Security Engineer

Addition; Farnborough; Hybrid; GBP 90,000 - 120,000; Full time

Benefits offered by this job

Private medical

10% pension contribution

Bonus

Wider benefits

Job summary

Addition is a specialist technology business delivering secure, mission-critical solutions across Defence and National Security. The role focuses on designing and maintaining secure identity, credential management, PKI, AD CS and PAM implementations in highly secure environments.

You’ll work with CyberArk or comparable PAM platforms, RBAC configuration, and secure migrations, with hybrid working in Farnborough and a strong emphasis on security assurance and compliant delivery.

Qualifications

• Design, implement, integrate and maintain secure identity, privileged access and cryptographic solutions.
• Manage credential lifecycles, including passwords, SSH keys and API keys, with automated rotation.
• Carry out network and Active Directory discovery to identify privileged accounts and system dependencies.
• Support and troubleshoot Microsoft PKI and Active Directory Certificate Services, including CA renewals.
• Administer and support enterprise HSM infrastructure and key management.

Responsibilities

• Design and implement secure PKI/IAM tooling and PAM integrations.
• Manage credential lifecycles including SSH keys and API keys.
• Monitor platform health and security controls, address vulnerabilities.
• Configure RBAC structures and ensure privileged access is auditable.
• Troubleshoot AD CS, OCSP, and certificate services across environments.

Skills

IAM/IDAM

PAM (CyberArk)

PKI/AD CS

HSM (Thales Luna)

MITRE ATT&CK

CI/CD security

Threat modeling

Tools

Thales Luna HSM

Active Directory

PKI management tools

Job description

Join a specialist technology business delivering secure, mission-critical solutions across Defence and National Security. You’ll work on complex security challenges where your technical expertise directly supports systems that protect what matters.

Role Overview

• Package: Competitive salary + bonus, private medical, 10% employer pension contribution and wider benefits
• Industry: Defence & National Security

What You’ll Be Doing

• Design, implement, integrate and maintain secure identity, privileged access and cryptographic solutions.
• Manage credential lifecycles, including passwords, SSH keys and API keys, with a focus on reliable automated rotation.
• Carry out network and Active Directory discovery to identify privileged accounts, service accounts and system dependencies.
• Support and troubleshoot Microsoft PKI and Active Directory Certificate Services, including Certificate Authorities and certificate renewals.
• Administer and support enterprise HSM infrastructure, including Thales Luna, key management and secure migrations.
• Maintain OCSP and certificate validation services to support trusted authentication and secure communications.
• Integrate PKI, IAM/IDAM, PAM, Active Directory and wider security tooling across highly secure environments.
• Work with CyberArk or comparable PAM platforms to manage privileged identities, credentials and access controls.
• Configure RBAC structures and permissions, ensuring privileged access remains controlled, auditable and appropriate.
• Monitor platform health, security controls and performance, proactively addressing vulnerabilities and operational issues.
• Manage security patching, platform upgrades, licensing and technical maintenance.
• Configure and verify backup processes to support agreed recovery objectives.
• Investigate authentication, certificate, PKI, HSM, firewall, load balancer and connectivity issues across complex environments.
• Review audit logs, privileged sessions and security alerts to identify unusual activity and support compliance.
• Monitor active privileged sessions and investigate potential weaknesses or suspicious behaviour.
• Work closely with engineers, architects and delivery teams on low-level technical designs and secure implementations.
• Contribute to security assurance and compliance activities within Defence and National Security environments.

Main Skills Needed

• Strong experience deploying and managing enterprise security technologies, such as vulnerability management and EDR solutions.
• Practical experience with IAM/IDAM, Directory Services, identity providers and Privileged Access Management.
• Hands-on knowledge of Microsoft PKI / AD CS and enterprise certificate management.
• Experience with HSM technologies, ideally Thales Luna, alongside knowledge of cryptographic key management.
• Understanding of FIPS 140-3, OCSP and Certificate Authority infrastructure.
• Experience integrating PKI, IAM and PAM with wider secure infrastructure.
• CyberArk or comparable PAM experience.
• Good understanding of security principles and threat frameworks such as MITRE ATT&CK.
• Comfortable producing clear technical documentation and working at low-level design level.
• Knowledge of Agile, DevSecOps and CI/CD within secure or regulated environments.
• Understanding of MOD security assurance and policies.
• Strong troubleshooting, analytical and problem-solving skills.
• A proactive mindset, with the curiosity and ownership to improve how secure technology is delivered.

What’s in It for You

• Hybrid working in Farnborough.
• 25 days annual leave plus bank holidays.
• Free private medical cover.
• Life assurance.
• Professional development and training support.
• Secure on-site parking.
• Open, collaborative breakout spaces.
• The chance to work on technically challenging projects with genuine Defence and National Security impact.
• A culture built around agility, security, innovation, quality, collaboration and inclusivity.

Please note: Due to the secure nature of the role, you’ll need to hold or be eligible to obtain the required level of UK Security Clearance.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.