Senior Email Security Administrator

Job Description Reporting to the Global Head of Security under Platform Security, the Senior Email Security Administrator leads the Email Security program, owning the design, implementation, and optimization of Mimecast and Proofpoint Tessian Mimecast solutions, and partnering with the IT Messaging team to ensure secure messaging delivery and protection against phishing, malware, data loss, and business email compromise (BEC).

The role requires deep technical expertise, hands-on execution, and collaboration with IT teams. The ideal candidate will have extensive hands-on experience in email security technologies, strong analytical skills, and a proactive approach to problem-solving.

• 
  
• Act as the organization’s de facto Email Security Administrator who owns the design, deployment, and ongoing operations for the organization’s Secure Email Gateways (Mimecast, Proofpoint Tessian).
  
• Design and own the email security architecture across Mimecast, Tessian, and Microsoft 365 and Exchange Online, ensuring robust protection against threats.
  
• Drive and own policy tuning, balancing security with favorable user experience, and work towards reducing false positives in email security systems and end-user alerts.
  
• Serve as the primary point of contact for email and messaging security initiatives, ensuring effective communication and collaboration with Global Cyber Fusion Center Incident Response and IT Messaging/Ops teams and other stakeholders.
  
• Regularly generate security posture and KPIs to senior management to ensure accountability.
  
• Document runbooks and technical SOPs for process alignment and to describe technical specifications for email security infrastructure and related policies.
  
• Assist with investigations and responses for high-severity email threats, including phishing, impersonation, and business email compromise (BEC).
  
• Work with Global Cyber Fusion Centre Security Operations Center (SOC), IT and Compliance teams to align processes and escalation protocol.
  
• Support audits, risk assessments, and security reviews to maintain compliance and enhance security measures.
  
• Evaluate next generation cyber solutions related to Email and DLP.
  
• Provide security advisory and best-practice recommendations that align with the organization’s risk profiles and business objectives.
  

• 
  
• Bachelor’s degree in computer science, Information Security, or related professional experience.
  
• 7+ years of experience in Cybersecurity, with a strong focus on Email and Messaging Security.
  
• Extensive, hands-on experience administering Mimecast, Proofpoint Tessian Secure Email Gateways as an enterprise email security administrator.
  
• Proven experience securing Microsoft 365 and Exchange Online environments with a solid understanding of Entra ID for users and group management.
  
• Experience in Microsoft Purview with Data Loss Prevention (DLP) and user behavior analytics is a big plus.
  
• Strong knowledge of phishing, social engineering, and BEC threats, along with email authentication protocols (SPF, DKIM, DMARC) and encryption standards (TLS).
  
• Familiarity with SIEM/SOAR integrations (e.g., Splunk, Sentinel, QRadar).
  
• Relevant security certifications such as CISSP, Security+ with certifications specific to administering Secure Email Gateways (e.g., Ironport, Mimecast, Proofpoint).
  
• Experience supporting regulated organizations ensuring compliance with industry standards (e.g., GDPR).
  
• Ability to collaborate with colleagues across the enterprise and to work effectively in matrixed, geographically distributed teams around the globe.
  
• Soft Skills: structured mindset, attention to detail, proactive problem-solving, self-motivation, ability to work under pressure, and collaborative cross-functional teamwork.
  

We are committed to supporting your development, advancing your career, and providing benefits that matter to you. Our Alter Domus Academy offers six learning zones and resources from LinkedIn Learning.

• 
  
• Support for professional accreditations
  
• Flexible arrangements, generous holidays, plus an additional day off for your birthday
  
• Continuous mentoring along your career progression
  
• Active sports, events and social committees across our offices
  
• 24/7 support from our Employee Assistance Program
  
• Opportunity to invest through our Employee Share Plan
  
• Additional local benefits depending on location
  

We are committed to equal opportunity and an inclusive culture where everyone can bring their whole self to work. We celebrate diversity and provide a welcoming recruiting and onboarding process. If you require accommodations in the recruitment process, please contact our hiring team. xcfaprz Alter Domus is an Equal Opportunity Employer; all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability, or protected veteran status.

(Alter Domus Privacy notice can be reviewed via Alter Domus webpage: )