Cloud Access Security Broker (CASB)

What are the 4 pillars of a CASB?

Cloud access security brokers are built on four foundational pillars that together provide comprehensive cloud security. These pillars represent the core functionalities that every robust CASB solution should offer to effectively secure cloud environments. Each pillar addresses a specific aspect of cloud security risk, and when implemented together, they create a holistic approach to protecting data and applications in the cloud.

Visibility 

The visibility pillar focuses on providing comprehensive insights into cloud service usage across an organization. This includes discovering all cloud applications in use (both authorized and unauthorized), identifying who is accessing them, what data is being shared, and from which devices. Visibility helps security teams detect shadow IT—cloud services adopted without IT department approval—and understand usage patterns that could indicate potential security risks.

Compliance

The cloud compliance pillar ensures that cloud service usage adheres to regulatory requirements and internal security policies. CASBs help organizations meet various compliance standards (such as GDPR, HIPAA, PCI DSS) by monitoring data handling practices, implementing data residency controls, providing audit logs, and offering reporting capabilities. This pillar is crucial for industries with strict regulatory frameworks and helps organizations avoid costly penalties associated with non-compliance.

Data security

The data security pillar focuses on protecting sensitive information stored in or transmitted to cloud services. CASBs implement data loss prevention (DLP) techniques, including content inspection, classification, and encryption. These capabilities allow organizations to detect and prevent unauthorized sharing of sensitive data, apply rights management to protect documents, and enforce encryption policies for data at rest and in transit, ensuring that sensitive information remains secure even when stored in third-party cloud environments.

Threat protection

The threat protection pillar guards against malicious activities targeting cloud services and data. CASBs utilize user and entity behavior analytics (UEBA) to detect anomalous behavior that might indicate compromised accounts, insider threats, or data exfiltration attempts. They also provide protection against malware, enforce adaptive access controls based on risk scores, and enable security teams to respond quickly to potential threats by blocking suspicious activities or initiating additional authentication requirements.

How does a CASB work? 

A CASB works by integrating into an organization's infrastructure and connecting to cloud services through various deployment modes. The primary methods include:

1. API-based connectivity: CASBs connect directly to cloud service providers' APIs to monitor activities and enforce policies asynchronously. This approach provides deep visibility into data already stored in cloud services but may have limitations for real-time enforcement.
2. Forward proxy: In this deployment mode, all traffic is directed through the CASB before reaching cloud services. This allows for real-time policy enforcement and inspection but requires client configuration or agent installation.
3. Reverse proxy: The CASB acts as an intermediary that users access when connecting to cloud services, typically through URL rewriting. This approach doesn't require client configuration and works well for browser-based access.
4. Hybrid deployment: Most enterprise CASB implementations use a combination of these methods to ensure comprehensive coverage and maximize security benefits.

Once deployed, CASBs analyze traffic patterns, inspect content, apply security policies, encrypt sensitive data, and generate alerts for potential security issues. Advanced CASBs leverage machine learning to improve threat detection and adapt to evolving security challenges in the cloud environment.

Common CASB use cases

CASBs address numerous cloud security challenges across organizations. The most common use cases include: 

1. Shadow IT discovery and risk assessment: Identifying unauthorized cloud applications and evaluating their security risks to determine whether to sanction, restrict, or block their use.
2. Data loss prevention: Preventing sensitive information from being improperly shared or leaked through cloud services by enforcing content-aware policies.
3. Compliance enforcement: Ensuring cloud usage meets regulatory requirements by monitoring data handling practices and generating compliance reports.
4. Account compromise detection: Identifying suspicious login attempts, unusual access patterns, or potential account takeovers through behavioral analysis.
5. Secure access to cloud services: Enforcing contextual access controls based on user identity, device health, location, and sensitivity of the resource being accessed.
6. Malware prevention: Scanning uploaded and downloaded files for malicious content to prevent malware from spreading through cloud services.
7. Third-party risk management: Controlling which third-party applications can connect to corporate cloud services and what permissions they're granted.
8. Data encryption and tokenization: Protecting sensitive information by encrypting or tokenizing data before it's stored in cloud services.

CASB vs. other security solutions

While CASBs play a crucial role in cloud security, they're part of a broader security ecosystem that includes various specialized solutions.

By comparing CASBs with related solutions, security teams can better determine where each fits within their security architecture and how they work together to provide defense in depth. Here's how CASBs compare to other common security technologies:

CASB vs. secure web gateway (SWG)

While both technologies filter web traffic, SWGs primarily focus on protecting users from web-based threats when accessing internet sites. CASBs specialize in securing cloud service usage with deeper visibility into cloud applications and data. SWGs typically operate at the URL level, while CASBs provide application-level controls specific to cloud services. Many organizations use both solutions together for comprehensive protection.

CASB vs. zero trust network access (ZTNA)

ZTNA focuses on providing secure access to applications based on identity and context, following the "never trust, always verify" principle. CASBs complement ZTNA by adding cloud-specific security controls and data protection capabilities. ZTNA solutions control access to applications, while CASBs provide visibility into what users do with those applications and the data within them.

CASB vs. cloud firewall

Cloud firewalls focus on network-level protection for cloud infrastructure, monitoring traffic flows and enforcing access rules. CASBs operate at the application layer with greater emphasis on data security and user behavior. Cloud firewalls protect the cloud infrastructure itself, while CASBs protect the data and applications running in cloud environments.

CASB vs. security information and event management (SIEM)

SIEMs collect and analyze security event data from multiple sources to detect threats and aid in incident response. CASBs generate cloud-specific security events that often feed into SIEMs for broader security analysis. SIEMs provide the analytics platform for security monitoring, while CASBs deliver cloud-specific controls and visibility that contribute valuable data to SIEM systems.

CASB vs. data loss prevention (DLP)

Traditional DLP solutions focus on preventing data leakage across endpoints, networks, and storage. CASBs incorporate cloud-specific DLP capabilities tailored to cloud applications and services. Enterprise DLP systems often integrate with CASBs to extend their policies to cloud environments, creating a unified data protection strategy across on-premises and cloud resources.

Key benefits of CASBs

Implementing a CASB solution offers organizations several critical advantages in securing their cloud environments: 

1. Comprehensive cloud visibility: Gain complete insight into all cloud applications being used across the organization, including shadow IT, allowing for better risk management and resource allocation.
2. Consistent security policy enforcement: Apply uniform security controls across multiple cloud services, ensuring that security standards are maintained regardless of where data resides.
3. Data protection across cloud services: Enforce data security policies to prevent leakage of sensitive information through cloud applications, maintaining control over corporate data even when it leaves the traditional network perimeter.
4. Threat protection and risk reduction: Detect and respond to cloud-specific threats, including compromised accounts, insider threats, and malicious insiders, reducing the organization's overall security risk posture.
5. Regulatory compliance support: Meet compliance requirements for data handling in cloud environments with enhanced monitoring, control capabilities, and detailed audit trails.
6. Secure cloud adoption: Enable the business to safely embrace cloud technologies and their benefits while maintaining appropriate security controls and risk management.
7. Cost optimization: Identify redundant or unused cloud services, allowing organizations to consolidate applications and potentially reduce licensing costs.
8. Improved incident response: Detect security incidents faster with real-time monitoring of cloud activities and automated alerts for policy violations or suspicious behaviors.

By implementing a CASB solution, organizations can confidently accelerate their cloud adoption initiatives while maintaining the security and compliance controls necessary in today's threat landscape.