Tanuki

Jul 28, 2026 /2 min read /bugforgeidorbroken-access-control
johnmatrix Purple Teamer - AI security, offensive tooling about →
#bugforge#idor#broken-access-control#burpsuite#mcp
  • Today’s daily challenge is a straightforward one, but I used BurpSuite with MCP server to solve as it as I am trying to learn and understand the AI impact.

Daily

Enumeration

  • We get a landing page, so as usual we can register Daily2

  • The best way to check for web application vulnerabilities is to simply use it, not automatically search for them

  • Majority of the time, we can observe something out of the ordinary while simply clicking through and checking the responses from the application/server

Daily3

  • After browsing decks, we can add them to dashboard and Start Studying

  • This pretty much gives us all of the functionality of the website, we can continue now within BurpSuite

BurpSuite

  • Any time we see GET request and numbers within, it would be rude not to play around and check

Daily4

  • In this case, I approached it different … as I have my MCP connected to Burp, I used codex to help me solve this and see whether there is a good way to showcase AI usage.

MCP BurpSuite

  • I asked first to give me an idea whether it can find anything within the HTTP history of Burp, as I clicked around the page, based on the hint

Daily5

  • The suggestion was taken literally, so that one was on me :)
  • Next, I asked to dig deeper and see whether there is something meaningful that we can use
  • It was very adamant about the 42 Socket.IO event, I had to politely ask to change approach

Daily6

  • Since I have observed the API stats before with the GET, I redirected its brain there

Daily7

  • It was able to run tests and found the correct way to get the flag

Daily8

  • Thank you for reading, my first (of many to come) published writeup!
  • Keep Learning and Be Useful!

Security Takeaways

Impact

  • Unauthorized access to other users’ data via IDOR
  • Potential exposure of private content and user metadata
  • Demonstrates broken authorization logic

Vulnerability Classification

  • OWASP Top 10: Broken Access Control
  • Vulnerability Type: IDOR (Insecure Direct Object Reference)
  • CWE: CWE-639 - Authorization Bypass Through User-Controlled Key

Root Cause

The backend trusts client-controlled identifiers (e.g. resource IDs in GET requests) without verifying that the authenticated user is allowed to access the referenced object.

Remediation

  • Enforce server-side authorization checks on every object access
  • Validate ownership or access rights before returning data
  • Avoid using predictable, sequential IDs where possible
  • Add logging and alerting for unusual access patterns

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