What caused the sudden spike in failed login attempts for Trade Republic's mobile app last week?

Introduction

The sudden spike in failed login attempts for Trade Republic's mobile app last week is a critical issue that demands immediate attention and thorough analysis. As we delve into this problem, we'll employ a systematic approach to identify, validate, and address the root cause while considering both short-term fixes and long-term implications for the product and user experience.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this could be related to a recent app update. Has there been any significant changes or updates to the app in the past week or two?

Why it matters: Recent changes often correlate with sudden spikes in issues. Expected answer: Yes, there was an update released last week. Impact on approach: If confirmed, we'd focus on changes in that update.

• Considering user segments, I'm wondering if this is affecting all users equally. Are we seeing this spike across all user segments or is it concentrated in specific groups?

Why it matters: Helps narrow down potential causes and affected user base. Expected answer: The issue is more prevalent among Android users. Impact on approach: We'd prioritize investigating Android-specific factors.

• Given the nature of the issue, I'm curious about any changes in authentication systems. Have there been any modifications to our login or authentication processes recently?

Why it matters: Authentication changes could directly impact login success rates. Expected answer: No recent changes to authentication systems. Impact on approach: We'd look more closely at client-side issues or external factors.

• Thinking about potential external factors, has there been any unusual activity or reports from our security team about potential attacks or breaches?

Why it matters: Rules out or confirms security-related causes. Expected answer: No significant security alerts reported. Impact on approach: We'd focus more on technical or user behavior issues.