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Cloud Access Security Broker (CASB)

A Cloud Access Security Broker (CASB) is a security solution that provides visibility and control over data and activity in Software-as-a-Service (SaaS) applications, protecting organizations from shadow IT, data leakage, and compliance violations.

What is CASB?How it typically works?Common techniquesImpactFurther reading

What is CASB?

As organizations adopt SaaS platforms like Microsoft 365, Salesforce, and Google Workspace, they face new risks. Employees may use unauthorized applications, sensitive files may be shared externally, and compliance requirements may be violated. CASBs solve these challenges by acting as a policy enforcement point between users and cloud applications. For SecOps, CASBs provide both visibility into SaaS usage and the ability to apply consistent security controls, bridging the gap between traditional perimeter defenses and cloud environments.

How it typically works?

  1. Discovery: CASB identifies all SaaS applications in use, including shadow IT.
  2. Policy enforcement: it applies security controls such as access restrictions and data loss prevention.
  3. Monitoring: CASB continuously inspects traffic for risky activity.
  4. Threat detection: anomalous behavior like unusual downloads or logins is flagged.
  5. Control: depending on policy, CASB can block, allow, or quarantine actions.

Common techniques

  • Visibility tools: inventory SaaS applications used across the enterprise.
  • Access control: enforce login requirements and MFA for cloud apps.
  • Data loss prevention (DLP): stop sensitive files from leaving approved boundaries.
  • Threat protection: detect compromised accounts and insider threats.
  • Shadow IT detection: identify unsanctioned SaaS usage.
  • API-based CASB: integrates directly with SaaS APIs for deeper visibility.
  • Proxy-based CASB: sits in the traffic path for inline enforcement.

Impact

CASBs help organizations embrace SaaS without sacrificing security. They reduce the risk of data breaches, protect against insider threats, and ensure compliance with regulations.

However, CASB deployment requires careful integration with identity systems and network infrastructure. Poorly tuned CASBs may frustrate users or slow down workflows. For SecOps, CASBs are a vital complement to Zero Trust, enabling visibility and control in the cloud era.

Further reading

Related topics

CSPMZero Trust SecurityIdentity and Access Management (IAM)