How to Use Codex for Bug Bounty Research Explore Broadly, Va...

[carlospolop]

🤖 Automated Content Update

This PR was automatically generated by the HackTricks News Bot based on a technical blog post.

📝 Source Information

• Blog URL: https://yeswehack.com/learn-bug-bounty/llm-series-codex
• Blog Title: How to Use Codex for Bug Bounty Research: Explore Broadly, Validate Rigorously
• Suggested Section: AI Security > Web Black-Box AI Pentester Bots and Burp MCP: LLM-assisted traffic review; cross-reference Pentesting Web > PostMessage Vulnerabilities and JWT Vulnerabilities

🎯 Content Summary

Overview

Published on September 3, 2026, the post evaluates Codex as an agentic environment for authorised vulnerability research. It covers black-box testing, source-assisted review, multi-agent hypothesis management and evidence-based exploit validation. Two PortSwigger mystery labs provide reproducible technical examples: a cross-origin postMessage DOM XSS and a server-side JWT authentication bypass using kid path traversal to /dev/null. No CV...

🔧 Technical Details

Cross-origin postMessage DOM XSS: A message listener that consumes e.data without validating e.origin allows an attacker-controlled page to reach its sinks. If URL validation merely searches for http: or https: rather than parsing the value and allowlisting its scheme, submit a value such as javascript:print()//http:. The required substring passes the check while remaining in a JavaScript comment, and assignment to location.href executes the payload in the target origin. A delivery page can frame the target and invoke iframe.contentWindow.postMessage(payload, '*'). Validate the complete victim workflow and final application state rather than treating an intermediate redirect as proof.

JWT key-selection path traversal: When a JWT verifier uses the attacker-controlled kid header to build a filesystem path for an HMAC key, test whether tra...

🤖 Agent Actions

Updated HackTricks in two files:

• src/AI/AI-Burp-MCP.md

  • Corrected Burp MCP proxy JAR name and direct SSE port.
  • Added Playwright-through-Burp MCP configuration.
  • Added an evidence-driven replay, hypothesis tracking, and validation workflow.
  • Cross-linked PostMessage and JWT technique pages.

• src/pentesting-web/postmessage-vulnerabilities/README.md

  • Added the javascript:print()//http: substring-validation bypass and iframe PoC.

The JWT kid traversal to /dev/null was already documented, so it was not duplicated. The undisclosed WordPress chain was omitted because it is not reproducible.

Validation passed with git diff --check, internal-link checks, citation numbering checks, and forbidden-source checks. mdbook was unavailable locally.

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This PR was automatically created by the HackTricks Feed Bot. Please review the changes carefully before merging.

[carlospolop]

🔗 Additional Context

Original Blog Post: https://yeswehack.com/learn-bug-bounty/llm-series-codex

Content Categories: Based on the analysis, this content was categorized under "AI Security > Web Black-Box AI Pentester Bots and Burp MCP: LLM-assisted traffic review; cross-reference Pentesting Web > PostMessage Vulnerabilities and JWT Vulnerabilities".

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• MD Files Formatting: 998 files processed

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Bot Version: HackTricks News Bot v1.0