Theklis Stefani

Junior Security Consultant

Theklis Stefani

Theklis is a Junior Security Consultant at Sentrium, specialising in web application penetration testing. His work involves testing real-world applications to identify and validate vulnerabilities, demonstrate potential exploit paths, and provide clients with practical recommendations to improve their security posture. Theklis holds an MSc in Cyber Security and certifications including PT1 (TryHackMe) and eJPT (INE Security).

Before moving into security, Theklis worked for two years as a software engineer, gaining a strong understanding of how developers think and how security fits into development processes. Over the past six months at Sentrium, Theklis has been performing web applications and API penetration tests across a range of sectors. He is driven by curiosity and the desire to understand how things work, enjoying the process of turning vulnerabilities into opportunities to make systems stronger and more resilient.

Connect with Theklis

Areas of expertise

  • Web application penetration testing
  • API security
  • Infrastructure security

Writing focus

Theklis writes about application security, penetration testing techniques, and industry challenges. His focus is on sharing practical insights and raising awareness of common security issues to help teams improve their security posture.

Theklis' work

  1. ToolShell Zero-Day lets attackers run code on SharePoint servers
  2. Sudo “chwoot” 1.9.17 - Local Privilege Escalation

    July 16, 2025

    Sudo “chwoot” 1.9.17 – Local Privilege Escalation

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