01.10.2025 aktualisiert

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Cyber Security Engineer

Schoenefeld, Deutschland
Weltweit
Bsc(Hons) University of Reading - Computer Science and AI
Schoenefeld, Deutschland
Weltweit
Bsc(Hons) University of Reading - Computer Science and AI

Profilanlagen

Kostopoulos_Freelance_Oct_2025.pdf

Skills

Amazon Web ServicesArchitekturdesignAutomatisierungMicrosoft AzureBusiness To BusinessCloud ComputingCloud-SicherheitInformationssicherheitKryptographieLinuxKryptographische ProtokolleHIPAAInfrastrukturISO / IEC 27001PythonKey ManagementLinux KernelOWASPReverse EngineeringRisikoanalyseSupply Chain ManagementSicherheitsrichtlinienShell-ScriptTechnische LeitungVulnerability ManagementBedrohungsmodelSicherheitsauditsInformationsverwaltung und -managementSicherheitsstrategienSoftware SecuritySicherheitsberatungDSGVOSicherheitsbestimmungenRisikomanagementDevSecOpsGolang
Security Architecture, Security Strategy, Threat Modeling, STRIDE, DREAD, EoP Poker, Risk Management, Risk Analysis, Cloud Security, Infrastructure Security, AWS Security, Azure Security, Hybrid Cloud, Secure Architecture Design, Software Security, Application Security, OWASP Top 10, CWE-25, Cloud-Native Security, Vulnerability Management, Security Governance, Compliance Frameworks, SOC 2, HIPAA, ISO 27001, GDPR, Reverse Engineering, Binary Analysis, ELF, x86_64, ARM64, Binary Ninja, Cryptography, Key Management, Encryption Protocols, Cryptographic Attacks, Security Automation, Python 3, Golang, Shell Scripting, DevSecOps, Compliance Automation, Security Policy Design, Secure Software Supply Chain, Security Audits, Technical Leadership, Stakeholder Communication, Product Security, Internal Security Audits, B2B Security Consulting, Rust, C17, Linux Kernel Internals, Memory Allocators, Linux Namespaces, Linux Capabilities, Syscall Hardening

Erfahrung

Berufserfahrungmehr als 10 Jahre
Freelancer seit2022

Sprachen

DeutschGrundkenntnisseEnglischverhandlungssicherGriechischMuttersprache

Projekthistorie

Staff Security Engineer - Tigerdata Inc (NYC/Berlin)

Tigerdata Inc (Creators of Timescale)

Internet und Informationstechnologie

50-250 Mitarbeiter

  1. Designed, implemented, and communicated annual security strategy roadmaps aligned with tangible business objectives (e.g., market expansion, multiple compliance certifications). Acted as the primary point of contact for external auditors and vendors, representing Product Security, often in tandem with Legal.
  2. Established security-focused SOPs across Engineering, Technical Support, and Professional Services to ensure consistent, risk-aware operations company-wide.
  3. Introduced and applied STRIDE threat modeling to identify and mitigate design-level risks early in the SDLC, significantly reducing downstream remediation costs.
  4. Defined and expanded technical guardrails for cloud and software services; verified security posture through internal audits and continuous assessment.
  5. Designed and deployed SCA, SAST, and DAST security tooling in CI/CD pipelines, proactively identifying and mitigating vulnerabilities before production. Championed widespread use of compiler binary exploitation protections, effectively downgrading or eliminating memory corruption vulnerabilities.
  6. Led successful security initiatives for bolstering implementing cryptographic measures and access controls to protect data at rest and in transit.

Staff Security Engineer

LemmaTree/Temasek

Internet und Informationstechnologie

50-250 Mitarbeiter

1. Vulnerability assessment of Web Applications / APIs, leading to elimination of critical and
high vulnerabilities before 3rd party verification.
2. Introduced threat modelling and architectural review of applications, leading to early
elimination of security defects.
3. Provider of security consultancy services to product teams.

Sr Security Architect

Zalando SE

Internet und Informationstechnologie

>10.000 Mitarbeiter

1. Enabled SCA across all verticals for scanning of Docker containers, leading to greater
security confidence in basic software building blocks.
2. Threat modelling and creation of Risk Register for Machine Learning teams, allowing
usage of GDPR sensitive data for ML training.
3. Security consulting services to various software engineering teams.

Independent DevSecOps Consultant

1. Created AWS Kubernetes observability platform for a major mobility technology and data
analytics company, increasing visibility and reducing MTTR.
2. Performed Kubernetes security review for a Fintech, identifying potentially critical security
defects.
3. Migration of Kubernetes clusters and related Python3 tooling from AWS to Azure for a
leading location intelligence company.

Security Lead

Ambidexter/Deutsche Bank AG

Banken und Finanzdienstleistungen

50-250 Mitarbeiter

1. 6 direct reports (1:1s/goal setting/feedback cycles/mentoring).
2. Software and infrastructure security guidance, increasing security awareness within the
organization.
3. Technical advisory services to C-Level management, allowing alignment across different
engineering verticals.
4. Hiring/scaling up of security team, reducing reliance on expensive outside consultants.

Principal DevSecOps Engineer

OSRAM Innovation Lab
1. Azure Kubernetes (self-hosted) maintenance and extension (IaC using Terraform).
2. Code reviews to ensure that code deployed complied with scalability and security
requirements, increasing confidence of deployed code.
3. Active member of security team in infrastructure/cloud security issues, allowing
maintenance of security posture.

Sr Software Engineer - Service Reliability

Red Hat
1. SLI/SLO definitions.
2. Golang development of OpenShift on Azure.

Sr Reliability Engineer

Zalando SE
1. Design, security study and implementation of business-unit AWS Big Data Warehouse,
reducing reliance to resources outside the business unit.
2. AWS/Kubernetes migration of legacy mission critical systems, leading to reduced incident
count and expanded uptime.
3. Active interviewer for SRE and Python backend positions.

Sr Systems Architect

Core SE
1. Design and implementation of microservices based architecture for FinTech sector.
2. Implementation of On-Prem Kubernetes clusters.
3. Mentoring and coordination of Jr colleagues.

Sr DevOps Engineer

Here/Nokia
1. Development, automation, and supervision of software release pipelines, shortening end-toend
software delivery timelines.
2. Creation, administration, and automation of existing and new cloud-based Linux
infrastructure.
3. Delivered internal presentations and mentored Jr colleagues.

Independent Systems Engineer

Startups
1. Administration of geographically distributed Ubuntu Linux infrastructure.
2. Introduction of centralized logging (Logstash).
3. Administration of existing Linux infrastructure (Nginx, PHP, PostgreSQL).

Linux System Administrator

Neofonie
1. Administration of Linux infrastructure (Apache, Tomcat, MySQL).
2. Deployment of software releases in staging and production environments.
3. Create plugins for existing monitoring tools (Nagios).

Independent Security Consultant

ICS-FORTH, Security Innovation, Obrela Security
Obrela Security - Amsterdam, Athens, Heraclion)
1. Design and implementation of a secure file synchronization application.
2. Application/Network penetration testing for a variety of financial service clients.
3. Design threat modeling and source code security review.

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