Jonas Lejon
Senior Cyber Security Specialist at Defentry
Sweden
Summary
🤩
RockstarJonas Lejon is a Senior Cyber Security Specialist based in Sweden with over a decade of focused professional experience and a career spanning three decades of involvement in advanced cyber security practices. He currently leads security work at Triop AB, chairs the Internet Society Swedish Chapter, and advises security companies like Holm Security while founding and running niche ventures such as WPSec WordPress Security Scanner. His background includes roles in national defense and intelligence-related IT security (Swedish Armed Forces, FRA), giving him deep operational and adversary-aware expertise beyond typical enterprise security. Jonas combines hands-on technical depth with board-level strategic insight and early-stage investing in security startups, reflecting both practitioner rigor and an entrepreneurial mindset. An underappreciated strength is his sustained commitment to the Swedish internet and security ecosystem, evidenced by long-term governance roles and local stewardship.
11 years of coding experience
2 years of employment as a software developer
Stackoverflow
3,229reputation
1.1mreached
19answers
8questions
gzip
top-1%
php
top-5%
jquery
top-5%
encoding
top-1%
html
top-5%
Github Skills (200)
burp10
shodan10
rsa10
encoding10
command-line-tool10
scanner10
pentesting10
scraper10
signature10
administration10
python10
waf10
web-application-security10
twitter10
infosec10
Programming languages (15)
Github contributions (5)
jonaslejon/tor-fingerprint
May 2016 - Sep 2018
Contributions:5 commits, 4 pushes in 2 years 3 months
jonaslejon/malicious-pdf
Aug 2021 - Sep 2022
đź’€ Generate a bunch of malicious pdf files with phone-home functionality. Can be used with Burp Collaborator or Interact.sh
Contributions:1 review, 24 commits, 10 PRs in 1 year 1 month
pythonpenetration-testbugbountypdf-generationburp
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