Hi, I’m Krzysztof Greś (h4mr3r). I’m a Red Team Specialist and a malware developer, passionate about building advanced offensive security tools and simulating sophisticated adversary attacks.
What I Do
I work across the offensive security spectrum with expertise in:
- Red Teaming — Simulating advanced persistent threats, Active Directory & Azure exploitation, and physical/logical network breaches.
- Penetration Testing — Comprehensive internal and external infrastructure assessments to identify and chain critical vulnerabilities.
- Malware Development — Crafting evasive payloads, custom Command and Control (C2) frameworks, and low-level system subversion techniques.
Current Projects
Right now I’m focused on:
- Axiom — professional security reporting toolkit
- SIPHON — social-engineering operations toolkit
Experience
Netia S.A
Poland
Oct 2025 - PRESENT
- Senior Cyber Security Consultant Oct 2025 - PRESENT
Leading advanced adversary simulations and enhancing the organization's defensive posture through targeted red team operations and custom malware development
KPMG Poland
Poland
Jul 2021 – Oct 2025
- Senior Cyber Security Consultant Oct 2024 – Oct 2025
- Cyber Security Consultant Apr 2023 – Oct 2024
- Cyber Security Junior Consultant Jan 2022 – Apr 2023
- Cyber Security Intern Jul 2021 – Jan 2022
Progressed from security internship to senior consulting responsibilities across enterprise penetration testing, red team engagements, vulnerability assessments, and stakeholder-facing security reporting.
Certifications
| Issuer | Certification Name |
|---|---|
| Altered Security | Certified Red Team Professional (CRTP) |
| HackTheBox | Certified Penetration Testing Specialist (CPTS) |
| Zero-Point Security | Certified Red Team Operator (CRTO) |
| Zero-Point Security | Certified Red Team Lead (CRTL) |
| Cyberwarfare Labs | Azure Red Team Specialist (AZRTS) |
| Cyberwarfare Labs | Active Directory Red Team Specialist (AD-RTS) |
| Cyberwarfare Labs | Certified Red Team Analyst (CRTA) |
Tech Stack
C++
C
C#
Python
Docker