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What is CASB in cybersecurity?

The importance of cloud technology in business operations has seen an upward trend in the last few years. While cloud deployment provides many benefits to enterprises, it has also introduced new risks, such as reduced visibility, increased complexity in ensuring security, and the use of unsanctioned cloud applications by users. These risks pose a threat to the security and credibility of organizations and may result in severe damage. The immediate mitigation of risks is necessary, and this is where cloud access security broker (CASB) comes into the picture.

CASB is an on-premises or cloud hosted software or appliance that acts as a gatekeeper and monitors the interaction between users and cloud service providers (CSPs).

CASBs provide visibility into the activities and tries to empower enterprises to address their share of security responsibility in terms of access to infrastructure as a service, platform as a service, and software as a service environments, commonly referenced as Iaas, PaaS, and Saas, respectively.

Apart from providing visibility, CASB also allows enterprises to control access by enforcing policies and extending their on-premises security policies to the cloud.

Why is CASB important?

  • Regulate user access: Since cloud services are hosted out of the perimeter of organizations, exercising control over user activities becomes difficult. CASB enables organizations to enforce security policies and regulate users' access to data stored on the cloud.
  • Protect sensitive data: CASB can be used to monitor sensitive data in-transit and protect the contents of the data through encryption.
  • Stop data abuse: CASB helps identify and restrict unauthorized attempts to access, and transmit data from and to the cloud.
  • Monitor Shadow IT: CASB keeps a close eye on unsanctioned cloud applications or "shadow IT" applications being accessed by users.
  • Ensure compliance: Using CASB, organizations can meet the data security and access requirements of various IT compliance mandates.
  • Track usage: CASB audits the usage of cloud services for budgeting purposes.

CASB's functionality can be described in terms of its four cornerstones.

4 cornerstones of CASB

  • Visibility
  • Threat detection
  • Data security
  • Compliance


Most CSPs offer very little in terms of audit and logging. CASBs overcome these limitations by providing details about the traffic of data being moved between the organization and cloud providers. This helps organizations better understand what sanctioned and unsanctioned cloud services are being utilized by users, and guides them to safer alternatives. User, location, device, application and quantity of data are some of the metrics that can be extracted, to monitor the usage of cloud services by users.

Threat detection

Organizations need to regulate the access of critical data from cloud services and detect exfiltration of data by malicious actors with stolen credentials or negligent users trying to access sensitive information. CASBs can observe and register patterns of usage exhibited by users and form a baseline, using user entity and behavior analysis (UEBA). Any deviation from the baseline gets flagged as an anomaly, helping organizations spot and mitigate threats at the earliest. CASB's out-of-the-box capabilities, such as dynamic malware analysis and threat analysis, detect the presence of malwares.

Data security

While the cloud has made sharing data with people a job easier than ever, it has also put traditional data leak prevention (DLP) tools into jeopardy because cloud services do not fall under their purview. A CASB can inspect sensitive data being moved from to and from the cloud, between cloud services, and within the cloud. These observations help organizations identify and stop attempts to leak sensitive information. CASBs can also provide contextual access control that can regulate application access to users based on factors such as role, device, and geography.


While switching to cloud-based services, an important aspect that should be taken into consideration is compliance. Regulations such as PCI-DSS, HIPAA, GDPR and others ensure that organizations have proper security systems in place to store and handle sensitive data. CASBs provide you with a range of options to identify and control the flow of personal data, monitor high-risk activities, and detect shadow IT applications to ensure adherence to privacy regulations and compliance mandates.

Use cases of CASB:

  • Context-based access control
  • Configuration auditing
  • Threat detection and mitigation
  • UEBA
  • DLP
  • Malware detection
  • Cloud governance and risk assessment
  • Data encryption
  • Cloud access policy enforcement
  • Compliance reporting and management
  • Single sign-on (SSO)

CASBs are fast-becoming a crucial part of enterprise security. However, it is important to note that CASBs are designed to complement other security solutions in the process of achieving a completely cyber-secure environment.

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