Julien Voisin
Security Consultant at Casaba Security
France
Summary
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RockstarJulien Voisin is a security consultant with 15 years of hands-on experience hardening software and fixing vulnerabilities across diverse open-source ecosystems. Based in France and currently at Casaba Security, he brings deep C and systems expertise evidenced by contributions to projects like radare2, hardened_malloc and OSS-Fuzz, where he strengthened memory safety and fuzzing coverage. Julien blends backend engineering and security work—from improving FFmpeg integration and session hardening in web apps to adding YARA-based signature scanning and refining malware detection rules. He routinely moves between low-level debugging (memory leaks, off-by-ones) and pragmatic application fixes (cookie hardening, accessibility), showing a rare full-stack security mindset. Colleagues benefit from his forensic approach to bugs and his habit of turning noisy warnings and false positives into actionable, maintainable code improvements.
15 years of coding experience
French, English, German, Sign languages
Github Skills (97)
penetration-testing10
wordpress-themes10
python10
web-application-security10
testing10
c1110
aiff10
security10
c1710
vim10
ui-theme10
malware10
code-auditing10
audit-logging10
webextension10
Programming languages (41)
Github contributions (5)
jvoisin/php-malware-finder
May 2015 - Aug 2021
Detect potentially malicious PHP files
Role in this project:
Security Engineer
Security EngineerContributions:1 release, 5 reviews, 82 commits in 6 years 3 months
Contributions summary:Julien primarily focused on improving the effectiveness of a PHP malware detection tool. Their contributions involved refining existing YARA rules to improve accuracy and efficiency by removing false positives and speeding up rule execution. They added new rules to detect various malicious patterns, including obfuscated code, and integrated a whitelist system to reduce false positives. Additionally, the user added a Python script for scanning files, and implemented filesize checks to improve the performance of the tool.
phpyaramalwarewebshellantivirus
airsonic/airsonic
Mar 2019 - Aug 2021
:satellite: :cloud: :notes:Airsonic, a Free and Open Source community driven media server (fork of Subsonic and Libresonic)
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:219 commits, 311 PRs, 125 pushes in 2 years 5 months
Contributions summary:Julien primarily contributed to front-end development by removing outdated JavaScript libraries like MomentJS and pngfix, and updating MediaElement.js. They also fixed JavaScript errors and implemented UI improvements. The contributions demonstrate a focus on modernizing the codebase and improving the user experience by replacing legacy components with contemporary alternatives and ensuring UI stability.
notesaudio-streamingsatelliteairsonicdlna
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