What’s a Cloud Access Security Broker? CASB Components & Use Cases

What is CASB

Hitesh J

Cloud Access Security Brokers (CASB) are a type of security software that aids in managing and protecting data stored in the cloud. According to Gartner, businesses should look for a “Goldilocks” CASB solution, which provides just-right capabilities for SaaS applications and Cloud infrastructure.

This article will discuss the definition, how it works, why we need it, components, and various use-cases of CASB.

What is CASB?

A Cloud Access Security Broker (CASB) is a piece of cloud-hosted software or on-premises software or hardware that acts as a conduit between users and cloud service providers.

Software-as-a-Service (SaaS), platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS) settings all benefit from a CASB's ability to close security vulnerabilities. A CASB allows enterprises to extend the reach of their security rules from their existing on-premises architecture to the cloud and establish new policies for cloud-specific context, in addition to giving visibility. CASBs have become an essential aspect of organizational security, allowing companies to access the cloud safely while safeguarding sensitive company data.

The CASB acts as a policy enforcement center, combining several types of security policies and applying them to anything your company uses in the cloud—regardless of what kind of device is trying to access it, such as unmanaged cellphones, IoT devices, or personal laptops.

With the development of BYOD and the prevalence of unsanctioned employee cloud usage or Shadow IT, the ability to monitor and manage cloud apps like Office 365 has become critical to achieving business security goals.

Rather than outright forbidding cloud services and jeopardizing employee productivity, a CASB allows organizations to take a more nuanced approach to data protection and policy enforcement, allowing them to use time-saving safely, productivity-enhancing, and cost-effective cloud services.

How does CASB Work? 

CASBs ensure that network traffic between on-premises devices and the cloud provider adheres to the security requirements of the enterprise. Cloud access security brokers are valuable because they may provide insight into cloud application use across platforms and identify unauthorized use. This is particularly crucial in regulated businesses.

CASBs use autodiscovery to identify cloud apps in use and high-risk applications, users, and other essential risk characteristics. Security access brokers for cloud access can impose various security access constraints, such as encryption and device profiling. When single sign-on is not possible, they may also provide other services such as credential mapping.

Why do We need a CASB?

We get asked this query a lot: “I recently spent $200K on a firewall.” “Why would I need cloud security?” you might wonder. Consider the following scenario: Are there locks on your home's doors and windows to keep burglars out? But what happens if a thief breaks in? For this reason, many people invest in a home security system. It notifies you if there has been a breach, where the intruder entered from, and, in some situations, what the intruder is doing in real-time. It activates alarms and notifies the appropriate authorities, allowing the effects of the break-in to be minimized.

Cloud security accomplishes this for businesses that use cloud apps to generate, collaborate, and store data in the cloud. A firewall can help safeguard the perimeter of your network, but cloud apps don't run on your network; they do so on the public cloud. So, like the lock on your front door, your firewall and/or gateway makes it more difficult for burglars to gain access, deterring the less motivated or sophisticated ones.

However, once a cybercriminal gets past the perimeter, they have access to your information. They make use of this access to download, copy, and redistribute data for their evil reasons. Your employees may never be aware of a compromise if you don't use cloud security. Your company's intellectual property, financial information, and personally identifying information of customers and workers could all be sold for profit without you even realizing it.

When a criminal gets beyond your firewall perimeter and gains access to your cloud environment, the correct CASB security system will start to send out warnings and alarms. To prevent data theft, a cloud security platform can execute a range of operations automatically. It can restrict access to a user's account, revoke viewing and sharing permissions for specific sorts of documents, and more. IT security administrators also obtain valuable information on how the criminal gained access to the environment, which files and folders were affected, and more.

Cloud security isn't an option; it's a requirement. Without cloud security, your company will become increasingly exposed as more data is created, stored, and shared on the cloud. Investing more money in a more expensive firewall will not make it more successful at safeguarding things it doesn't have control over.

Components of CASB

CASB has evolved from its beginnings as a response to Shadow IT to encompass functions that may be divided into four categories:


Large organizations may have many employees accessing a variety of applications in a variety of cloud settings. Business data is no longer bound by its governance, risk, or compliance requirements when cloud usage is hidden from IT. A CASB solution gives comprehensive insight over cloud app activity, including user information such as device and location information, to protect users, personal data, and intellectual property. The cloud discovery analysis generates a risk evaluation for each cloud service in use, allowing enterprise security professionals to determine whether or not to enable access to the app. This data can also be used to create more granular controls, such as providing different access levels to applications and data based on the device, location, and job function of an individual.


