Management TeamManagement Team

Stefan Strobel

CEO and Founder

Stefan Strobel, born in 1970, studied Medical Informatics at Heidelberg University and Intelligence Artificielle at LIA of the University of Savoie in Chambery, France.

Before and during his studies, he had already worked freelance for several IT companies. In 1995, he was one of the founders of Centaur Communication GmbH in Heilbronn, which was sold to the UK company Integralis in 1998, then became Articon-Integralis AG and later NTT Com Security.

At Centaur Communication GmbH, Stefan Strobel was responsible for successfully reorganizing the company to focus solely on IT security. He was the Head of Technology at IntegralisCentaur GmbH, and he designed and implemented some of the first and largest firewall environments used by multinational companies.

When the company was sold, he became Technical Development Director at IntegralisCentaur GmbH, and he was responsible for the selection and evaluation of new technologies and trends at Articon-Integralis AG.

Early in 2002, Stefan Strobel founded cirosec GmbH with some of his former colleagues, and he has been the company’s CEO ever since.

In addition to his regular work, he gives lectures at conferences on current IT security topics, trends, new technologies and security strategies, and he is responsible for the program of the IT-Defense Security Conference. Moreover, he has worked as a lecturer on IT security at different universities.

Stefan Strobel has more than 20 years of experience in consulting major companies with very high security requirements and in developing concepts and policies.

Moreover, he is the author of several technical books, which have been published in different languages, and he frequently publishes articles on IT security in specialist magazines.



Peter Lips


Peter Lips has many years experience managing companies in the IT security field. He provided support for the commercial aspects of Centaur Communication GmbH's reorganization into a company focusing solely on IT security. After the company's sale to Integralis Ltd., he first was the Business Director and later Managing Director of IntegralisCentaur GmbH. After the successful merger of Articon AG and Integralis Ltd., Peter Lips was responsible for operations in German-speaking countries as the Managing Director of Integralis GmbH.

He has been with cirosec GmbH since February 2004, where he is responsible for all commercial aspects.



Steffen Gundel

Partner and Co-Founder

Steffen Gundel studied Medical Informatics at Heilbronn University of Applied Sciences, Heidelberg University and Northumbria University in Newcastle (England). He has worked as an IT security consultant since 1999, and he has developed complex security solutions for large international corporations. He is one of the authors of the book “Firewalls im Unternehmenseinsatz” (literally translated: Firewalls used in companies) published by dpunkt-verlag.

Steffen Gundel has been working at cirosec since April 2002, where his focus is on conceptual IT security and risk analysis. He develops security guidelines and advises our customers regarding the introduction and further development of information security management systems (ISMS) according to ISO/IEC 27001 and “BSI baseline protection" (IT-Grundschutz), on the selection and introduction of tools for security management as well as on innovative and new IT security topics.

In his role as a managing consultant, he has, since 2009, also been responsible for the operational planning of cirosec consultants and for the related overall project management. 

Moreover, he gives talks at various conferences on a regular basis, and he writes articles on current security topics for professional journals.



Marco Lorenz

Partner and Co-Founder

Marco Lorenz completed his studies in Applied Computer Science at Fulda University of Applied Sciences in 1999 with the thesis "Analysis of Weak Points and Optimization of Network Security at the Karlsruhe Research Center by Means of Firewalls with the Case Example Firewall Toolkit“. He continued specializing in the IT security field by working as a consultant for an IT security solutions provider.

Marco Lorenz has been working at cirosec GmbH since April 2002. His focus is on enterprise scanning, vulnerability management, risk management, mobile security, secure data exchange, traceability of administrative access as well as on the conception, development and implementation of security guidelines. 

He is one of the instructors of the cirosec trainings “Forensics Extreme”, “Hacking Extreme Web Applications”, ”Hacking Extreme” and “Hacking Extreme Buffer Overflows” and he has played a vital role in developing these trainings. Moreover, he is a regular speaker at conferences on various topics.



Stefan Middendorf

Partner and Co-Founder 

Stefan Middendorf studied at Heidelberg University (Medical Informatics) and at the Swiss Federal Institute of Technology Zurich. In 1999, he graduated with a thesis on XML and Java.

Having completed his studies, he first worked as an IT security consultant. Later, he joined the Strategic Development team of Articon-Integralis AG and dealt with the evaluation and integration of IT security products with a focus on PKI.

In addition to numerous articles on PKI, Java and XML in various journals, Stefan Middendorf has published books on Linux und Java.

He has been working at cirosec GmbH since April 2002. Today, he is the head in the technical assessment field, and he is responsible for quality assurance. Moreover, the focus of his work is on:

  • architecture and design reviews of complex e-business environments and of applications
  • design guidelines and awareness measures for developers
  • risk analysis

Stefan Middendorf has played a vital role in developing our trainings “Hardening and Secure Configuration” and “Hacking Extreme Web Applications”, and he is a regular instructor of these trainings.



Daniela Strobel

Head of Marketing, Co-Founder and Partner

After having studied economics, Daniela Strobel was the Head of Marketing & Tourism at a city marketing LLC. She then was the Marketing Communication Manager at an IT security company responsible for the marketing in Germany.

She has been with cirosec GmbH since April 2002, where she is responsible for marketing, events and press.