Senior Security Engineer (OT - Sec Ops)

Join DayOne – Shaping the Future of Data Infrastructure DayOne is a global leader in the development and operation of high-performance data centers. As one of the fastest-growing companies in the industry, we’ve built a robust presence across Asia and Europe — and we’re just getting started. As we expand into new international markets, we’re looking for talented, driven individuals to join us on this exciting journey. This is more than a job — it’s an opportunity to be a key contributor to our dynamic team and help shape the future of global data infrastructure. If you're passionate about innovation, technology, and growth, we invite you to be part of DayOne’s next chapter. 1. Security Monitoring, Analysis, and SOC Support • Monitor, review, and analyse security events, alerts, logs, and anomalous activities across IT and OT environments, including critical facility-supporting systems where visibility is available. • Support SOC activities such as alert triage, case enrichment, initial investigation, false positive reduction, and escalation in accordance with defined procedures and severity criteria. • Assist in developing, tuning, validating, and documenting detection use cases and alerting requirements for converged IT-OT environments and operationally critical assets. • Correlate information from SIEM, endpoint, network, identity, vulnerability, and infrastructure sources to identify suspicious activity, control weaknesses, or potential security incidents. 2. OT Security and Critical Environment Protection • Support the protection of OT and facility-supporting technologies such as BMS, EMS, DCIM, environmental monitoring, and other operational or industrial control components. • Assist in reviewing segmentation, remote access controls, jump host arrangements, privileged access, logging coverage, backup protection, and hardening requirements for OT-related systems. • Help validate that OT connectivity, vendor access, and system integrations are controlled, documented, and aligned with internal security requirements and operational constraints. • Contribute to improving OT security baselines, asset visibility, and operational security practices using guidance from IEC 62443 and other relevant standards where appropriate. 3. Incident Response and Security Investigation • Support investigation and coordination activities for cybersecurity incidents, suspicious events, control failures, malware detections, unauthorised access attempts, or operational anomalies affecting IT or OT environments. • Assist with evidence gathering, timeline reconstruction, root cause analysis, lessons learned, and remediation tracking for security events and incidents. • Maintain or contribute to incident response procedures, escalation matrices, use case playbooks, and recovery or contingency documentation relevant to critical operational systems. • Work with relevant teams during incidents, exercises, or post-incident reviews to ensure security observations are captured and follow-up actions are completed. 4. Technical Security Review and Control Assurance • Support reviews of segmentation, access control, logging, monitoring, patching, vulnerability management, antivirus or EDR coverage, and secure configuration practices across IT-OT environments. • Assist in validating that operational systems and supporting infrastructure are appropriately governed, monitored, and protected against common cyber threats and misconfigurations. • Coordinate with infrastructure, facilities, engineering, and system owners to follow up on identified weaknesses, overdue remediation items, or control gaps. • Support technical assessments, health checks, or control validation exercises for new or existing deployments affecting critical environments. 5. Risk, Compliance, and Governance Support • Assist with IT and OT security risk assessments for systems, projects, sites, third-party integrations, and technology changes. • Maintain and update risk registers, action trackers, findings logs, and records of identified control gaps and mitigation plans. • Support compliance activities relating to ISO 27001, SOC 2, PCI DSS, NIST CSF, IEC 62443, and other relevant internal or external requirements. • Prepare, organise, and track evidence for audits, customer reviews, internal assessments, and certification activities. 6. Third-Party, Vendor, and Project Security Coordination • Support cybersecurity reviews for vendors, integrators, contractors, and service providers that connect to or manage IT-OT environments. • Assist in tracking remote access controls, onboarding or offboarding requirements, maintenance windows, and security conditions for third-party activities affecting OT or critical systems. • Help review submitted designs, configurations, implementation plans, or change requests against internal security requirements and standards. • Coordinate follow-up actions with project managers, engineers, system owners, SOC personnel, and external parties where required. 7. Documentation, Reporting, and Awareness • Prepare security analysis summaries, governance reports, status updates, dashboards, and management-level outputs for internal forums or leadership review. • Maintain accurate records of incidents, investigations, assessments, reviews, issues, actions, approvals, use cases, and supporting documentation. • Support awareness and training activities relating to cybersecurity, operational discipline, incident reporting, and secure practices in IT-OT environments. • Promote good security hygiene, accountability, and adherence to defined procedures and standards across both technical and operational stakeholders. Skills and Qualifications • Bachelor’s degree in Cybersecurity, Information Security, Information Technology, Computer Science, Engineering, or a related discipline. • Typically 3-5 years of experience in cybersecurity operations, SOC, infrastructure security, OT security, or a related…