Senior/Principal Security Infrastructure Engineer

IO Associates; Bridgwater; Hybrid; GBP 70,000 - 90,000; Full time

Job summary

A leading tech consultancy is looking for a Senior/Principal Security Infrastructure Engineer to provide technical leadership and hands-on expertise in securing enterprise infrastructure. This role focuses on resilience, compliance, and integrity within a complex technology environment, and includes designing secure network architectures, managing MFA solutions, and operating SIEM tools. The position offers flexible work arrangements and opportunities for career development, making it a valuable opportunity for experienced professionals.

Qualifications

• Proven experience in infrastructure or network security within enterprise environments.
• Strong knowledge of Microsoft technologies, such as Windows Server, Active Directory.
• Hands-on experience with MFA, virtualisation, and network security appliances.

Responsibilities

• Design and maintain secure on-premises and cloud network architectures.
• Harden Microsoft Server/Desktop platforms and Group Policies.
• Deploy and manage MFA solutions for enterprise protection.
• Secure virtualisation platforms and implement endpoint security.
• Operate SIEM tools for threat detection and incident response.
• Perform vulnerability assessments and drive remediation.

Skills

Infrastructure or network security experience

Microsoft technologies expertise

Hands-on experience with MFA and virtualisation

Understanding of SIEM operations

Familiarity with security frameworks

Problem-solving skills

Communication skills

DV clearance

Tools

Splunk

Microsoft Sentinel

Qualys

Tenable

Job description

Senior/Principle Security Infrastructure Engineer

Permanent | £70,000 to £90,000 | Bristol (hybrid)

Our client is seeking a Senior/Principle Security Infrastructure Engineer to provide technical leadership and hands‑on expertise in securing enterprise infrastructure and networks. This role focuses on resilience, compliance, and integrity across a complex multi‑technology environment.

Key Responsibilities

• Design, build and maintain secure on‑premises and cloud network and system architectures
• Harden Microsoft Server/Desktop platforms, Active Directory, and Group Policies
• Deploy and manage MFA solutions (YubiKey, RSA) for enterprise identity and access protection
• Secure virtualisation platforms (Hyper‑V, VMware) and implement endpoint security (EDR, anti‑malware, DLP)
• Operate and optimise SIEM tools (Splunk, Microsoft Sentinel) for threat detection and incident response
• Perform vulnerability assessments using Qualys and Tenable, driving remediation and continuous improvement
• Align security controls with ISO 27001, NIST, CIS, and Cyber Essentials, supporting audits and compliance

Skills & Experience

• Proven experience in infrastructure or network security within enterprise environments
• Strong knowledge of Microsoft technologies (Windows Server/Desktop, Active Directory, Group Policy)
• Hands‑on experience with MFA, virtualisation, and network security appliances
• Understanding of SIEM operations, vulnerability management, and endpoint protection
• Familiarity with recognised security frameworks (ISO 27001, NIST, CIS, Cyber Essentials)
• Excellent problem‑solving and communication skills
• DV cleared.

A key opportunity to lead technical security initiatives, embed best‑practice controls, and work on strategic infrastructure projects with flexible working and career development opportunities.