Gergely Hajdu

Senior IT → Security (Cybersecurity Analyst)
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Introduction

Profile photo

Gergely Hajdu

Location: Budapest
Occupation: Computer Science Engineer

About Me

I have over 15 years of professional experience in IT operations and data warehouse development, where I gained deep insight into and supported the operation of complex systems within large enterprise environments. I have always prioritized uninterrupted service and robust security, and in recent years I have increasingly oriented my career toward cybersecurity.

To support this transition, I have pursued targeted training to expand and develop my expertise, ensuring I remain up-to-date with practical skills in this fast-evolving field. I am particularly passionate about incident response, threat analysis, and continuously improving the state of system security - areas where I can use my strong analytical mindset and problem-solving abilities.

As an open and eager learner, I believe in contributing to the success of my team not only through technical expertise but also with a collaborative, reliable attitude. I’m convinced that continuous growth, responsible thinking, and meticulous attention to detail are indispensable in cybersecurity, and I strive to create value in every task I undertake.
I would be delighted to join a team where I can further develop my skills, gain new experience, and help drive the organization’s security objectives forward.

What Motivates Me?

I am driven primarily by opportunities for professional growth - such as specialized courses, challenging projects, and hands-on training - as well as a positive work environment and both financial and ethical recognition. It’s crucial for me to work on assignments that deliver tangible value and allow me to fully leverage my expertise.

Professional Interests

From the outset, I’ve been fascinated by emerging technologies. I have always been open to new developments, striving to stay up-to-date with industry innovations. My career has spanned web development, database management, and operations, where I also handled help-desk style user support. In recent years, I’ve shifted my focus to cybersecurity to take an active role in defending systems.

I believe the breadth of my technical background provides a solid foundation for effectively tackling cybersecurity challenges.

Workplaces

  • 2021– : Oracle data warehouse developer
    National Tax and Customs Administration of Hungary, Budapest
    Data warehouse developers, often referred to as data engineers, are responsible for the overall development and maintenance of the data warehouse.
    • Main Responsibilities
      My responsibilities include automation of data services, maintenance of processes, preparation of annual and occasional modifications and handling tickets.
      • Tax Declaration System
        The Tax Declaration System gives comprehensive overview of the changes in the number of submitted tax declarations over the year. The resulting statistics, assessments and reports are widely used by the upper management. The system, being a source of data, plays an important role for planning as well. Furthermore, it provides useful information for all the personnel of the authority to fulfill their daily tasks.
      • Student loan
        The assessment of the income, earned in the current tax year, of loan applicants with a repayment obligation towards Diákhitel Központ Ltd.
      • Facilitation of data services for KSH
        Providing data for KSH on a monthly basis that plays an important role in generating reports.
      • VAT
        Compiling reports and providing data services regarding one of Hungary’s most important source of revenue, the Value Added Tax according to orders.
    • Main tasks
      • design, development, testing, technical coordination and documentation of existing and new data processing processes
      • data provision and reporting
      • participation in the implementation of new systems and projects
    • Other tasks
      • reconciling and specifying business needs
      • implementing business intelligence and analytics
      • design, development and optimisation of the data warehouse
      • participation in the full data warehouse development lifecycle
      • documentation of processes
      • optimising database performance
      • maintaining constant contact with the business, system administrators and IT system operators
  • 2008–2021: Systems Administrator / Systems Operator
    National Tax and Customs Administration of Hungary, Budapest
    Supporting more than 1,000 users, maintaining the hardware and software they use, in collaboration with colleagues and relevant departments, at several different sites and branch offices.
    • General system administrator tasks
      • auditing installed software
      • reviewing system logs, virus scan logs, and other relevant logs
      • checking the proper operation of the devices
      • troubleshooting reported issues by users by phone, remote login, or on-site assistance
      • client-side support in the context of regular on-site fieldwork
      • checking cables
    • Software administrator tasks
      • software installation and configuration (general and company-specific software)
      • providing data backups and ensuring data storage security
      • downloading updates
      • correcting errors detected during the general inspection
      • taking preventive steps
      • correction of errors reported through notifications
      • monitoring the needs of colleagues
      • compiling proposals for the use of existing software, for the acquisition of new software
      • continuous review of security settings and their correction if necessary
      • virus protection, spyware protection
    • Hardware tasks
      • warranty repair of hardware defects detected during the general inspection
      • taking preventive steps
      • making suggestions for buying new devices
      • commissioning, installation and testing of purchased devices
      • preservation of operability and condition, external and internal dedusting, cleaning
      • handling warranty matters for devices within my competence
      • network tasks
      • network construction and operation
      • installation and operation of servers
      • installation and operation of workstations and other units in the network
    • Other tasks that are not closely related to the job, but that facilitate the operation of the organisation

Studies

Higher Education and Vocational Trainings

  • 2025–2026: Information Security System Administrator
    Ruander Oktatóközpont, Budapest
    National Qualification Registry 06125001
    [in progress]
  • 2011–2015: BSc in Computer Science Engineering, Specialisation in Software Development
    Dennis Gabor College, Budapest
    Bachelor’s degree diploma
  • 2005–2007: Multimedia Developer
    Adu Csepeli Vállalkozói Szakközép- és Szakiskola, Budapest
    National Qualification Registry 54840901

Featured Trainings and Certifications

  • 2025: Cybersecurity for Everyone
    Coursera Online Courses
    19 hours, 6 modules, online courses
    [in progress]
    • Defining Cyber, Security, and Cybersecurity Policy
      3 hours, online course
    • Evolution of the Internet
      1 hour, online course
    • Global Telecommunications Architecture and Governance
      3 hours, online course
    • Threat Actors and Their Motivations
      4 hours, online course
    • The Hacking Process
      3 hours, online course
    • End Effects - Direct and Indirect Consequences
      5 hours, online course

Further Trainings and Courses

2025

2024

2023

  • Using Oracle BI EE (Oracle BI Answers)
    in-house training, Budapest
    3-day course, 3x8 hours
  • Java SE basics (JAVA-BSC)
    Training360
    5-day mentored, online course, 5x8 hours
  • Agile PM 101 - Learn the Truth About Agile versus Waterfall
    Udemy Online Courses
    1 hour, online course
  • Augmented Data Visualization with Machine Learning
    Udemy Online Courses
    3.5 hours, online course
  • Modern Data Visualization with Oracle Analytics Cloud
    Udemy Online Courses
    4 hours, online course
  • The Complete Oracle APEX Fundamentals Course (2023)
    Udemy Online Courses
    7 hours, online course
  • Oracle Analytic Functions In-Depth & Advanced Oracle SQL
    Udemy Online Courses
    9.5 hours, online course
  • The Complete Oracle SQL Bootcamp
    Udemy Online Courses
    38.5 hours, online course

2022

2021

2013

2009

  • Administrative exam
    Budapest

2006

  • European Computer Driving Licence
    Budapest

Soft Skills Courses

2025

  • Assertive Communication
    Gerilla Mentorklub
    ??? hours, online course
    [planned]
  • LinkedIn in job searching, changing workplaces, and career transitions
    Gerilla Mentorklub
    4 hours, online course

References

Language proficiency and other skills

Language proficiency

English: Hungarian
  • Native

Other skills

  • Category B Driving Licence

Security Clearances

  • Type C National Security Clearance

Contact

Email address:

LinkedIn: gergely-hajdu-egyprogramozohu