I find and close security gaps before attackers can exploit them.
I'm Mattheos Tasios, a Cybersecurity Engineer specializing in penetration testing, vulnerability management, and network & infrastructure hardening. My background includes three years as a full-stack developer, giving me a practical, code-level understanding of the systems I secure.
Focus
Offensive Security
Toolkit
ZAP · Zeek · Volatility
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Years of experience
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Security assessments & audits
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Projects completed
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Systems hardened
Finding the gaps before attackers do
A computer science background and a genuine habit of trying to break systems before someone else does, now applied full-time to offensive and defensive security.
Focus
Security & Offensive Testing
whoami
Security engineering built on real development experience
I'm a Cybersecurity Engineer with a Computer Science degree, focused on penetration testing, network & infrastructure hardening, and SOC-style monitoring, i.e. finding and closing the gaps that put real systems at risk. My work spans web application vulnerability assessments, Active Directory and Linux hardening, and hands-on incident-response and forensics labs.
Before specializing in security, I spent three years as a full-stack developer building Java-powered backends and React frontends. That background still matters: I approach application security the way someone who has actually built production systems would, understanding not just where vulnerabilities exist, but why they were introduced and how to prevent them long-term.
Security-first, with development experience in the background
Offensive testing, infrastructure hardening, and continuous monitoring form the core of my technical focus, supported by a full-stack development background.
Penetration Testing
Hands-on offensive security: web application pentests, vulnerability assessments, and exploit validation using tools like Burp Suite, OWASP ZAP, and Metasploit to find weaknesses before attackers do.
Network & Infrastructure Hardening
Firewall configuration, network segmentation, Active Directory GPO hardening, and Linux OS hardening that shrink attack surface across an organization's infrastructure.
Security Monitoring & Threat Hunting
SOC-style log analysis, packet capture and traffic analysis with tools like Zeek and Wireshark, plus incident-response fundamentals to detect and triage threats fast.
Application Security
Secure authentication design, JWT and token security, and code-level reviews aimed at closing the gaps attackers actually exploit, informed by real full-stack build experience.
Background
Software Development
Full-stack development background in Java, React, and React Native that informs how I approach secure coding practices and application security reviews.
Frequently asked questions
Answers to what recruiters and hiring teams most often ask. Have another question? Reach out directly in the contact section.
My core focus areas are penetration testing and vulnerability assessment, network and infrastructure hardening (Active Directory, Linux, firewall/pfSense configuration), and security monitoring and threat detection. I also work on application security, including secure authentication design and code-level reviews.
Let's connect about cybersecurity engineering opportunities
I'm actively exploring full-time cybersecurity engineering roles. Feel free to reach out to connect, discuss an opportunity, or talk shop about security.