Infrastructure Engineer (Security & PKI) Location: Corsham Security Clearance: DV Cleared or Eligible Overview We are looking for an infrastructure engineer to support and maintain secure enterprise infrastructure and Public Key Infrastructure (PKI) services within a highly secure environment. This role combines infrastructure operations, security engineering, and identity management, supporting critical systems across Windows Server, Active Directory, Azure, Intune, and PKI platforms. You will be responsible for incident resolution, service delivery, platform maintenance, and ensuring the ongoing security and availability of key services. Key Responsibilities: Infrastructure Support & Operations Provide 2nd and 3rd line support across infrastructure and security platforms. Manage incidents, service requests, problems, and change activities. Administer Windows Server and Active Directory environments. Support Azure AD administration and Single Sign-On (SSO) integrations. Configure and maintain Microsoft Intune. Monitor Microsoft Defender and respond to security alerts. Perform system maintenance, patching, backups, and health checks. PKI & Identity Management Support Public Key Infrastructure services, including Root, Subordinate, and Issuing Certificate Authorities. Troubleshoot certificate issuance, renewal, revocation, and validation issues. Manage certificate lifecycle activities including renewals, rekeying, and inventory management. Monitor CA services, CRLs, OCSP responders, and associated PKI infrastructure. Assist with maintaining cryptographic inventories and security controls. Security & Compliance Ensure adherence to security policies, standards, and best practices. Support audit and compliance activities. Review security events and operational logs. Maintain accurate technical documentation and operational procedures. Support role-based access controls and secure administration practices. Skills & Experience Essential Experience administering Windows Server and Active Directory environments. Strong understanding of networking fundamentals including DNS, DHCP, and TCP/IP. Experience supporting enterprise infrastructure in secure environments. Knowledge of PKI concepts including Certificate Authorities, CRLs, OCSP, and key management. Experience with Azure, Azure AD, Microsoft Intune, or similar cloud technologies. PowerShell scripting experience for automation and operational tasks. Familiarity with Microsoft MMC, Event Viewer, and monitoring or SIEM tools. Understanding of backup, recovery, and disaster recovery processes. Experience working within ITIL-based service management environments. Knowledge of security frameworks and standards such as NIST and GDPR. Strong troubleshooting, documentation, and communication skills. Desirable CompTIA Security or equivalent security certification. Experience working within highly regulated or government environments. Exposure to enterprise PKI platforms and cryptographic services. What We're Looking For A proactive and analytical problem solver. Strong attention to detail and commitment to security best practices. Ability to work independently and as part of a wider technical team. Comfortable operating within structured and highly secure environments. Excellent communication and stakeholder engagement skills. Salary: Competitive Security Clearance: DV Clearance Required or Willingness to Undergo Clearance Process.