Sean Johnstone

Sean Johnstone

Senior Security Engineer | CyZen

One Liberty Plaza
165 Broadway, Floor 21
New York, NY 10006
p 212.897.6453
f  212.842.7001

Sean Johnstone is a Senior Security Engineer at CyZen, a Friedman LLP company. He has served a wide range of clients in industries, which include not-for-profits, banking/financial services, private equity, fashion, law firms, healthcare, smart device manufacturers and various public sector entities.


Sean began his career in JPMorgan’s anti-money laundering division. Thereafter, he leveraged his JPMorgan experience upon entering the cybersecurity space at K2 Intelligence. There he consulted both international and domestic clients on strategies for adhering to strict USA AML laws and regulations. He has fostered powerful client relationships through his proactive, innovative and tailored approach combined with his passion for helping non-technical audiences understand the ways in which cybersecurity can directly impact them and their businesses. 

Sean’s expertise includes:

  • Leading critical vulnerability assessments in order to highlight a company’s technical risks and exposures
  • Conducting penetration tests to help clients validate discovered vulnerabilities and provide recommendations to ensure the risks are technically mitigated
  • Protecting clients’ network devices through Cyzen’s endpoint monitoring solution
  • Performing network security architecture reviews on clients’ multi-layered organization networks to zero in on potential gaps
  • Spearheading cyber security awareness training for clients throughout the northeast to lay the foundation for vital cybersecurity protection, using a targeted approach that leverages best practices and draws from his in-depth industry knowledge
  • Collecting data through Open-source Intelligence (OSINT) to identify potential client exposure in publicly accessible information