Senior Information Security Tester — Penetration Expert

Sainsbury's Limited; City Of London; On-site; GBP 65,000 - 90,000; Full time

Benefits offered by this job

Colleague discount across brands

Holiday allowance

Bonus scheme

Pension plan

Private healthcare

Job summary

Sainsbury's Tech is seeking a Senior Information Security Tester to lead penetration testing across internal and external systems. You will own testing engagements, create detailed, actionable reports, and mentor junior staff while collaborating with multiple teams to improve overall security posture.

Key focus areas include identifying vulnerabilities, providing guidance, and shaping testing processes aligned with industry standards and regulatory requirements.

Qualifications

• Proven experience in web application penetration testing with strong OWASP knowledge.
• Experience conducting infrastructure pen tests on Windows and Linux.
• Ability to write clear, technical reports for diverse audiences.
• Good quality assurance of vulnerability write-ups and reports.

Responsibilities

• Scope penetration testing for internal and external facing systems.
• Perform a wide range of tests and deliver detailed reports with actionable recommendations.
• Provide expert feedback in vulnerability and process forums.
• QA in-house reports and vulnerability database write-ups.
• Improve vulnerability write-ups to raise report quality.
• Assist teams in understanding security vulnerabilities and implications.
• Review external pentests as part of vendor evaluation and provide feedback.
• Mentor team members and fill knowledge gaps as needed.
• Engage in Purple Team activities; Red Team capabilities are a plus.
• Contribute to planning, design, and improvement of security testing processes.

Skills

Web app pentests

OWASP knowledge

Infrastructure pentests

Report writing

Security testing communication

Purple Team experience

Education

Certifications (OSWE/OSCP/GIAC/CREST)

Tools

Reporting platform

Job description

Sainsbury's Tech is seeking a Senior Information Security Tester to lead penetration testing across internal and external systems. You will own testing engagements, create detailed, actionable reports, and mentor junior staff while collaborating with multiple teams to improve overall security posture.

Key focus areas include identifying vulnerabilities, providing guidance, and shaping testing processes aligned with industry standards and regulatory requirements.