Senior Security Engineer – Contract

Flagstone

Senior Security Engineer securing Flagstone’s online savings platform across Azure, Sentinel, and Defender. Improving detection, incident response, vulnerability remediation, and security automation.

Posted 9/8/2026contractLondon • 🇬🇧 United KingdomSeniorWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in cloud security, incident response, and security tooling, with a strong focus on Microsoft Sentinel and Defender for Cloud. Proficient in vulnerability remediation, data-loss prevention, and threat modeling within a fintech or financial services context.

Highest-signal resume keywords

Microsoft SentinelDefender for CloudInfrastructure-as-CodeVulnerability RemediationSC-200 Certification

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Cloud SecurityDetection ToolingIncident ResponseKQL ProficiencyTerraformBicepData-Loss PreventionThreat ModelingAI Workload SecuritySecurity Risk Communication

Soft Skills

Independent WorkClear Communication

Tools & Technologies

Defender XDRAzure NetworkingSIEMSplunkChronicleQRadar

Certifications & Qualifications

SC-200

Industry Keywords

FintechFinancial ServicesSecurity EngineeringAI SecurityIncident Triage

Tech Stack

Tools & technologies

AzureCloudSplunkTerraform

About the role

Key responsibilities & impact

Own and operate alerting and monitoring capability through a transition period
Maintain and improve Microsoft Sentinel, including detection rules, data connectors, and alert-noise reduction
Operate and optimise Defender XDR and Defender for Cloud, including policy management and posture recommendations
Maintain and extend automated security checks in delivery pipelines
Drive vulnerability remediation with engineering squads
Support data-loss-prevention controls
Support safeguards for business access to and use of AI, including AI workload security and data-exposure protection
Investigate suspicious activity in Sentinel and Defender through triage, escalation, or containment
Support incident response, including containment, evidence gathering, and post-incident review
Contribute to detection-as-code and infrastructure-as-code for security tooling
Coordinate penetration tests, including scope, logistics, findings review, and remediation prioritisation

Requirements

What you’ll need

Senior security engineering experience across cloud security, detection tooling, and incident response
Hands-on SIEM experience, ideally Microsoft Sentinel; Splunk, Chronicle, or QRadar considered
Practical Azure security experience across Defender for Cloud, Entra ID, Azure networking, and cloud security posture management
Infrastructure-as-code experience using Terraform or Bicep in a security engineering context
Experience driving vulnerability remediation cycles with engineering squads
Familiarity with data-loss-prevention controls
Familiarity with AI security considerations, including securing AI workloads and data exposure risks, and/or AI tooling for security engineering
Ability to contribute to threat modelling and communicate security risk clearly to engineering and product audiences
SC-200 certification
KQL proficiency for detection rule authoring and threat hunting
Experience in a similar fintech or financial services environment
Ability to work independently and make an immediate impact in a contract role
Legal right to work in the UK

Benefits

Comp & perks

Collaborative, diverse, and inclusive culture
Close support and room to develop
Professional growth opportunities
Meaningful, visible work and impact
Competitive compensation implied by company culture (no specific amount stated)