Mario E. Mejia Lezama
Specializing in web application security, penetration testing, and vulnerability research
About Me
I am an Offensive Security Engineer with a solid background in Security Penetration Testing, Vulnerability Research & Bug Bounty Hunting. Recognized as Mexico and Central America's top-ranked hacker for 4 consecutive years on HackerOne. My independent security research has led to significant industry recognition, including being selected as a main stage speaker at BugCon Mexico 2024.
Over the course of my career, I've successfully identified and reported more than 200 vulnerabilities, demonstrating expertise in web applications, APIs, Artificial Intelligence Systems, LLM's and cloud security.
Skills & Expertise
Professional Experience
Offensive Security Engineer
2022 - PresentLeading offensive security initiatives at dLocal, specializing in penetration testing, threat hunting, and incident response. Coordinated and executed security engagements involving comprehensive vulnerability assessments.
Key Achievements:
- Led offensive security operations for global payment platform
- Implemented advanced threat hunting methodologies
- Developed security controls and incident response procedures
- Mentored junior security professionals
Security Penetration Tester
2021 - 2022Conducted comprehensive security assessments for Tripadvisor, focusing on web applications, APIs, and cloud infrastructure.
Key Achievements:
- Performed extensive penetration testing engagements
- Identified critical vulnerabilities in production systems
- Provided detailed remediation guidance
- Enhanced security incident response capabilities
Security Researcher
2019 - PresentIndependent security researcher and bug bounty hunter on HackerOne platform. Recognized as Mexico and Central America's top-ranked hacker for 4 consecutive years.
Key Achievements:
- Discovered 200+ security vulnerabilities
- Top ranked on HackerOne Mexico Leaderboard 2021-2024
- Main stage speaker at BugCon Mexico 2024
- Published multiple technical writeups and research
Awards & Achievements
1st Place at BugCon Live Hacking Event - 2022
Sep 2022BugCon Mexico organized a live hacking event hosted by Mercado Libre, competing against the best hackers in Mexico. Demonstrated exceptional skills in vulnerability discovery and exploitation techniques.
1st Place at BugCon Live Hacking Event - 2021
Sep 2021Secured first place in BugCon Mexico's live hacking competition, showcasing advanced penetration testing skills and innovative vulnerability discovery techniques against Mercado Libre's assets.
Top Ranked Hacker - HackerOne Mexico
2021 - 2024Recognized as Mexico and Central America's top-ranked hacker for 4 consecutive years on HackerOne platform, demonstrating unparalleled dedication to cybersecurity excellence and research.
Latest Writeups
Exposing PII and SSNs through Persistent Session Tokens
2024
How I Accessed Microsoft's ServiceNow
2024
Latest Posts
Get In Touch
Let's Connect
Interested in security research, bug bounty programs, or collaboration opportunities? Feel free to reach out!
