Lab 5
Level 1 - Beginner
OTP Logic Weakness Lab
Level 1 Authentication simulation: learn how predictable or poorly designed OTP logic weakens account verification.
Beginner
Authentication • 20 min
Learning Objectives
This lab is a controlled simulation only. No real backend or dangerous code execution is used.
Objective 1
Review a fake OTP flow and spot a predictable code pattern.
Objective 2
Understand why sequential or reusable OTPs weaken second-factor verification.
Objective 3
Learn why OTPs must be random, short-lived, and bound to a specific session.
Challenge Area
Use the input fields below to safely simulate the vulnerable behavior.
Predicted OTP
Fake OTP Verification Flow
Last issued code: 123455
Observed weakness: codes appear sequential
Submitted OTP: (none yet)
Result Panel
Review the fake OTP flow and enter the likely valid code. The lab succeeds when the guess matches the weak predictable pattern.
Hints
Reveal them progressively if you get stuck.
Click the hint button to reveal progressive guidance.