Linux System Administration and Security Consultant

Consultant Linux System Administration & Security (F/H)

At SII, the diversity of sectors, architectures, and technical challenges nourishes your expertise and accelerates your development. For over 40 years, we have been supporting our clients in the Aeronautics & Defense, Banking, Energy, Transport, and Telecom sectors. Thanks to our key references and our positioning with major players such as Thales, Airbus, SNCF, BNP Paribas, Bouygues Télécom, or Enedis, our employees work on high-value-added projects, often in critical, large-scale, or highly secure environments.

Why Join Our Cybersecurity Practice?

Facing the growing challenges of infrastructure availability, performance, and security, our practice supports major industrial, banking, and public sector players in the design, evolution, and securing of their information systems. With over 80 experts, we cover the entire spectrum of cybersecurity, from offensive evaluation (penetration testing, red teaming) to operational defense (monitoring, detection, incident response, securing cloud environments), and governance, risk, and compliance (GRC) activities (audits, risk analyses, awareness, regulatory compliance (ISO 27001, DORA, NIS2...), and strategic consulting).

Your Missions

As a Linux System Administration & Security Consultant, you will be involved in missions of secure administration, hardening, and security maintenance of Linux environments.

Secure Administration & Operation

• Administer Linux environments (RedHat, CentOS, Debian, Ubuntu...).
• Ensure operational and security maintenance (MCO/MCS).
• Manage updates, security patches, and critical fixes.
• Supervise systems and analyze logs.

Hardening & Securing

• Implement hardening policies.
• Configure and maintain security mechanisms (SSH, sudo, PAM, Linux firewall, etc.).
• Participate in remediation actions following audits or vulnerability scans.
• Contribute to securing virtualized or cloud environments.

Automation & Continuous Improvement

• Automate administration tasks via scripts (Bash, Python).
• Contribute to Infrastructure as Code (Ansible, etc.).
• Participate in the continuous improvement of configurations and security standards.

Documentation & Coordination

• Write operational and security procedures.
• Collaborate with network, security, and other teams.
• Participate in incident management teams if necessary.

Your Work Environment

You will join a committed and supportive team, where expertise sharing and collective progress are central. Within our cyber community, you will have access to:

• Certifying training: editor certifications, infrastructure security, CISSP, CCNA/CCNP Security, etc.
• Technical workshops, communities, and internal events to exchange with peers.
• Opportunities for visibility: conferences, school interventions, publications.

At SII, curiosity is encouraged, skill development is supported, and collaboration is at the heart of our practices.

Profile Required

Graduated from an engineering school or equivalent university program, you have at least 3 years of experience in Linux system administration in a secure environment.

Your Strengths

• Solid Linux administration skills.
• Good understanding of system security principles.
• Knowledge of hardening mechanisms and vulnerability management.
• Experience in scripting (Bash, Python).
• Rigor, autonomy, and analytical skills.
• Team spirit and good interpersonal skills.

Beyond technical skills, your rigor and ability to evolve in demanding environments will make the difference.

About SII

The SII group is at the heart of innovation serving large accounts in various engineering sectors. For the 8th consecutive year, SII France has obtained the Great Place To Work® label and ranks 2nd in the Best Workplaces 2025 ranking (category +2500 employees). We are very proud of this because we are the first ESN (IT services company) in this ranking to receive this recognition from our employees! This success reflects our culture based on our desire to offer all our employees a fulfilling work environment for the development of their skills and careers. Joining SII means embarking on a collective adventure: Let's Tech Together! This promise represents our shared ambition: to build a technological future together, in an environment where experimentation and autonomy are encouraged, where innovation is at the heart of our actions, and where each employee finds professional fulfillment and responsibility within an enthusiastic and inclusive collective. As a company with strong human values, we are signatories of the Charter of Diversity, the Charter of LGBT+ Commitment with the Association l'autre Cercle, and we are a Handi-friendly company. Let's Tech Together embodies who we are and what we aspire to be: a dynamic, innovative, and human company. So if these values resonate with you, join us!

Key skills/competency

• Linux System Administration
• Cybersecurity
• System Hardening
• Vulnerability Management
• Bash Scripting
• Python Scripting
• Infrastructure as Code
• Security Audits
• Incident Response
• Cloud Security