Senior Offensive Security Engineer - Milan: Pentests

Klarna; Milano; On-site; EUR 73,000 - 93,000; Full time

Job summary

Klarna is seeking a seasoned penetration tester to drive security across production systems and third-party integrations in Milan. You will conduct white-box and black-box tests, triage bug-bounty findings, and analyze code with Java and Node.js to locate vulnerabilities.

You'll build tooling in Python, document clear remediation steps, and mentor teams while evolving Klarna's security program in a dynamic, AWS-based microservices environment.

Qualifications

• 5+ years of penetration testing on production systems.
• Ability to read Java and Node.js code to identify vulnerabilities.
• Experience in AWS and microservice architectures.
• Proficient in Python for tooling.
• Clear, remediation-focused reporting.
• Active security certifications such as OSCP/OSWE/CREST/GIAC are a plus.

Responsibilities

• Run white-box and black-box penetration tests against internal and public systems.
• Triage, investigate, and correlate Bug Bounty submissions and pentest findings.
• Perform variant analysis and trace similar bugs across codebase and infra.
• Assess security of third-party solutions and integrations.
• Build tooling for reconnaissance, automation, and metrics collection.
• Provide guidance to developers, security teams, and SOC during investigations.
• Deliver demos, workshops, and training to spread best practices across Klarna.
• Contribute to maturing Klarna's security program overall.

Skills

Penetration testing

Security assessments

Code reading

AWS

Python scripting

Java

Node.js

Tools

AWS

Java

Node.js

Python

Job description

Klarna is seeking a seasoned penetration tester to drive security across production systems and third-party integrations in Milan. You will conduct white-box and black-box tests, triage bug-bounty findings, and analyze code with Java and Node.js to locate vulnerabilities.

You'll build tooling in Python, document clear remediation steps, and mentor teams while evolving Klarna's security program in a dynamic, AWS-based microservices environment.