Web Application Security Breach – IDOR Incident PIR - Real-World Case Study

Описание: A single missing authorization check exposed thousands of customers on WebApp.
Here’s the full end-to-end breakdown every tester must learn from 👇

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Incident Summary

Application: WebApp – E-commerce web application

Incident type: IDOR (Insecure Direct Object Reference)

Severity: SEV-1 Critical data breach

Duration: 6 hours

Exposed data: customer names, phone numbers, addresses, order history, card last-4 digits

Impact: 12,500 users potentially exposed, 342 confirmed illegal accesses



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What Actually Happened (E2E Attack Flow)

Attacker logged in using a normal customer account

Opened browser DevTools and noticed API call:
GET /api/v2/orders/54321

Attacker manually changed order IDs to: 54322, 54323, 54324…

Backend returned full order data of other customers

No 403 Forbidden response was enforced

Attacker harvested hundreds of customer orders before detection



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Technical Root Cause

Backend did not verify whether the logged-in user owned the order

Authorization middleware was missing in new API

Frontend restrictions were assumed as security

Code reviews missed access-control validation



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Why Testing Failed

Only happy-path UI tests were executed

No negative or abuse-case tests

No API-level authorization testing

No SAST / DAST security scans in CI pipeline

Same test user used across environments



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How It Was Detected

WAF detected unusual API spike

First customer complaint triggered escalation

Security team reproduced breach in 15 minutes



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Immediate Fixes

Vulnerable API was disabled

Hotfix added server-side userId ownership validation

All exposed tokens and sessions were rotated

Targeted penetration re-testing completed

New API authorization tests added to regression suite



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New Security Test Scenarios Added

User A tries to access User B’s order → Expect 403

Sequential orderId tampering attempts

Role-based access validation (Customer vs Admin)

Token reuse after logout → Expect 401

Invalid, negative, non-existent orderId tests



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What Testers Must Learn

Never trust frontend security

Always test APIs directly

Authorization is mandatory for every endpoint

Abuse-case automation is as important as happy paths

Multi-user testing must be standard practice



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Final Takeaway

This breach was preventable.
Smart testers turn real attacks into permanent protection.
If your regression doesn’t include security abuse cases — your app is already at risk.


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