Senior Infrastructure Security Engineer

Senior Infrastructure Security Engineer

London – Industry leading compensation – Hybrid

A high-performance trading firm is expanding the team responsible for the resilience and protection of its internal technology estate. This is a hands-on engineering role for someone who understands how Windows behaves beneath the surface and can turn that knowledge into practical security improvements.

You will work across infrastructure, identity and endpoint security, building solutions rather than simply operating products. The environment is technically demanding, highly automated and designed around reliability, so the focus is on controls that are measurable, maintainable and effective at scale.

What you will do

• Engineer safeguards for Windows endpoints, remote-access platforms and the wider corporate estate.
• Use PowerShell, Python and vendor APIs to remove repetitive work and make security processes consistent.
• Improve prevention and detection through application control, host firewalls, audit policy, telemetry, encryption, Microsoft Defender and exploit protection.
• Drive vulnerability remediation by weighing technical severity against genuine exposure and operational impact.
• Strengthen access and identity controls across Active Directory, Entra ID, Kerberos, privileged accounts and certificate infrastructure.
• Evaluate emerging attack techniques, test their relevance and translate the findings into engineering changes.
• Work closely with platform and software teams so that new protections fit the way systems are built and operated.

Skills needed

• You can explain Windows authentication, logon behaviour, access tokens, privileges, UAC and Group Policy in practical engineering terms.
• You have delivered endpoint controls involving EDR, anti-malware, allowlisting, firewalls, disk encryption, vulnerability tooling or patch management.
• You understand the trust models behind TLS, OIDC, PKI, X.509 certificates and least-privilege design.
• You can distinguish a theoretical weakness from a credible route to compromise and set remediation priorities accordingly.
• You write reliable PowerShell for production use. Python, other scripting languages and security product integrations are useful additions.
• You communicate clearly, make balanced risk decisions and can move technical work forward without losing sight of operational constraints.

Other usefull skill

• Experience securing Linux or another operating system alongside Windows.
• A background in an engineering-led organisation where security controls are reviewed, tested and evolved like production software.

This role offers the chance to investigate difficult security problems, work closely with experienced engineers and shape protections for an environment where performance and reliability matter. It will appeal to someone who enjoys understanding systems in depth and prefers building durable solutions to applying standard fixes.

All applications are handled in strict confidence.