Bounty life, with André Baptista

In this talk, André will show his journey, how to achieve the #bountylife, how live hacking events work and how to get invites. He will walk you through his best bugs and techniques, found during live hacking events and doing bug bounties.

Trusted Types and the end of DOM XSS, with Krzysztof Kotowicz

18 years have passed since Cross-Site Scripting (XSS) has been identified as a web vulnerability class. Since then, numerous efforts have been proposed to detect, fix or mitigate it. We’ve seen vulnerability scanners, fuzzers, static & dynamic code analyzers, taint tracking engines, linters, and finally XSS filters, WAFs and all various flavours of Content Security Policy.

Various libraries have been created to minimize or eliminate the risk of XSS: HTML sanitizers, templating libraries, sandboxing solutions – and yet XSS is still one of the most prevalent vulnerabilities plaguing web applications.

It seems like, while we have a pretty good grasp on how to address stored & reflected XSS, “solving” DOM XSS remains an open question. DOM XSS is caused by ever-growing complexity of client-side JavaScript code (see script gadgets), but most importantly – the lack of security in DOM API design.

But perhaps we have a chance this time? Trusted Types is a new browser API that allows a web application to limit its interaction with the DOM, with the goal of obliterating DOM XSS. Based on the battle-tested design that prevents XSS in most of the Google web applications, Trusted Types add the DOM XSS prevention API to the browsers. Trusted Types allow to isolate the application components that may potentially introduce DOM XSS into tiny, reviewable pieces, and guarantee that the rest of the code is DOM-XSS free. They can also leverage existing solutions like autoescaping templating libraries, or client-side sanitizers to use them as building blocks of a secure application.

Trusted Types have a working polyfill, an implementation in Chrome and integrate well with existing JS frameworks and libraries. Oddly similar to both XSS filters and CSP, they are also fundamentally different, and in our opinion have a reasonable chance of eliminating DOM XSS – once and for all.

About the Guests

André Baptista is a Professor at Master in Information Security in the University of Porto and Security researcher. He’s the captain of xSTF CTF team and the winner of the Most Valuable Hacker prize in a HackerOne live-hacking event in Washington DC, 2018. Bug Bounty hunter and C3P collaborator (Center of Competence in Cyber Security and Privacy) – University of Porto.

Krzysztof Kotowicz is an Information Security Engineer at Google and a panel member of Google’s Vulnerability Rewards Program. He’s a web security researcher specialized in JavaScript, browser extensions and client-side security. Author of multiple open-source pentesting tools, and recognized HTML5/UI redressing attack vectors. Speaker at international IT security conferences & meetings (Black Hat, BruCON, Hack In Paris, CONFidence, SecurityByte, HackPra, OWASP AppSec, Insomni’Hack).