CSIS Security Group A/S is a European cybersecurity company founded in Copenhagen in 2003. The company operates with over 130 employees representing more than 20 nationalities across offices in Copenhagen, Skanderborg, London, Stockholm, and Amsterdam. CSIS is owned by Allurity AB, which is part of Trill Impact.

The company provides intelligence-driven detection and response services, threat intelligence, prevention services, incident response, and 24/7 managed security services. Their threat intelligence capabilities have been recognized by Gartner Group. CSIS serves law enforcement agencies, government entities, businesses, and media organizations.

In 2024, SecAlliance, a company specializing in intelligence services, joined CSIS. The company operates as part of the Allurity family, which comprises 11 companies across Europe with 42 offices in 18 countries and approximately 770 cybersecurity professionals.

CSIS maintains a flat organizational structure with limited bureaucracy and emphasizes an open-minded, team-oriented culture. The company's stated ambition is to become a prominent European provider of tech-enabled cybersecurity and intelligence services. Their service portfolio focuses on actionable intelligence and helping customers optimize their internal security resources through managed services.