Episode 58: Youssef Sammouda - Client-Side & ATO War Stories
Critical Thinking - Bug Bounty Podcast15 Helmi 2024

Episode 58: Youssef Sammouda - Client-Side & ATO War Stories

Episode 58: In this episode of Critical Thinking - Bug Bounty Podcast we finally sit down with Youssef Samouda and grill him on his various techniques for finding and exploiting client-side bugs and postMessage vulnerabilities. He shares some crazy stories about race conditions, exploiting hash change events, and leveraging scroll to text fragments.

Follow us on twitter at: @ctbbpodcast

We're new to this podcasting thing, so feel free to send us any feedback here: info@criticalthinkingpodcast.io

Shoutout to YTCracker for the awesome intro music!

------ Links ------

Follow your hosts Rhynorater & Teknogeek on twitter:

https://twitter.com/0xteknogeek

https://twitter.com/rhynorater

------ Ways to Support CTBBPodcast ------

Sign up for Caido using the referral code CTBBPODCAST for a 10% discount.

Hop on the CTBB Discord at https://ctbb.show/discord!

We also do Discord subs at $25, $10, $5 - premium subscribers get access to private masterclasses, exploits, tools, scripts, un-redacted bug reports, etc.

Today’s Guest: https://twitter.com/samm0uda?lang=en

https://ysamm.com/

Resources:

Client-side race conditions with postMessage:

https://ysamm.com/?p=742

Transferable Objects

https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Transferable_objects

Every known way to get references to windows, in javascript:

https://bluepnume.medium.com/every-known-way-to-get-references-to-windows-in-javascript-223778bede2d

Youssef’s interview with BBRE

https://www.youtube.com/watch?v=MXH1HqTFNm0

Timestamps:

(00:00:00) Introduction

(00:04:27) Client-side race conditions with postMessage

(00:18:12) On Hash Change Events and Scroll To Text Fragments

(00:32:00) Finding, documenting, and reporting complex bugs

(00:37:32) PostMessage Methodology

(00:45:05) Youssef's Vuln Story

(00:53:42) Where and how to look for ATO vulns

(01:05:21) MessagePort

(01:14:37) Window frame relationships

(01:20:24) Recon and JS monitoring

(01:37:03) Client-side routing

(01:48:05) MITMProxy

Jaksot(161)

Episode 121: Slonser’s Image Injection 0-day -> ATO & New Caido Collab Plugin

Episode 121: Slonser’s Image Injection 0-day -> ATO & New Caido Collab Plugin

Episode 121: In this episode of Critical Thinking - Bug Bounty Podcast we cover so much news and research that we ran out of room in the description...Follow us on XShoutout to YTCracker for the aweso...

8 Touko 202557min

Episode 120: SpaceRaccoon - From Day Zero to Zero Day

Episode 120: SpaceRaccoon - From Day Zero to Zero Day

Episode 120: In this episode of Critical Thinking - Bug Bounty Podcast Justin Gardner welcomes Eugene to talk (aka fanboy) about his new book, 'From Day Zero to Zero Day.' We walk through what to expe...

1 Touko 20251h 36min

Episode 119: Abusing Iframes from a client-side hacker

Episode 119: Abusing Iframes from a client-side hacker

Episode 119: In this episode of Critical Thinking - Bug Bounty Podcast Justin does a mini deep dive into the world of iframes, starting with why they’re significant, their attributes, and how to attac...

17 Huhti 202533min

Episode 118: Hacking Happy Hour: 0days on Tap and SQLi Shots

Episode 118: Hacking Happy Hour: 0days on Tap and SQLi Shots

Episode 118: In this episode of Critical Thinking - Bug Bounty Podcast we cover a host of news, including clientside tidbits, “Credentialless” iframes, prototype pollution, and what constitutes a poly...

10 Huhti 202558min

Episode 117: Hacking AI Series: Vulnus ex Machina - Part 1

Episode 117: Hacking AI Series: Vulnus ex Machina - Part 1

Episode 117: In this episode of Critical Thinking - Bug Bounty Podcast Joseph introduces Vulus Ex Machina: A 3-part mini-series on hacking AI applications. In this part, he lays the groundwork and foc...

3 Huhti 202532min

Episode 116: Auth Bypasses and Google VRP Writeups

Episode 116: Auth Bypasses and Google VRP Writeups

Episode 116: In this episode of Critical Thinking - Bug Bounty Podcast Justin gives a quick rundown of Portswigger’s SAML Roulette writeup, as well as some Google VRP reports, and a Next.js middleware...

27 Maalis 202526min

Episode 115: Mentee to Career Hacker - Mokusou (So Sakaguchi)

Episode 115: Mentee to Career Hacker - Mokusou (So Sakaguchi)

Episode 115: In this episode of Critical Thinking - Bug Bounty Podcast Justin and So Sakaguchi sit down to walk through some recent bugs, before having a live mentorship session. They also talk about ...

20 Maalis 20251h 40min

Episode 114: Single Page Application Hacking Playbook

Episode 114: Single Page Application Hacking Playbook

Episode 114: In this episode of Critical Thinking - Bug Bounty Podcast we’re diving into SPA and how to attack them.We also cover a host of news items, including some bug write-ups, AI updates, and a ...

13 Maalis 20251h 22min