout stops guessing attacks [OK]

Common Mistakes:

• Thinking simple numeric passwords are safer
• Disabling password rules to speed login
• Sharing passwords reduces security