Duo Security, a part of Cisco, offers a cloud-based access management system that ensures secure connections for all users and devices, aiming to prevent unauthorized access. It features multi-factor authentication (MFA), single sign-on (SSO), and adaptive access policies, which allow customization of user access based on specific security standards. Designed to serve organizations of all sizes, Duo Security integrates with various platforms, offering security solutions that support a zero-trust security model.