What are CASBs? Cloud Access Security Brokers Explained

A Cloud Access Security Broker is a widely used security solution. These brokers act as a security checkpoint between end users and cloud service providers. Their main role is to make sure that security policies are consistently applied across cloud environments. These policies define who can access specific cloud services, applications, or data, primarily based on roles, permissions, and user identities.

As brokers, CASBs are located between users and their cloud services to help organizations maintain control over their data. These brokers support key features such as: 

• Visibility
• Threat protection
• Data security
• Compliance management

These features all help to safeguard various cloud environments (e.g., SaaS, PaaS, IaaS) against cyber threats and data breaches.

In this article, we will explore how Cloud Access Security Brokers (CASBs) function, their key capabilities, and best practices for implementation to enhance cloud security and ensure compliance in multi-cloud environments.

Why do we need CASBs?

Nowadays, it is no easy task  to secure data across various cloud-based applications and multiple devices. Most of the traditional security systems that are in use are not sufficient — they often struggle to protect against the latest security threats.

That’s why users are moving towards solutions like CASBs: these help enforce security policies in a way that suits the modern workforce. These brokers are more secure than traditional methods and provide the flexibility needed to balance data security with user access.

Cloud service providers are responsible for securing your underlying infrastructure. However, they are not responsible for securing the user's operating system, applications, and data. That responsibility solely lies with the user. This shared responsibility model often leads to misunderstandings, where users mistakenly believe their cloud workloads are fully protected by the provider. CASBs help to fill this gap by protecting the users' applications and data. 

More services are now moving from on-premises to the cloud. These migrations have rapidly increased the need for security solutions like CASB. CASBs help organizations meet compliance requirements, protect against cyber threats (eg;- zero-day exploits), and help employees safely use cloud services without adding unnecessary risks. Due to these reasons, the use of CASB solutions has rapidly increased, and people nowadays are more curious about its uses.

Who needs CASBs?

Organizations that use cloud services can greatly benefit from the use of a CASB in their systems. Companies that struggle with shadow IT (where employees use unauthorized applications) will find CASB solutions valuable for gaining control and visibility over these unmonitored cloud activities.

Additionally, highly regulated industries, such as healthcare, finance, and government, need CASBs to ensure compliance with strict data protection laws and industry standards. Businesses that manage sensitive or confidential information can use CASBs to enforce data loss prevention (DLP) policies and secure data transfers to and from the cloud.

How do CASBs work?

In this section let's try to understand how a CASB solution works by breaking the whole process into 3 major steps.

1. Discovery

CASB identifies all cloud applications being used within the organization. This includes both sanctioned and unsanctioned ones. It also tracks which employees are using these applications. This process helps the organization understand the full scope of its cloud usage.

2. Classification

Next, the CASB evaluates each identified application. It determines

• What kind of data is being handled by the app?
  
• How the data is being shared.
• Assesses the risk level associated with using the application.
  

This step is important for understanding the potential vulnerabilities and the security posture of each cloud service.

3. Remediation

After the risk assessment, CASB creates a security policy for the organization. This policy is designed to address specific security needs and can automatically detect and respond to any threats or policy violations that occur. Also, CASBs provide extra layers of protection through features like malware prevention and data encryption.

Security features offered by CASB

CASB provides a range of security features designed to protect data, control access, and secure cloud environments. The below list provides some of the key security capabilities offered by CASBs.

• Data loss prevention: Prevents sensitive data loss and data leaks.
• Malware detection: Identifies and blocks malicious software before it can harm the network.
  
• Adaptive access control: Controls user access based on contextual factors like location, device, or user behavior.
  
• Behavior analytics: Monitors and analyzes user behavior to detect and respond to unusual activities that may indicate a threat.
  
• Web application firewalls: Helps to protect web applications by filtering and monitoring HTTP traffic between a web application and the internet.
  
• Authentication: Authenticate users by verifying user identities. It uses multiple verification factors to make sure that only authorized users can access sensitive data.
  
• Collaboration control: Manages and secures collaboration tools. This helps in safe sharing and communication within the organization.
  
• Encryption: Helps in data protection by converting data into a secure format that is unreadable without the proper decryption key.
  
• Single sign-on and IAM integration: Integrates with SSO and IAM systems to provide authentication and access management across cloud services.
  

4 pillars of CASBs

​​Cloud Access Security Brokers operate on four foundational pillars. Adapting to these pillars helps organizations to maintain control, protect data, and meet compliance requirements in the cloud.

