ChangSeok Oh
Open Source Hacker | Software Engineer | Security Researcher

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Open-source hacker and security researcher specializing in web and computer systems. A WebKit, Chromium, and GNOME project contributor. 10 years of industry and 7 years of academic experience. Interested in opportunities in the Web browser, Emerging Web, Browser Security, Web Security & Privacy, and Computer Graphics.
Research Interest
Web Security & Privacy, Emerging Web, System Security, Computer Graphics
Education
08/2017 - 12/2022
Ph.D. Student (ABD) in Computer Science, Georgia Institute of Technology, U.S.A.
08/2017 - 12/2022
Dual M.S. in Computer Science and Cybersecurity, Georgia Institute of Technology, U.S.A.
03/2000 - 07/2008
Dual B.E. in Digital Media and Computer Engineering, Ajou University, South Korea
Professional Experience
01/2023 - Present
Sr. Software Engineer at ByteDance/TikTok Inc.
  • Working on the Web Platform
  • Web Standardization at the W3C CSS Working Group
  • Implement WebGPU in an in-house rendering engine
06/2019 - 12/2022
Intern at Igalia S.L. (cert.)
  • Bring ANGLE backend for WebGL to WebKitGTK
  • Zero copy texture sharing between Mesa and ANGLE via Linux DMA buffer
  • Research and implement Text-To-Speech for WebKitGTK
05/2020 - 08/2020
05/2019 - 08/2019
Intern at Samsung Research America
  • Build a web app for health data analysis with ReactJS (frontend) and Node.js (backend)
  • Built an automated system verifying the UI of a watch app by using the Tizen automation framework
  • Profiled memory usage and revealed possible memory leak of a watch app by using Valgrind
  • Implemented file transfer via Bluetooth LE in a React Native watch application
08/2012 - 03/2016
Software engineer at Collabora Ltd.
  • Developed hardware based compositing based on Clutter in WebKit
  • Resource efficient web browser based on GNOME Epiphany for Raspberry Pi 2+
  • Customized WebKit features and API set for Smart TV Alliance SDK
07/2008 - 08/2012
Assistant Software engineer at Samsung Electronics
  • Developed an in-house web layout engine for Smart TVs and printers in C++
  • Implemented WebGL and Accelerated Compositing in WebKit EFL by using OpenGL ES for Tizen
07/2007 - 06/2008
Intern at Samsung Software Memembership
  • Developed a 3D racing game using DirectX on Windows (video)
Academic Experience
01/2023 - 08/2023
Instructional Associate at OMSCS, Georgia Tech
  • CS 6262: Network Security
05/2021 - 08/2021
Research Intern at Tandon School of Engineering, NYU
  • Explore online ad privacy issues
08/2019 - 12/2022
Teaching Assistant at the School of Computer Science, Georgia Tech
  • CS 6262: Network Security, Design and Implement the XSS task using node.js and Chrome Extension
  • CS 6035: Intro to InfoSec
07/2016 - 05/2022
Research Assistant at the School of Computer Science, Georgia Tech
  • Study privacy leakage in online ads
  • Redesign chromium to block user tracking by web browser fingerprints
  • Debloat chrome browser with feature sunsetting on the fly by binary rewriting
  • Developed a defense system against micro DDoS by profiling resources with HPC (Intel PCM, MBM)
  • Implemented an idle profiler that diagnoses off-CPU time in the multi-threaded programs using HPC
Open Source Projects
10/2023 - Present
Committer to Chromium/Blink (patch set 1, 2)
04/2013 - Present
Committer to WebKit (patches)
  • Contributed CSS properties: font-size-adjust with two-value syntax, text-decoration-thickness: <length-percentage>
  • Contributed several web features for WebKitGTK: Form Validation with native widgets, Gamepad API with libmanette, AVIF support with dav1d, Speech Synthesis (i.e., Text-to-Speech) with Flite, Speech Recognition (i.e., Speech-to-Text) with Whisper.cpp, etc.
  • Implemented OpenGL ES backend for Accelerated Compositing
  • Developed memory pressure handler that copes with out-of-memory on top of Linux cgroup
  • Enhanced WebGL support and Fix layout and rendering issues
  • Fixed CVE security bugs in WebKit (CVE-2020-10018, CVE-2020-11793)
10/2013 - Present
Member of GNOME foundation (patches)
  • Translate GNOME Web and its Help document in Korean
Publications
ACSAC 2022
DeView: Confining Progressive Web Applications by Debloating Web APIs (paper)
ChangSeok Oh, Sangho Lee, Chenxiong Qian, HyungJoon Koo, and Wenke Lee
ACM CCS 2022
Cart-ology: Intercepting Targeted Advertising via Ad Network Identity Entanglement (paper)
ChangSeok Oh, Chris Kanich, Damon McCoy, and Paul Pearce
ACM CCS 2020
Slimium: Debloating the Chromium Browser with Feature Subsetting (paper)
Chenxiong Qian, HyungJoon Koo, ChangSeok Oh, Taesoo Kim, and Wenke Lee
arXiv:2205.00056
Mitigating Low-volume DoS Attacks with Data-driven Resource Accounting (paper)
ChangSeok Oh, Sangho Lee, Wen Xu, Rohan Devang Vora, and Taesoo Kim
Patents
US9524076B2
US9378300B2
Interface method and display device (alias Picture-in-Picture Play)
Worldwide applications: KR101573332B1, EP2336909A3, CN102104618A
US20110090165A1
Interface method and display device
Worldwide applications: KR101630754B1
US20110289110A1
Talks
12/09/2022
ACSAC 2022 in Austin, TX, U.S.A.
DeView: Confining Progressive Web Applications by Debloating Web APIs (slides)
11/09/2022
ACM CCS 2022 in Los Angeles, CA, U.S.A.
Cart-ology: Intercepting Targeted Advertising via Ad Network Identity Entanglement (slides)
12/07/2014
Web Engines Hackfest 2014 in A Coruña, Spain
Raspberry Pi Browser by changseok & kov (slides)
09/29/2014
DEVIEW 2014 in Seoul, South Korea
Lessons from developing a web browser for Raspberry Pi (slides, video)
04/25/2014
Jeju University in Jeju, South Korea
Introduction to GNOME (slides)
10/27/2013
DevOn 2013 in Seoul, South Korea
GNOME & You (slides)
Services
04/2023 - Present
10/2021