Prompt injection defense in Prompt Engineering / GenAI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to safely add user input to the prompt.

Prompt Engineering / GenAI

safe_prompt = base_prompt + ' User says: ' + [1]

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

Auser_input

Bsanitize(user_input)

Craw_input

Dinput()

Attempts:

3 left

💡 Hint

Common Mistakes

Using raw user input without cleaning.

Using input() which reads new input instead of the variable.

Using sanitize(user_input) helps remove harmful parts from the input before adding it to the prompt.

2fill in blank

medium

Complete the code to detect prompt injection keywords.

Prompt Engineering / GenAI

if '[1]' in user_input.lower():
    alert('Possible injection detected')

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

Aignore previous command

Bdelete all

Cignore previous

Dignore previous instructions

Attempts:

3 left

💡 Hint

Common Mistakes

Using incomplete or incorrect phrases that don't match injection attempts.

Checking for unrelated words.

The phrase 'ignore previous instructions' is a common injection attempt to override the prompt.

3fill in blank

hard

Fix the error in the function that blocks injection by replacing dangerous words.

Prompt Engineering / GenAI

def block_injection(text):
    blocked_text = text.replace([1], '[REDACTED]')
    return blocked_text

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

A'ignore previous instructions'

Bignore previous instructions

C'ignore previous'

D'delete all'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a variable name without quotes causes a NameError.

Using incomplete phrases that don't match the injection.

The replace method needs the first argument as a string literal, so it must be in quotes.

4fill in blank

hard

Fill both blanks to create a safe prompt by filtering and then formatting user input.

Prompt Engineering / GenAI

def create_safe_prompt(user_input):
    filtered = [1](user_input)
    prompt = f"System: Follow rules. User says: [2]"
    return prompt

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

Asanitize

Buser_input

Cfiltered

Dclean_input

Attempts:

3 left

💡 Hint

Common Mistakes

Using the original user_input directly in the prompt.

Mixing variable names incorrectly.

First sanitize the input, then use the filtered result in the prompt string.

5fill in blank

hard

Fill all three blanks to check for injection and respond safely.

Prompt Engineering / GenAI

def respond(user_input):
    if [1] in user_input.lower():
        return '[2]'
    safe_input = [3](user_input)
    return f"Processed: {safe_input}"

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

A'ignore previous instructions'

B'Injection detected. Input blocked.'

Csanitize

Duser_input

Attempts:

3 left

💡 Hint

Common Mistakes

Not checking for the exact injection phrase.

Returning unsafe input directly.

Not sanitizing input before use.

Check if the injection phrase is in input, return a warning, else sanitize input before processing.

Practice

1. What is the main purpose of prompt injection defense in AI systems?

easy

A. To protect AI from harmful or tricky user inputs

B. To improve AI's speed in processing data

C. To increase the size of the AI model

D. To reduce the cost of running AI models

Solution

1. Step 1: Understand the role of prompt injection defense

   Prompt injection defense is designed to stop harmful or tricky inputs from confusing or misguiding the AI.

2. Step 2: Compare options with this purpose

   Only To protect AI from harmful or tricky user inputs matches this goal; others relate to speed, size, or cost, which are unrelated.

3. Final Answer:

   To protect AI from harmful or tricky user inputs -> Option A

4. Quick Check:

   Purpose of prompt injection defense = Protect AI inputs [OK]

Hint: Focus on defense meaning protection from bad inputs [OK]

Common Mistakes:

• Confusing defense with performance improvement
• Thinking it changes AI model size
• Assuming it reduces costs

2. Which of the following is a correct way to implement a simple prompt injection defense filter in Python?

easy

A. if user_input = 'DROP TABLE': block_request()

B. if 'DROP TABLE' in user_input.upper(): block_request()

C. if user_input.contains('DROP TABLE'): block_request()

D. if user_input == 'drop table': block_request()

Solution

1. Step 1: Check syntax for string containment in Python

   Python uses in to check if a substring exists in a string, and upper() helps catch case differences.

2. Step 2: Evaluate each option's correctness

   if 'DROP TABLE' in user_input.upper(): block_request() uses correct syntax and case normalization. if user_input = 'DROP TABLE': block_request() uses assignment instead of comparison. if user_input.contains('DROP TABLE'): block_request() uses a non-existent method contains. if user_input == 'drop table': block_request() checks exact lowercase match, missing case variations.

