2 months ago
London, United KingdomSenior
Responsibilities
- Run white-box and black-box penetration tests against internal systems and public-facing applications.
- Manage, triage, and investigate bug bounty submissions and external penetration-testing findings.
- Perform variant analysis to identify related vulnerabilities across the codebase and infrastructure.
- Research and assess the security of third-party solutions and integrations.
- Build tooling for reconnaissance, automation, and metrics collection.
- Guide developers, product security teams, and SOC investigations with hands-on offensive-security expertise.
- Deliver demonstrations, workshops, and training on offensive-security practices.
- Assess the security of Klarna’s technology stack and help mature the overall security program.
Requirements
- At least 5 years of experience conducting penetration tests and technical security assessments against production systems.
- Ability to read code and identify vulnerabilities, particularly in Java and Node.js.
- Experience operating in AWS and reviewing microservice architectures for security gaps.
- Ability to write clear findings with concrete remediation steps for developers.
- Ability to script reconnaissance and security tooling in Python.
- Ability to independently advance offensive-security work and initiatives.
- Industry certifications such as OSCP, OSWE, CREST, GIAC, or an AWS security certification are advantageous.
- Active CTF participation, security-community involvement, or public security research such as CVEs, conference talks, or published tooling is advantageous.
Benefits
- The position is based in Klarna’s London office.
- Most teams currently meet in person 2–3 days per week, though this varies by team and may change over time.
About Klarna
Klarna is a privately held fintech that provides buy now, pay later financing, checkout, and a consumer shopping app for e-commerce and retail. It monetizes through merchant fees, interchange, and interest and fees on financing, while offering marketing and customer acquisition tools to merchants. Founded in 2005 and headquartered in Stockholm, it operates across Europe and North America.