Authentication vulnerability testing in Testing Fundamentals - Test Execution Trace

Test Overview

This test checks if the login page properly blocks access when wrong credentials are used. It verifies that the system does not allow unauthorized users to log in.

Test Code - Selenium with Python unittest

Testing Fundamentals

import unittest
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

class TestAuthenticationVulnerability(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com/login')

    def test_invalid_login(self):
        driver = self.driver
        # Wait for username field
        WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, 'username')))
        username_input = driver.find_element(By.ID, 'username')
        password_input = driver.find_element(By.ID, 'password')
        login_button = driver.find_element(By.ID, 'login-btn')

        # Enter invalid credentials
        username_input.send_keys('wronguser')
        password_input.send_keys('wrongpass')
        login_button.click()

        # Wait for error message
        error_element = WebDriverWait(driver, 10).until(
            EC.presence_of_element_located((By.ID, 'error-msg'))
        )

        # Verify error message text
        self.assertEqual(error_element.text, 'Invalid username or password.')

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

Execution Trace - 8 Steps

Step	Action	System State	Assertion	Result
1	Test starts and opens Chrome browser	Browser is open at 'https://example.com/login' page showing login form with username, password fields and login button	—	PASS
2	Waits until username input field is present	Login form is fully loaded with username input visible	Username input field is present	PASS
3	Finds username, password input fields and login button	All required elements located by their IDs	Elements found successfully	PASS
4	Enters invalid username 'wronguser' and password 'wrongpass'	Input fields filled with invalid credentials	—	PASS
5	Clicks the login button	Login form submitted, page processes login attempt	—	PASS
6	Waits for error message element with ID 'error-msg' to appear	Error message displayed on page	Error message element is present	PASS
7	Checks that error message text equals 'Invalid username or password.'	Error message text visible to user	Error message text matches expected	PASS
8	Test ends and browser closes	Browser closed, test complete	—	PASS

Failure Scenario

Failing Condition: Error message element does not appear after submitting invalid credentials

Execution Trace Quiz - 3 Questions

What does the test verify after clicking the login button with wrong credentials?

A That the user is redirected to the homepage

B That the password field is cleared

C That an error message saying 'Invalid username or password.' appears

D That the login button is disabled

Key Result

Always wait explicitly for elements that appear after actions, like error messages, to avoid flaky tests and ensure the application properly handles invalid inputs.

Practice

1. What is the main goal of authentication vulnerability testing?

easy

A. To ensure only authorized users can access the system

B. To check the system's speed under heavy load

C. To verify the user interface design

D. To test database backup procedures

Solution

1. Step 1: Understand authentication testing purpose

   Authentication testing focuses on verifying that only real, authorized users can access the system.

2. Step 2: Eliminate unrelated options

   Options about speed, UI, or backups do not relate to authentication vulnerabilities.

3. Final Answer:

   To ensure only authorized users can access the system -> Option A

4. Quick Check:

   Authentication goal = authorized access [OK]

Hint: Authentication testing checks who can enter the system [OK]

Common Mistakes:

• Confusing authentication with performance testing
• Thinking authentication tests UI elements
• Mixing authentication with data backup checks

2. Which of the following is a correct way to test for weak password acceptance during authentication?

easy

A. Try logging in with a password like 12345

B. Check if the system allows SQL queries in the username field

C. Test if the login page loads within 2 seconds

D. Verify if the password reset email is sent

Solution

1. Step 1: Identify weak password test

   Testing weak passwords means trying simple, common passwords like '12345' to see if the system accepts them.

2. Step 2: Differentiate from other tests

   Options about SQL injection, performance, or email sending are different security or functionality tests.

3. Final Answer:

   Try logging in with a password like 12345 -> Option A

4. Quick Check:

   Weak password test = simple password try [OK]

Hint: Use simple passwords to check weak password acceptance [OK]

Common Mistakes:

• Confusing weak password test with SQL injection test
• Testing page speed instead of authentication strength
• Mixing password reset with password strength testing

3. Consider this pseudocode for testing login lockout:

attempts = 0
while attempts < 5:
    login('user', 'wrongpass')
    attempts += 1
result = login('user', 'correctpass')

What should result be if the system locks the account after 5 failed attempts?

medium

A. Login successful

B. Account locked error

C. Password reset prompt

D. System crash

Solution

1. Step 1: Understand lockout after failed attempts

   After 5 wrong tries, the system should lock the account to prevent further access.

2. Step 2: Analyze final login attempt

   Even with the correct password, the account is locked, so login should fail with an account locked error.

3. Final Answer:

   Account locked error -> Option B

4. Quick Check:

   Lockout after 5 fails = account locked error [OK]

Hint: After 5 fails, login should block even correct passwords [OK]

Common Mistakes:

• Expecting login success after lockout
• Confusing reset prompt with lockout error
• Assuming system crashes on failed login

4. You wrote this test to check multi-factor authentication (MFA):

login('user', 'correctpass')
// skip MFA step
access = check_access()

Why might this test fail to detect an authentication vulnerability?

medium

A. It uses the wrong username format

B. It checks access before login

C. It tests password reset instead of login

D. It skips the MFA step, so it doesn't test full authentication

Solution

1. Step 1: Identify skipped MFA step

   The test logs in with correct password but skips the MFA step, missing a critical security check.

2. Step 2: Understand impact on vulnerability detection

   Skipping MFA means the test won't catch if MFA is bypassed, leaving a vulnerability undetected.

3. Final Answer:

   It skips the MFA step, so it doesn't test full authentication -> Option D

4. Quick Check:

   Skipping MFA = incomplete authentication test [OK]

Hint: Always include MFA step to test full authentication [OK]

Common Mistakes:

• Ignoring MFA step importance
• Confusing username format with MFA issues
• Mixing login and password reset tests

5. You want to test if the system properly prevents session fixation attacks after login. Which test approach is best?

hard

A. Verify if password reset emails are sent promptly

B. Try logging in with an invalid password multiple times

C. Check if session ID changes after successful login

D. Test if the login page uses HTTPS

Solution

1. Step 1: Understand session fixation attack

   Session fixation means attacker forces a known session ID before login to hijack session.

2. Step 2: Identify test to prevent session fixation

   The system should assign a new session ID after login to prevent fixation.

3. Final Answer:

   Check if session ID changes after successful login -> Option C

4. Quick Check:

   Session fixation test = session ID change after login [OK]

Hint: Session ID must change after login to stop fixation [OK]

Common Mistakes:

• Confusing session fixation with password errors
• Testing unrelated password reset or HTTPS only
• Ignoring session ID behavior after login