3. Final Answer:

   if 'DROP TABLE' in user_input.upper(): block_request() -> Option B

4. Quick Check:

   Use 'in' and upper() for case-insensitive check [OK]

Hint: Remember Python uses 'in' for substring checks [OK]

Common Mistakes:

• Using '=' instead of '==' for comparison
• Using non-existent string methods
• Ignoring case sensitivity in checks

3. Given the code below, what will be the output if user_input = "Please DROP TABLE users"?

def block_request():
    return "Blocked"

def process_input(user_input):
    if 'DROP TABLE' in user_input.upper():
        return block_request()
    return "Allowed"

print(process_input(user_input))

medium

A. SyntaxError

B. Allowed

C. Blocked

D. None

Solution

1. Step 1: Analyze the condition in process_input

   The input string uppercased is "PLEASE DROP TABLE USERS" which contains "DROP TABLE".

2. Step 2: Determine which branch runs

   Since the condition is true, block_request() is called, returning "Blocked".

3. Final Answer:

   Blocked -> Option C

4. Quick Check:

   Input contains 'DROP TABLE' -> Blocked [OK]

Hint: Check if uppercase input contains 'DROP TABLE' [OK]

Common Mistakes:

• Ignoring case and expecting 'Allowed'
• Thinking code has syntax errors
• Assuming function returns None by default

4. Identify the error in this prompt injection defense code snippet:

def check_input(text):
    if text.lower().find('delete'):
        return 'Blocked'
    return 'Allowed'

medium

A. The find method returns -1 if not found, so condition is wrong

B. Using lower() is incorrect for filtering

C. The function should return a boolean, not strings

D. The function is missing a parameter

Solution

1. Step 1: Understand find method behavior

   find returns the index of substring or -1 if not found. In Python, -1 is truthy, so condition fails.

2. Step 2: Explain why this causes wrong logic

   If 'delete' is not found, condition is true (wrong). It should check if result is not -1 explicitly.

3. Final Answer:

   The find method returns -1 if not found, so condition is wrong -> Option A

4. Quick Check:

   Check find() != -1 for correct condition [OK]

Hint: Remember find() returns -1 if substring missing [OK]

Common Mistakes:

• Assuming find() returns False when not found
• Ignoring that -1 is truthy in Python
• Thinking lower() is the error

5. You want to defend an AI prompt from injection attacks by blocking inputs containing any of these words: ['DROP', 'DELETE', 'SHUTDOWN']. Which code snippet correctly implements this defense?

hard

A. if user_input.upper() == 'DROP' or 'DELETE' or 'SHUTDOWN': block_request()

B. if all(word in user_input.upper() for word in ['DROP', 'DELETE', 'SHUTDOWN']): block_request()

C. if 'DROP' or 'DELETE' or 'SHUTDOWN' in user_input.upper(): block_request()

D. if any(word in user_input.upper() for word in ['DROP', 'DELETE', 'SHUTDOWN']): block_request()

Solution

1. Step 1: Understand the goal to block if any word is present

   We want to block if at least one of the words appears in the input.

2. Step 2: Evaluate each option's logic

   if any(word in user_input.upper() for word in ['DROP', 'DELETE', 'SHUTDOWN']): block_request() uses any() correctly to check presence of any word. if all(word in user_input.upper() for word in ['DROP', 'DELETE', 'SHUTDOWN']): block_request() requires all words, which is too strict. if 'DROP' or 'DELETE' or 'SHUTDOWN' in user_input.upper(): block_request() has incorrect syntax; it always evaluates to true due to or chaining. if user_input.upper() == 'DROP' or 'DELETE' or 'SHUTDOWN': block_request() compares whole input to each word incorrectly.

3. Final Answer:

   if any(word in user_input.upper() for word in ['DROP', 'DELETE', 'SHUTDOWN']): block_request() -> Option D

4. Quick Check:

   Use any() to check multiple keywords [OK]

Hint: Use any() to check if any keyword is in input [OK]

Common Mistakes:

• Using all() instead of any()
• Incorrect or chaining causing always true
• Comparing whole string instead of substring