Senior Penetration Tester (CHECK) – Cloud & Web Security

Instil; Belfast City District; On-site; GBP 75,000 - 110,000; Full time

Benefits offered by this job

Discretionary annual bonus

Flexible working hours

Private healthcare

Life assurance

35 days holiday

Professional development

Volunteer opportunities

Job summary

Instil is seeking a Senior Penetration Tester with CHECK to join our growing team in Belfast. You will lead hands-on engagements across infrastructure, cloud, web, and mobile applications for diverse clients, delivering high-quality findings and remediation guidance.

This role is hands-on, with mentoring of junior testers, contributing to our methodologies, and helping clients strengthen security postures. If you're passionate about offensive security and ready for varied, challenging projects,

Qualifications

• Must hold CHECK Team Member (CTM) status.
• Current UK Security Clearance.
• At least 2+ years of penetration testing experience.
• Strong experience in web and network penetration testing.
• In-depth knowledge of Linux, Windows, and Active Directory.
• Familiarity with cloud environments and ability to perform cloud security reviews.
• Proficiency with BurpSuite Pro, Nmap, Nessus, and Kali Linux.
• Knowledge of scripting languages such as Python and Shell.

Responsibilities

• Deliver high-quality penetration testing engagements across infrastructure, cloud, web and mobile applications for diverse clients.
• Identify, remediate security weaknesses, and help develop our testing methodologies.
• Mentor junior testers and share knowledge to grow the team’s offensive security capabilities.
• Collaborate with clients to translate findings into practical remediation plans.

Skills

CTM status

UK security clearance

2+ years testing

Web & network pentesting

Linux / Windows / AD

Cloud security

BurpSuite Pro / Nmap / Nessus / Kali

Python / Shell scripting

Tools

BurpSuite Pro

Nmap

Nessus

Kali Linux

Job description

Instil is seeking a Senior Penetration Tester with CHECK to join our growing team in Belfast. You will lead hands-on engagements across infrastructure, cloud, web, and mobile applications for diverse clients, delivering high-quality findings and remediation guidance.

This role is hands-on, with mentoring of junior testers, contributing to our methodologies, and helping clients strengthen security postures. If you're passionate about offensive security and ready for varied, challenging projects,