Continuous Security Penetration Tester

Claranet Limited; England; On-site; GBP 45,000 - 70,000; Full time

Job summary

Claranet Limited is seeking a CST Penetration Tester to join our Continuous Security Testing team. You will identify, understand and remediate vulnerabilities across customer external attack surfaces, using automated scanning alongside hands-on manual testing to validate findings and assess real-world impact.

You will work directly with customers to communicate risks and remediation, while contributing to tooling, methodologies, and security testing capabilities.

Qualifications

• Hands-on experience identifying, validating and exploiting security vulnerabilities.
• Ability to provide practical remediation advice with clear impact.
• Strong written and verbal communication of complex findings to technical and non-technical audiences.

Responsibilities

• Deliver continuous security testing across customer environments, combining automated scanning with in-depth manual assessment.
• Monitor customers' external attack surfaces for changes, emerging vulnerabilities and new targets.
• Manually identify, verify and exploit vulnerabilities to establish their genuine impact.
• Validate automated scanner findings and investigate false positives.
• Produce clear proof‑of‑concepts, reproduction steps and remediation recommendations.
• Communicate technical findings clearly to customers through vulnerability notifications and reports.
• Onboard customers into the Continuous Security Testing service and configure ongoing scanning.
• Research vulnerabilities and tooling to improve testing capabilities.
• Develop internal security testing tools and contribute to improvements.
• Contribute to security advisories and whitepapers.

Skills

Penetration testing

Vulnerability assessment

Technical report writing

Customer communication

Scripting (Python)

Burp Suite Professional

SQLMap

Tools

Burp Suite Professional

SQLMap

Job description

Claranet Limited is seeking a CST Penetration Tester to join our Continuous Security Testing team. You will identify, understand and remediate vulnerabilities across customer external attack surfaces, using automated scanning alongside hands-on manual testing to validate findings and assess real-world impact.

You will work directly with customers to communicate risks and remediation, while contributing to tooling, methodologies, and security testing capabilities.