What is one of the crucial roles of CASB in cloud security?

In the context of cloud security, a Cloud Access Security Broker (CASB) plays a pivotal role in enforcing security policies. This involves monitoring user activities and data transfers between the cloud service provider and the organization's on-premises infrastructure. A CASB helps ensure compliance with security policies by applying necessary controls, such as authentication, encryption, and user behavior analytics.

By enforcing security policies, a CASB acts as a mediator between users and cloud service providers, giving organizations visibility and control over their data in the cloud. This is particularly important for managing risks associated with shadow IT and ensuring that sensitive information is protected in line with regulatory requirements and internal guidelines.

The other options relate to tasks that are not typically within the core functionality of a CASB. For instance, implementing firewall rules is more aligned with traditional network security measures rather than cloud-based policy enforcement. Performing data backups is generally handled by dedicated backup solutions or cloud service features themselves. Creating user accounts is typically the responsibility of Identity and Access Management systems rather than a CASB, which focuses more on policy enforcement and oversight of cloud service use.