A Cloud Access Security Broker (CASB) is a cloud security solution designed for cloud computing environments that sits between users and cloud services to enforce data protection, access control, threat detection, and compliance policies.
CASBs help organizations secure cloud applications like SaaS, IaaS, and PaaS (offered by various cloud service providers)—but may fall short in securing SaaS app configurations, which is where SaaS Security Posture Management (SSPM) tools come in.
What Does a CASB Do?
A CASB acts as a cloud security policy enforcement point, delivering visibility, control, and protection between users and cloud-based services. CASB platforms help organizations:
- Monitor cloud application usage to gain visibility into user activities across various cloud platforms
- Monitor user behavior to detect anomalies and enforce security policies
- Discover shadow IT
- Enforce access controls
- Protect sensitive data from leakage
- Detect threats across cloud environments
- Maintain regulatory compliance with industry regulations
By integrating with cloud apps via proxy, agent, or API, CASBs enable consistent security across both sanctioned and unsanctioned applications.
How CASBs Work
CASBs inspect traffic and user behavior between devices and cloud services, monitoring data across both internal and external networks. Depending on the deployment model—forward proxy, reverse proxy, API-based, or agent-based—a CASB can:
- Discover cloud usage across the organization
- Detect cloud based threats through behavioral analytics, machine learning, and anomaly detection
- Control access to sensitive data based on user, device, and location
- Enforce policies like DLP, encryption, and authentication
- Prevent data exfiltration from unmanaged devices
CASBs are widely used for securing collaboration tools like Microsoft 365, Google Workspace, Slack, Box, and Salesforce.
The Four Pillars of a CASB: Security Policy Enforcement
Visibility
Gain full insight into cloud app usage, users, and data movement across cloud environments.
Data Security
Apply DLP, encryption, tokenization, and rights management to protect sensitive information.
Threat Protection
Detect malware, account takeover, and behavioral anomalies with real-time alerts, leveraging threat intelligence to identify and prevent emerging threats.
Compliance
Ensure adherence to internal policies and external regulations across cloud apps.
CASB Solutions and Services
While CASBs are valuable, tA cloud access security broker (CASB) is an essential component of modern cloud security, providing organizations with the tools they need to safely adopt and manage both approved and unapproved cloud services. By acting as a central enforcement point, an access security broker CASB helps protect sensitive data, enforce security policies, and deliver robust threat protection.
CASB solutions offer a wide array of services, including data loss prevention (DLP), secure web gateways, and compliance management. These features enable organizations to safeguard sensitive data, prevent unauthorized access, and ensure that cloud usage aligns with regulatory requirements. CASB vendors provide flexible deployment options—such as API-based, proxy-based, or hybrid models—so organizations can choose the approach that best fits their needs and existing security infrastructure.
Integration is another key advantage of CASB solutions. They can work seamlessly with existing security tools like DLP systems, security information and event management (SIEM) platforms, and secure web gateways, enhancing the overall security posture. By leveraging a CASB solution, organizations can enforce security policies consistently across all cloud services, reduce the risk of data breaches, and maintain control over their cloud environments.
Implementing a CASB Solution
Successfully implementing a CASB solution starts with a clear understanding of your organization’s cloud services and security requirements. Begin by identifying which cloud services and applications are in use and determining the level of visibility and control needed to protect sensitive data. This will help define the scope of your CASB deployment and ensure that all critical cloud usage is covered.
Next, evaluate CASB vendors and their solutions, considering factors such as scalability, flexibility, and how well they integrate with your existing security infrastructure. It’s important to select a deployment model—API-based, proxy-based, or hybrid—that aligns with your organization’s architecture and compliance needs. Make sure the chosen CASB solution offers strong data security and threat protection capabilities, including real-time monitoring and alerting for security teams.
Throughout the implementation process, prioritize solutions that can adapt to your organization’s evolving cloud usage and regulatory landscape. By carefully assessing your needs and the capabilities of different CASB vendors, you can deploy a CASB solution that effectively secures your cloud services, protects sensitive data, and supports your overall security strategy.While CASBs are valuable, they weren’t designed to address some of the unique risks associated with modern SaaS environments. Key limitations include:
Best Practices for CASB Deployment
To maximize the effectiveness of your CASB solution, it’s important to follow best practices throughout the deployment process. Start with a comprehensive cloud discovery analysis to identify all cloud services and applications in use, including those that may be unsanctioned or unknown to IT. This step helps uncover potential risks and ensures that your security policies address the full scope of your organization’s cloud usage.
Develop a detailed security policy that specifies the required controls and protections for each cloud service and application. Configure your CASB solution to enforce these security policies using features such as access control, data loss prevention, and threat protection. Integrate the CASB with your existing security infrastructure—including firewalls and secure web gateways—to create a unified and layered defense.
