Bug Bounty Reports Discussed How to become an XSS expert with renniepak
Mar 12, 2025
René de Sain, known as renniepak, is an experienced ethical hacker and full-time bug bounty hunter specializing in XSS. In this engaging discussion, he shares insights on the realities of bug bounty life, the significance of XSS, and his unique postMessage hunting techniques. René emphasizes the importance of workflow optimization using JavaScript bookmarklets and manual tools. He also delves into emerging threats in Web3 and the thrill of discovering access control vulnerabilities. His future goals include exploring backend targets and enhancing his research impact.
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Career Pivot From Music To Bug Bounty
- René de Sain moved from music school to QA, then to security and became a full-time bug bounty hunter three years ago.
- He transitioned after working at bol.com and running their bug bounty program before going independent.
Build A Financial Buffer First
- Save a financial buffer before quitting a salaried job to hunt full-time on bug bounties.
- Aim to cover many months of living costs so you can afford to fail and stay creative.
XSS Is Common But Often Blamed On Third Parties
- XSS remains the most common and lucrative bug class but often involves third-party causes like postMessage listeners.
- That dependency on third parties makes many XSS findings harder to get paid for.