Choongwoo Han
Senior Software Engineer at Databricks
Seattle, Washington, United States
Summary
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Rockstar🎓
Top SchoolChoongwoo Han is a Senior Software Engineer with 11 years of experience in systems, security, and developer tools, now based in Seattle and currently at Databricks after several engineering roles at Microsoft. He blends low-level performance work—optimizing a Rust-based JavaScript engine and improving bytecode execution—with security research, having authored PoC exploits for JS engine CVEs. His open-source contributions include .NET bindings and hooks for the widely-used Unicorn CPU emulator and deep fixes in the Boa project, demonstrating both pragmatic systems engineering and security-informed thinking. Trained at KAIST and UNIST, he has a history of shipping production-grade distributed model serving and fuzzing/static analysis tooling, making him comfortable across C++, Python, Rust, and cloud-native stacks. Notably, he often surfaces subtle performance wins (e.g., table-jump bytecode dispatch) and practical GC/hook fixes that improve long-running tooling stability.
11 years of coding experience
7 years of employment as a software developer
Bachelor of Science (BS) Computer Engineering, Bachelor of Science (BS) Computer Engineering at Ulsan National Institute of Science and TechnologyMaster's Degree Compuser Science, Master's Degree Compuser Science at Korea Advanced Institute of Science and Technology
Korean, English
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (31)
parserator10
javascript10
parser10
net10
v810
cpu10
dotnet10
interpreter10
chakra10
asp-net10
exploit10
rust-crates10
chakracore10
javascript-engine10
crate10
Programming languages (13)
Github contributions (5)
tunz/js-vuln-db
Aug 2016 - Sep 2019
A collection of JavaScript engine CVEs with PoCs
Role in this project:
Security Engineer
Security EngineerContributions:138 commits, 33 PRs, 125 pushes in 3 years 1 month
Contributions summary:Choongwoo primarily contributed proof-of-concept (PoC) code and exploit examples related to JavaScript engine vulnerabilities. Their commits focus on adding and demonstrating exploits for various CVEs affecting JavaScript engines like V8 and ChakraCore. These contributions showcase the user's ability to analyze and reproduce security vulnerabilities, providing valuable insights into the workings of JavaScript engines and the nature of associated exploits.
javascript-enginepocsjssecurityjavascript
unicorn-engine/unicorn
Oct 2015 - May 2023
Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, PowerPC, RiscV, S390x, TriCore, X86)
Role in this project:Back-end Developer
Back-end DeveloperContributions:3 reviews, 8 PRs, 8 comments in 7 years 8 months
Contributions summary:Choongwoo primarily contributed to the .NET bindings for the Unicorn engine. Their work involved setting up hooks for different events, including code, block, interrupt, memory read/write and memory access. They also addressed issues related to garbage collection and made improvements to the hook signatures. Further contributions include supporting HookDel with native bindings calls.
emulatorglibcarm64cpus390x
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