Visibility

CASBs provide visibility into cloud app usage across an organization. This includes both managed and unmanaged applications. This visibility includes: 

• Identifying users, devices, and locations.
• Supporting IT teams to monitor and manage cloud services effectively.
  

With visibility information, organizations can assess risks associated with each cloud service and decide whether to allow or block access.

Compliance

Being compliant with regulatory standards is very important to build trust in your organization among its users. CASBs help maintain compliance with HIPAA, PCI DSS, and ISO 27001, etc. They identify high-risk areas related to compliance and guide security teams on how to mitigate these risks.

Data security

CASBs help to improve data security by extending data loss prevention capabilities to the cloud. They track the movement of sensitive data to, from, and within cloud services, and apply required security measures (eg:- encryption, access control, and collaboration control). This helps to keep confidential information protected and minimizes the risk of data breaches and leaks.

Threat protection

CASBs respond to internal and external threats and help to detect and protect against threats. They use advanced technologies during this process. For example, they use machine learning-based User and Entity Behavior Analytics, malware analysis, and adaptive access control to identify and neutralize threats in real time. 

How to implement a CASB solution

To implement a proper CASB solution as the first step you need to choose the deployment model that best fits your organization's needs. CASBs are typically deployed in the cloud, though on-premise options are available.

The three main deployment models are: 

• API scanning. Ideal for monitoring data at rest in sanctioned applications but doesn't provide real-time protection.
• Forward proxy. Offers real-time data loss prevention for both sanctioned and unsanctioned applications but is limited to managed devices and cannot scan data at rest.
  
• Reverse proxy. Provides real-time DLP for sanctioned applications and works on both managed and unmanaged devices by redirecting user traffic. For maximum flexibility and security, consider a multimode CASB that combines all three models.
  

Benefits of CASBs

Various sections in this article have already suggested the benefits of CASBs. Let’s revisit and summarize the key benefits that make CASBs an important solution for privacy-minded organizations.

• Provides visibility into cloud applications by giving organizations a comprehensive view of cloud activity.
  
• Protects sensitive information by enforcing policies that prevent unauthorized sharing of data such as financial records, proprietary information, and personal identifiers.
  
• Allows detailed management of cloud usage and helps organizations to limit or allow access based on factors like employee status or location, and governs specific activities, services, or applications.
  
• Manages cloud security by allowing IT teams to manage all security services through a single vendor and dashboard, reducing complexity and improving efficiency.
  
• Ensures that all security technologies work seamlessly together, reducing the challenges of managing multiple platforms from different vendors.
  

Challenges of CASBs

After reading about the ins and outs of CASB and reading benefits, it is important to consider the challenges involved.

Scalability. One challenge of using a CASB is scalability. As organizations grow, their cloud usage and data volumes increase. So it requires the CASB to scale accordingly. Therefore companies must make sure that their chosen CASB vendor can handle this expansion without compromising performance or security.

Threat mitigation. Another challenge is mitigation. While CASBs can identify security threats, not all of them have the capability to actively stop these threats. This limitation can reduce the effectiveness of a CASB. Therefore companies must choose a solution that includes robust threat mitigation features.

Systems integration and data privacy. Integration and data privacy are also significant concerns. For a CASB to work properly, it must integrate with all of the company’s systems and infrastructure. Without complete integration, the CASB might miss unauthorized IT activities or potential security risks.

Also, organizations need to guarantee that the CASB vendor maintains strict data privacy standards, particularly if they move customer data to the cloud, to avoid adding another layer of risk to sensitive information.

(Related reading: third-party risk management.)

Factors to consider when picking a CASB

When selecting a CASB solution, consider whether it aligns with your specific use cases and goals. Conduct thorough proof of concepts (POCs), gather insights from cybersecurity experts, or consult with similar organizations to choose a good fit. Check whether the selected solution can grow and adapt with your organization as cloud usage and threats keep on evolving. Further, it should help you to keep your cloud security and compliance policies up to date.

It is also important to evaluate how well the CASB integrates with your existing security infrastructure. For example with DLP, SIEM, firewalls, and secure web gateways. Running a trial to verify compatibility with your cloud infrastructure and assessing the CASB's ability to handle essential functions like encryption, authentication and authorization can further ensure a good match.

Finally, pay attention to selecting a solution that not only protects SaaS but also offers comprehensive security for IaaS environments, including threat protection, activity monitoring, and DLP controls.

To wrap-up

Cloud Access Security Brokers are very popular among organizations that are facing cloud security challenges. These solutions help businesses to safeguard against cyber threats. They help to protect your sensitive data. They also prevent threats and help in compliance management. The importance of CASBs continues to rise as more companies are moving from on-premise to cloud environments.