A Cloud Access Security Broker (CASB) is a security solution that acts as an intermediary between users and cloud service providers, enabling organizations to extend their security policies to the cloud. As enterprises increasingly adopt Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS), CASBs provide critical visibility, control, and protection across these environments. They are essential for addressing the security challenges of shadow IT, data leakage, and cloud compliance.

‍

CASBs typically deliver four key pillars of functionality:

1. Visibility – Identifying all cloud services in use and understanding how data is being accessed and shared.
2. Data Security – Enforcing data loss prevention (DLP) policies, encryption, and tokenization to protect sensitive information.
3. Threat Protection – Detecting and mitigating cloud-specific threats such as malware, compromised accounts, and insider abuse.
4. Compliance – Assisting organizations in meeting regulatory requirements such as GDPR, HIPAA, and PCI DSS through monitoring, reporting, and policy enforcement.

CASBs operate using various modes, including API-based integration, reverse proxy, forward proxy, and agent-based deployment, each suited to different use cases and levels of control. Modern CASBs often integrate with identity providers (IdPs), security information and event management (SIEM) systems, and endpoint protection platforms.

‍

By implementing a CASB, organizations gain deeper insight into user behavior, prevent unauthorized access, and ensure consistent enforcement of security policies across sanctioned and unsanctioned cloud applications. As cloud adoption continues to grow, CASBs are a vital part of a Zero Trust architecture, helping enterprises maintain control over data and reduce risk in an increasingly perimeterless environment.

‍

Read more about Nudge Security v. CASB →