Nisos Group

Brief Overview

Nisos is a technology enabled cyber security services company, created by former operations officers from the Intelligence Community specializing in Active Defense. Nisos specializes in Active Defense services and helps to secure and defend client networks and attribute threats against their organization.


Washington, DC
Tel: (703) 621 – 2364


Justin Keefe serves as Co-founder and Executive Director for Nisos Group. Landon Winklevoss serves as Co-founder and Executive Director for Nisos Group. Sean Weppner serves as Chief Strategy Officer for Nisos Group. Vincas Cizunas serves as CTO for Nisos Group.


The company was formed in 2015 and is comprised of former Intelligence Community operators trained in covert and clandestine operations. The company has operations in Washington, LA, Denver, and New York.

Key Competitors

Redacted, Mandiant

Products and Services

Nisos provides services o their clients by fusing their on-the-network and off-the-network capabilities.

• M&A Diligence
• Adversarial Attribution
• Insider Threat Detection & Mitigation
• Incident Response
• Attack Simulation
• Compromise Assessment
• Asset Protection
• Executive Protection