A Cloud Access Security Broker (CASB) is a security policy enforcement point placed either on-premises or between cloud users and providers, aiming to secure data, ensure compliance, and monitor cloud usage. CASBs protect against data leakage and unauthorized access to cloud apps, including Software-as-a-Service (SaaS) applications, often through features like data loss prevention (DLP), access control, and threat protection.
How Does a CASB Work?
A CASB functions as an intermediary between users and cloud-based applications. . CASBs can be implemented in a few different ways, such as via proxy or API integration, to inspect traffic flowing between on-premises users and cloud resources. By monitoring data transfers, CASBs allow IT / security teams to track and control cloud activities, prevent data leaks, enforce compliance, and detect shadow IT.
What are the Advantages of Using a CASB to Secure SaaS?
CASBs are increasingly becoming essential for organizations that are adopting cloud services, as they offer a range of benefits that can help to secure SaaS and improve overall security posture.
- Shadow IT / SaaS discovery: One of the primary benefits of using a CASB is that it provides organizations with visibility into SaaS usage. This includes identifying which cloud services are being used, by whom, and for what purpose. This information can help organizations to better understand and manage their cloud environments, provide visibility into shadow IT by identifying unapproved applications, monitor user activities within these applications and identify potential security risks.
- Access control: CASBs monitor and restrict access based on policies to prevent unauthorized access to cloud data.
- Data loss prevention: DLP is a core feature of most CASBs. Classifying data is necessary to determine risk and how policies should be applied, so most CASB vendors prioritized building data discovery and classification early on. Then, CASBs can control or limit data movement and prevent leakage. This can help organizations to ensure that sensitive data is protected, and that users are only able to access the resources that they need.
- Managing sanctioned vs unsanctioned SaaS use: One of the benefits of in-line CASB architectures (mostly forward proxies), is the ability to manage both sanctioned and ‘shadow IT’ (unsanctioned) SaaS use alike. API-based and reverse proxy CASB architectures can only be used with sanctioned SaaS, as they require access to the target application to work.
- Secure SaaS usage: This includes the ability to enforce security policies and access controls, and monitor and manage user activity. For example, CASBs can be used to enforce or add certain features, like multi-factor authentication and data encryption.
- Compliance: CASBs can help organizations to comply with regulations and industry standards, such as GDPR, HIPAA, or NIST. CASBs can be configured to meet specific compliance requirements, such as those related to data privacy and security.Security teams can use the CASB to apply data protection policies and alert administrators to any non-compliant activities. This can help organizations to avoid costly fines and penalties for non-compliance.
- Detection & Response: CASBs can provide threat detection and incident response capabilities. This can help organizations to detect and respond to potential security threats, such as impossible travel or mass download of data, more quickly and effectively, regardless of whether threats come from internal users, or external entities.
What Are the Four Pillars of CASB?
The four pillars of CASB are essential functions CASBs claim to provide that support an organization's cloud security strategy:
Visibility
This is the foundation of CASB, offering insights into who accesses which applications and data. By identifying all cloud services in use, organizations can address shadow IT and ensure only authorized users access specific resources.
Data Security
CASBs enforce data protection policies, including encryption, tokenization, and access controls, to secure sensitive data in transit and at rest within cloud applications.
Threat Protection
CASBs provide advanced security features like anomaly detection and malware prevention, which can help to prevent data breaches and protect against sophisticated cyber threats.
Compliance
CASBs enable organizations to meet regulatory and internal compliance requirements by implementing consistent security policies across cloud applications and monitoring for compliance violations.
Together, these pillars enable organizations to safely leverage cloud services while maintaining visibility, protection, and control.
While CASBs were once the primary solution for cloud security, however, their effectiveness across some of these use cases is increasingly debated. CASBs have faced challenges in addressing some of the unique needs of modern, complex SaaS ecosystems and their particular risks. Over the past few years, many organizations have adopted complementary or alternative solutions to close these gaps. For example, just as we’ve seen massive adoption of Cloud Security Posture Management (CSPM) tools, focused on securing cloud infrastructure environments, we’re also seeing increasing interest in SaaS Security Posture Management (SSPM) tools, which specifically target the configuration and security needs of SaaS applications. As a result, SSPMs are often implemented alongside or in place of CASBs to provide more nuanced visibility, control, and protection in SaaS environments. Below, we’ll explore the specific limitations of CASBs when it comes to securing SaaS applications.
What Are The Limitations of CASB in SaaS Environments?