While organizations can outsource all of their systems and data storage to the cloud, they are still responsible for ensuring that the privacy and security of their data are protected. Cloud access security brokers can assist with cloud compliance by addressing a range of legislation such as HIPAA and regulatory standards such as ISO 27001, PCI DSS, and others. A CASB solution can identify the areas of most risk in terms of compliance and direct the security team as to where they should spend their efforts to remedy them.

Data protection

Many of the hurdles to efficient remote collaboration have been addressed as a result of cloud adoption. However, while seamless data migration might be beneficial, it can also come at a high cost for firms that want to protect sensitive and secret information. While on-premises DLP solutions are intended to protect data, their capabilities sometimes do not extend to cloud services and lack cloud context. IT can observe when critical content is flowing to or from the cloud, within the cloud, and cloud to cloud, thanks to the combination of CASB and advanced DLP. Enterprise data leaks can be reduced by installing security features such as data loss prevention, access control, information rights management, encryption, and tokenization.

Threat Protection

Employees and third parties with stolen passwords can leak or steal critical data from cloud services, whether through negligence or malicious intent. CASBs can construct a comprehensive perspective of usual usage patterns and utilize it as a reference point to help discover aberrant user behavior. CASBs can detect and mitigate attacks as soon as someone tries to steal data or get unauthorized access using machine learning-based user and entity behavior analytics (UEBA) technologies. The CASB can leverage capabilities like adaptive access control, static and dynamic malware analysis, prioritized analysis, and threat intelligence to block malware arriving from cloud services.

Use Cases of CASB

User activities can be captured in the custom cloud and on-premise apps

Custom applications that serve business-critical operations are typical in organizations. IaaS platforms have increased the accessibility and flexibility of custom application adoption and development, often at the expense of security and compliance standards. A CASB can help you monitor and act in real-time on various activities across these apps in your organization, ensuring that you know the location and actions made on sensitive resources. Microsoft Cloud App Security allows you to achieve this deep visibility and parity across your cloud apps by employing Azure Active Directory connectors.

To secure your IaaS environments from risks, keep an eye on user activity

The impact of a user with the capacity to change your IaaS environment can be enormous and directly influence your ability to run your business since vital corporate resources such as the servers that power your public website or service you provide to clients can be jeopardized. Microsoft Cloud App Security monitors and analyses IaaS platform behavior, including custom applications. A robust UEBA engine analyses these activities to discover aberrant usage associated with compromised accounts, insiders, and privileged users. It will notify you of incidents such as the odd deletion of virtual machines, which could indicate a real-time attempt to control your environment.

Examine the setup of your IaaS environments

The rise of automation and user self-service in IaaS services necessitates ongoing auditing to guarantee that cloud instances are correctly set up. Because there is so much data, a single mistake can expose thousands of records and be undiscovered for a long time. You may execute a security configuration assessment across your IaaS deployments using a CASB‘s Cloud Security Posture Management capabilities. It helps you discover essential data leak sources, such as publicly accessible AWS S3 buckets, and makes precise recommendations for improving your overall security configuration.

Threats from privileged accounts can be detected

Attackers compromise user accounts through methods such as phishing, password spraying, and breach replay, with the ultimate goal of gaining control over a privileged account, making these the most at-risk accounts and the most vital to monitor. A CASB will notify you of a variety of behaviors that indicate a privileged account has been compromised. Mass impersonation by a single user, login from a new country with an admin account, or abnormal activity from an MSSP admin is all relevant signal.

Proper hybrid identity threat protection is provided by the unified, identity-based Security Operations experience. And, to guarantee that alarms are examined quickly, Microsoft Cloud App Security offers an investigation priority—a list of accounts that are suggested for rapid inspection based on variables such as a user's access level.

Detect risks from within your organization's users

Many scenarios in which users with legitimate access to your cloud resources become a threat to your organization. Whether an employee is looking to leave your organization with valuable information or external partners with access to your environment are attempting to exfiltrate relevant sensitive data for competitive gain. Individual users' abnormal conduct can be detected with the use of a CASB. It will notify you of occurrences like mass downloads by an internal user or strange, repeated activity from your external user group, highlighting insider risks and allowing you to act immediately to suspend the necessary user accounts to prevent data exfiltration.

Final Thoughts

Due diligence does not end with a thorough examination of all vendor offerings. Many cloud access security broker (CASB) vendors provide free trials and cloud audits to help you understand your company's cloud usage and how the CASB will integrate into your entire security infrastructure. You'll want to investigate if the CASB interfaces with other components of your cloud security strategy, such as DLP, SIEM, firewalls, secure web gateways, and more, and figure out where the ideal integration points are. You'll also be able to integrate the CASB with some SSO (single sign-on) or IAM (identification and access management) systems; it's best to decide whether and how to use these features as soon as possible.