Senior Penetration Tester — Cloud, Web & Infra Security

Instil; Greater London; On-site; GBP 70,000 - 100,000; Full time

Benefits offered by this job

Performance bonus

Flexible working

Private healthcare

Life assurance

35 days holiday

Learning & certifications

Volunteer & community

Job summary

Instil is seeking a Senior Penetration Tester with CHECK to join our growing team in the UK. You will lead hands-on penetration testing across infrastructure, cloud, web, and mobile applications for a diverse client base, ment oring juniors and shaping our testing methodologies.

The role emphasizes identifying security weaknesses and delivering high-quality engagements, with opportunities to influence internal processes and contribute to challenging projects in a supportive environment.

Qualifications

• Must hold CHECK Team Member (CTM) status and current UK security clearance.
• Minimum 2+ years in penetration testing across infrastructure, web, and mobile contexts.
• Proven ability to perform web application and network pentesting using industry-standard methodologies.
• Solid OS knowledge: Linux, Windows, Active Directory; experience with cloud environments and cloud security reviews.
• Proficient with testing tools Burp Suite Pro, Nmap, Nessus, and Kali Linux; scripting in Python/Shell.

Responsibilities

• Deliver high-quality penetration testing engagements across diverse client base.
• Identify, remediate security weaknesses, and contribute to methodology development.
• Mentor junior testers and support team growth.

Skills

CTM status

UK security clearance

2+ years pentest

Web & network pentest

OS knowledge (Linux/Windows/AD)

Cloud security reviews

BurpSuite Pro/Nessus/Nmap/Kali

Scripting (Python/Shell)

Tools

BurpSuite Pro

Nmap

Nessus

Kali Linux

Job description

Instil is seeking a Senior Penetration Tester with CHECK to join our growing team in the UK. You will lead hands-on penetration testing across infrastructure, cloud, web, and mobile applications for a diverse client base, ment oring juniors and shaping our testing methodologies.

The role emphasizes identifying security weaknesses and delivering high-quality engagements, with opportunities to influence internal processes and contribute to challenging projects in a supportive environment.