Offensive Security Specialist

Building & Breaking
Secure Systems

Penetration testing that finds what automated scanners miss. Manual exploitation, business logic flaws, and actionable remediation for organizations that demand real security.

View Services
50+
Security Assessments
200+
Vulnerabilities Found
15+
Enterprise Clients
100%
Confidential
pentest@kali:~
$ ./recon.sh --target $CLIENT
[*] Starting reconnaissance...
[+] Discovered 23 subdomains
[+] Found 8 exposed endpoints
$ nuclei -t cves/ -severity critical,high
[!] CVE-2024-XXXX detected
[+] Auth bypass vulnerability found
$ python3 exploit.py --verify
[βœ“] Exploitation successful - Access gained
[*] Generating report...
$

Theodoros Moutesidis

Penetration Tester | Security Researcher | Offensive Security Specialist

I'm a penetration tester specializing in identifying vulnerabilities that automated tools miss. My methodology combines manual testing expertise with deep technical knowledge to uncover complex web application flaws, business logic errors, and chained attack vectors that require human intuition to discover.

Enterprise & Government

Conducted penetration testing engagements for government institutions and large enterprises, assessing critical infrastructure, internal networks, and sensitive web applications. Experience working within strict compliance frameworks and delivering detailed reports to executive stakeholders.

European Projects

Contributed to EU-funded cybersecurity initiatives, performing security assessments on cross-border digital platforms and research infrastructure. Collaborated with international teams to evaluate security postures and implement hardening measures for multi-national deployments.

Penetration Testing Focus

Specializing in web application penetration testing, network infrastructure assessments, and Active Directory security reviews. My approach emphasizes manual testing techniques, attack path chaining, and identifying vulnerabilities that scanners overlook.

Security Research

Currently exploring Offensive AI Research, developing autonomous agent frameworks that leverage large language models for intelligent vulnerability discovery and multi-step attack simulation. Building custom security tools for specialized assessments.

What I Offer

Comprehensive penetration testing services to identify and eliminate your organization's attack surface.

Web Application Penetration Testing

Manual, methodology-driven testing to identify OWASP Top 10 vulnerabilities, authentication bypasses, and business logic errors.

2-4 weeks
Learn more β†’

Internal & External Network Assessments

Comprehensive network security evaluations including Active Directory attacks and lateral movement analysis.

1-3 weeks
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Security Automation & Tool Development

Custom tooling and automation to accelerate vulnerability discovery and enhance security operations.

2-6 weeks
Learn more β†’

Research & Tools

Open-source tools and research pushing the boundaries of offensive security.

Open Source

jsrip

A reconnaissance tool designed to scrape and analyze client-side JavaScript files for hidden API endpoints, hardcoded secrets, and sensitive data exposure. Automates the tedious process of JavaScript analysis during web application assessments.

JavaScript Analysis Reconnaissance Secret Detection API Discovery
View on GitHub
R&D

Agentic Pentesting Framework

Pioneering research leveraging Large Language Models and "Chain-of-Thought" reasoning for intelligent, multi-step attack simulation. Autonomous agents capable of contextual decision-making, vulnerability chaining, and adaptive exploitation strategies.

LLM Agents Chain-of-Thought Attack Simulation Offensive AI

Background & Expertise

Professional experience, technical skills, and industry certifications.

Freelance Penetration Tester

Independent
Current

Full-cycle security assessments for large-scale Greek organizations. From scoping to executive reporting.

Penetration Tester

Chubb
Current

Manual web app testing and custom security automation for enterprise systems.

Bug Hunter

Synack Red Team
Ongoing

Elite vetted researcher finding high-severity vulnerabilities in Fortune 500 programs.

DevSecOps Engineer

European Dynamics
Previous

CI/CD security integration, container hardening, and infrastructure-as-code practices.

System Administrator

INSPOT
Previous

Enterprise infrastructure management, network security, and incident response.

Offensive Security

Manual Exploitation Expert
Bug Hunting Expert
Web App Security Advanced
AD Attacks Advanced
Privilege Escalation Advanced

Security Tools

Burp Suite Pro Expert
Nmap Advanced
Metasploit Advanced
BloodHound Advanced
Nuclei Proficient
Impacket Advanced

Development

Python Expert
JavaScript Proficient
Bash Advanced
Security Automation Advanced

Infrastructure

Linux Advanced
Docker Proficient
Cloud Security Proficient
CI/CD Security Advanced

OSCP

Offensive Security Certified Professional

Achieved

CWES

Certified Web Exploitation Specialist

Achieved

CRTA

Certified Red Team Analyst

Achieved

OSWE

Offensive Security Web Expert

In Progress

Let's Discuss Your Security

Ready to identify vulnerabilities in your systems before attackers do? Get in touch.

Ready to Secure Your Systems?

Whether you need a full penetration test, security consultation, or want to discuss your organization's security postureβ€”I'm here to help.