Ongoing monitoring and reporting are crucial for maintaining visibility into cloud usage and ensuring that sensitive data remains protected. Regularly review CASB-generated reports and alerts to identify emerging threats and policy violations. By following these best practices, organizations can ensure that their CASB deployment delivers strong protection for cloud services and supports a secure, compliant cloud environment.
Limitations of CASBs in SaaS Security
While CASBs are valuable, they weren’t designed to address some of the unique risks associated with modern SaaS environments. Key limitations include:
Lack of Deep SaaS Configuration Insight
CASBs don’t monitor or manage SaaS tenant settings or security configurations.
No Visibility into SaaS-to-SaaS Integrations
OAuth-based third-party app connections and API tokens are often invisible to CASBs.
Deployment complexity
Proxy chaining and DLP policy creation can be time-consuming and error-prone.
Latency Issues
Proxy-based CASBs may introduce performance delays.
High False positives
Behavioral-based detections require constant tuning and can overwhelm security teams, and may struggle to accurately detect unauthorized user access.
Limited Coverage for Hybrid Cloud Environments
CASBs can face challenges in securing hybrid cloud environments, where the complexity of multi-cloud and on-premises integrations may limit their effectiveness.
Cloud Access Security Brokers and Governance
Cloud access security brokers (CASBs) are vital for establishing strong governance over cloud security. By providing a centralized platform to enforce security policies and controls, CASBs enable organizations to manage data security, monitor user activity, and deliver threat protection across all cloud services and applications. This unified approach helps organizations maintain compliance with regulatory standards such as GDPR, HIPAA, and PCI DSS, while also supporting internal governance requirements.
CASBs offer deep visibility into cloud usage, making it easier to identify and mitigate risks associated with shadow IT and unauthorized cloud services. With the ability to enforce security policies and monitor user activity, organizations can ensure that only authorized users have access to sensitive data and that all cloud usage aligns with established security protocols.
Furthermore, CASBs support the implementation of zero trust network access, granting access to cloud services based on user identity, device, and context rather than traditional network boundaries. This trust network access model adds an extra layer of protection for sensitive data and helps organizations maintain a strong security posture in the cloud. By leveraging a CASB solution, organizations can demonstrate a commitment to governance, maintain compliance, and ensure that their cloud environments are secure and well-managed.
CASB vs. SSPM (SaaS Security Posture Management)
SSPMs are increasingly adopted alongside or in place of CASBs to provide continuous configuration monitoring and risk remediation within SaaS apps.
Addressing Common SaaS Security Risks in Cloud Applications
- Misconfigurations: CASBs don’t detect excessive permissions, open file shares, or weak auth settings, which can put corporate data at risk.
- Configuration Drift: SSPMs track changes to SaaS settings over time—CASBs don’t, potentially impacting the organization's cloud usage and security posture.
- Shadow AI Risk: SSPMs can identify and restrict GenAI tools connected via SaaS-to-SaaS integrations, helping to secure the organization's cloud usage.
CASBs in the SASE/SSE World
As cloud security evolves, CASB features have been integrated into Secure Access Service Edge (SASE) and Security Service Edge (SSE) platforms—alongside Secure Web Gateway (SWG) and Zero Trust Network Access (ZTNA).
However, these platforms still lack deep configuration visibility. SSPMs complement CASB and SASE platforms by adding SaaS-native, configuration-level protection.
Frequently Asked Questions
What does a CASB do?
A CASB monitors and secures the use of cloud services, protecting sensitive data, managing access, and ensuring compliance.
Is a CASB only for SaaS?
No—CASBs secure SaaS, IaaS, and PaaS, but are most commonly associated with SaaS protection.
How is a CASB deployed?
Via API integrations, forward/reverse proxies, or endpoint agents. Each method has trade-offs in control, visibility, and complexity.
Is CASB the same as SASE?
No. CASB is a component of SASE/SSE architectures, which unify cloud and network security.
How does CASB compare to SSPM?
CASBs focus primarily on user access and data movement. SSPMs focus on securing SaaS app configurations, integrations, and usage patterns.
How do I choose a CASB vendor?
When selecting a CASB vendor, evaluate their integration capabilities with your existing cloud services, ensure their solution fits your specific use cases, and consider the vendor's reputation in the industry. It's also important to test the CASB vendor's functionalities through trials and conduct ongoing audits to confirm the solution continues to meet your organization's security requirements.
Secure Your SaaS with Valence
While CASBs offer foundational protection, they often miss the configuration risks and integration complexity of today’s SaaS environments.
Valence’s SaaS Security Platform combines:
- SaaS Security Posture Management (SSPM)
- SaaS Identity Threat Detection and Response (ITDR)
- One-click, guided, and automated remediation workflows
- Visibility into SaaS-to-SaaS integrations and identity risks
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