Senior Cloud Security Engineer — Immediate Impact (Contract)

Flagstone; Greater London; On-site; GBP 111,000 - 166,000; Full time

Job summary

Flagstone is seeking a senior security engineer for a contract role in the UK. You will own critical detection and response capabilities across cloud security, incident response, and security tooling, with hands-on work on Azure Defender for Cloud, Sentinel, and AI security considerations.

You will write infrastructure-as-code, coordinate pen tests, and partner with engineering to drive rapid remediation. The role rewards practical impact and visible results.

Qualifications

• Hands-on SIEM experience with modern tooling (Microsoft Sentinel preferred).
• Strong Azure security knowledge across Defender for Cloud and Entra ID.
• Experience writing IaC with Terraform or Bicep in security projects.
• Proven ability to drive vulnerability remediation with engineering teams.
• Awareness of data-loss-prevention controls and AI security considerations.

Responsibilities

• Own and operate alerting and monitoring during transitions with steady detection and response.
• Maintain and improve Microsoft Sentinel deployment: rules, connectors, noise reduction.
• Operate Defender XDR and Defender for Cloud; manage policies and posture.
• Extend automated security checks in delivery pipelines (shift-left).
• Lead remediation coordination with engineering squads to reduce Down Time.
• Support data-loss-prevention controls and access safeguards for AI workloads.
• Investigate Sentinel/Defender alerts: triage, escalate, contain as needed.
• Support incident response activities: containment, evidence gathering, post-incident review.
• Contribute to detection-as-code and IaC tooling (Terraform/Bicep).
• Coordinate penetration testing engagements and prioritize findings with teams.

Skills

SIEM

Azure security

Threat modeling

Incident response

KQL proficiency

Terraform/Bicep

Vulnerability remediation

AI security

Fintech experience

Security operations

Tools

Microsoft Sentinel

Azure Defender for Cloud

Entra ID

Terraform

Bicep

Job description

Flagstone is seeking a senior security engineer for a contract role in the UK. You will own critical detection and response capabilities across cloud security, incident response, and security tooling, with hands-on work on Azure Defender for Cloud, Sentinel, and AI security considerations.

You will write infrastructure-as-code, coordinate pen tests, and partner with engineering to drive rapid remediation. The role rewards practical impact and visible results.