While CASBs can provide many benefits, such as visibility and control over cloud usage, they also have some limitations:
SaaS misconfigurations blindspot
SaaS applications have evolved to become complex platforms, allowing customers and business users to customize many configurations, including security configurations. The shared responsibility model requires SaaS customers to manage their own tenants, creating a complex setup that CASBs do not analyze. According to our 2024 State of SaaS Security Report, 48% of security leaders identified “tracking changes in functionalities and risks in each SaaS application” as a key challenge. CASBs typically don’t provide deep insights into the configuration settings, nor detect configuration drift, within individual SaaS applications.
SaaS-to-SaaS integration blind spots
Most organizations have hundreds if not thousands of integrations between SaaS applications using OAuth apps, API tokens and service accounts. This SaaS-to-SaaS communication is ignored by most CASBs, so that many third-party integrations are unseen and uncontrolled by the CASB, which can lead to unchecked risk.
Deployment complexity
Implementing and managing a CASB can be complex and time-consuming due to the effort required to build DLP policies. Unless there is integration with on-Prem DLP policies need to be created from scratch which is time consuming and requires expertise. In addition, proxy chaining can cause deployment challenges.
Latency
Proxy-based CASBs can add latency to the connection, which can affect the performance of cloud applications.
False positives
CASBs can generate false positives which can lead to false alerts, making it harder to identify real security issues. Behavioral-based detections are notoriously tricky, requiring constant tuning to cut down on unnecessary alerts. A certain amount of false positives is inevitable.
It's important to evaluate your organization's specific needs and requirements when considering using a CASB to secure SaaS applications, and to understand the limitations of the technology.
CASB vs. SSPM
Comparing CASBs and SaaS Security Posture Management (SSPM) solutions helps highlight each tool’s unique focus:
SSPMs provide proactive management of SaaS-specific security settings, reducing misconfigurations and enhancing SaaS security posture.
Addressing Common SaaS Risks Beyond CASB
- Common misconfigurations: CASBs may miss critical SaaS configuration issues, like excessive permissions or weak authentication due to unenforced MFA/SSO. 43% of security executives flagged the “complexity of SaaS configurations” as a top barrier, which CASBs typically lack the depth to manage effectively
- Configuration drift: SSPMs monitor for configuration drift as SaaS app settings and usage update, while CASBs are often limited to broader data policies
- Shadow AI usage: While CASBs can indeed help discover SaaS applications. SSPMs excel at identifying risks from shadow AI tools, which often connect through SaaS-to-SaaS integrations, and can help monitor, configure, and restrict these connections to mitigate data security and privacy risks
How do CASBs integrate with SASE?
As security technology advances, CASB capabilities have largely been integrated into Secure Access Services Edge (SASE) and Security Service Edge (SSE) platforms. These platforms unify CASB functionalities with Zero Trust Network Access (ZTNA) and Secure Web Gateways (SWG) in one solution, centralizing control over cloud and network security. However, these solutions still lack the necessary depth of protections against risks from SaaS complexities like misconfigurations, external data sharing, and SaaS-to-SaaS integrations. SSPMs complement CASB or SASE/SSE platforms by adding configuration-focused protection at the application level, addressing the unique security needs of modern SaaS environments.
While CASBs have been widely used (52% of organizations), SSPMs are close behind at 48%, reflecting a shift toward SaaS-specific, configuration management tools.
Frequently Asked Questions
How do CASBs compare with SASE/SSE platforms?
SASE and SSE platforms have integrated CASB functionality alongside network security controls, while SSPMs extend this by managing configuration security within SaaS apps.
What challenges come with CASB?
Deployment complexity, limited SaaS application support, proxy dependency, and limited visibility into deep SaaS configurations are notable challenges.
What is CASB's deployment method?
CASBs can be deployed as agents, in-line proxies, out-of-band API integrations, or a mix of all three, each impacting functionality and deployment complexity differently.
Is CASB only for SaaS?
No, CASBs are typically used to secure not only SaaS but also Infrastructure-as-a-Service (IaaS) and Platform-as-a-Service (PaaS) environments, providing data security, access management, and threat protection across cloud environments.
For organizations with significant SaaS ecosystems, combining CASBs with SSPMs provides a robust security framework. CASBs manage broader cloud access and data security, while SSPMs ensure that SaaS configurations remain secure and compliant with industry standards.
Secure Your SaaS with Valence
Valence’s SaaS Security platform delivers SaaS Security Posture Management (SSPM) capabilities that help organizations uncover security gaps, manage SaaS configuration risks, and detect threats across applications. With advanced risk remediation capabilities—offering guided remediation, ticketing, one-click remediation, automated workflows and business user collaboration—Valence provides comprehensive visibility and control over SaaS security. Furthermore, Valence’s SaaS Identity Threat Detection and Response (ITDR) capabilities help security teams detect, investigate, and respond to live threats.
Take the first step toward securing your SaaS ecosystem—schedule a SaaS risk assessment with Valence today.
