What is a Cloud Access Security Broker (CASB)

What is a CASB?

Cloud Access Security Brokers (CASB) are tools that act as a proxy between an organization’s users and SaaS properties, delivering security and policy enforcement for public SaaS applications, such as Dropbox or Salesforce. A CASB helps enforce an organization’s security policies and protects against data breaches and cyberattacks.

Typical capabilities of a CASB are:

Monitor activity: a CASB monitors user activity in the cloud to potentially identify suspicious activity.
Enforce security policies: a CASB can ensure that users follow organizational rules for cloud consumption, (mostly for SaaS properties and usually not for IaaS/PaaS and the general public web) such as requiring strong passwords or encrypting sensitive data.
Prevent data loss: a CASB can help prevent accidental or malicious data leaks by blocking users from sharing sensitive information outside of the organization.
Ensure compliance: a CASB can help achieve compliance with industry regulations that concern data security.

CASB capabilities increase in importance as organizations grow more reliant on cloud services. CASBs can help organizations embrace SaaS and the cloud while maintaining control over data and staying compliant with regulations. As hybrid work becomes the norm, it’s important to consider whether on-premises CASB’s should evolve to cloud-driven CASB services that work alongside browser security capabilities to reduce risk while being sure to address remote workers using public SaaS services.

How do organizational users access a CASB?

Organizational users typically wouldn't directly access a CASB because it operates behind the scenes, typically integrated with an organization's existing security infrastructure and access control mechanisms. Users interact with the resources they normally access (cloud applications, webmail, etc.), and the CASB works in the background to enforce security policies.
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Here's a typical breakdown of how a user gains access to cloud resources is mediated by a CASB:

User Requests Access: A user tries to access a SaaS application or cloud storage.
Authentication: The user logs in using their organizational credentials (typically through a single sign-on (SSO) system).
- SSO Integration: The SSO system communicates with the CASB, providing user identity and access request details.
CASB Policy Enforcement: The CASB checks the user's identity, device, and the requested resource against predefined security policies.
Conditional Access: Based on the policy evaluation, the CASB might:
- Grant Access: with sufficient policy verifications the CASB grants access to the requested resource.
- Step-up Authentication: The CASB might require additional authentication factors for high-risk scenarios.
- Block Access: If the request violates a policy (e.g., unauthorized device), the CASB blocks access and the user might see an error message.

In essence, a CASB acts as a security checkpoint between users and cloud resources. Users don't need a separate login or interface for the CASB. Their familiar access methods (SSO, login credentials) are enhanced with the additional security layer provided by the CASB.

What are the four top CASB features?

The four top general features for a Cloud Access Security Broker (CASB) are visibility and control, data security and compliance, threat protection, and identity and access management (IAM) integration.

Visibility and Control: A CASB should provide comprehensive visibility into all cloud services being used by the organization, including sanctioned and unsanctioned (shadow IT) applications.
Data Security and Compliance: The CASB should have functionalities to protect sensitive data in the cloud. This includes data encryption, data loss prevention (DLP) controls, and the ability to monitor and audit data access activities.
Threat Protection: A CASB should offer protection against various cloud-based threats like malware, phishing attacks, and unauthorized access attempts. This might involve features like threat detection and prevention capabilities, anomaly detection, and integration with threat intelligence feeds.
Identity and Access Management (IAM) Integration: The CASB should integrate seamlessly with existing IAM systems to leverage established user identities and access controls. This streamlines user access management and ensures consistent security policies across cloud and on-premises resources.

Can a CASB secure access to internal web applications?

CASBs and internal web applications have a complex relationship.
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Traditionally, CASBs were designed primarily for securing cloud applications. However, the line between cloud and on-premises applications has blurred significantly over time.
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Some modern CASBs can provide some a modest level of security for internal web applications, but their effectiveness is often limited compared to traditional security solutions designed specifically for on-premises environments.

How CASBs Can Secure Internal Web Applications

Visibility: Some CASBs can offer limited visibility into internal web application usage patterns, helping identify potential risks and anomalies.
Data Loss Prevention (DLP): Some CASBs can protect sensitive data within internal applications by implementing DLP policies.
Threat Protection: Certain advanced CASBs might offer some level of threat protection for internal web applications, such as malware scanning or intrusion prevention.

Limitations of CASBs for Internal Web Applications

Focus on Cloud: CASBs are primarily designed for cloud environments, and their capabilities for on-premises applications are often limited.
Network Segmentation: CASBs typically rely on network segmentation to identify internal applications, which might not always be accurate or effective.
Performance Impact: Deploying a CASB for internal traffic can introduce latency and impact user experience.

While CASBs can provide some benefits for securing some internal web applications, they are not typically the primary solution. A combination of CASBs and traditional on-premises security controls often offers the most comprehensive protection.

Learn how Menlo secures your internal web apps

How does a VPN user reach web applications through a CASB?

Typically, a VPN user accesses web applications through a CASB by establishing a secure connection with the CASB before accessing the application.
Here's a breakdown of the process:

VPN Connection: The user establishes a VPN connection to the corporate network. This creates a secure tunnel between the user's device and the organization's infrastructure. Regarding SaaS applications, this is known as backhauling all traffic rather than permitted traffic to go directly to cloud applications.
CASB Integration: The CASB is integrated into the corporate network, acting as a security gateway for all outbound traffic.
Web Application Access: When the user attempts to access a web application, the traffic passes through the VPN tunnel and then reaches the CASB.
CASB Inspection: The CASB inspects the traffic for security threats, enforces data loss prevention policies, and verifies user identity and authorization.
Application Access: If the CASB clears the traffic, it allows the user to access the web application.

Key Points:

The VPN provides a secure connection to the corporate network.
The CASB acts as an additional layer of security on top of the VPN, inspecting traffic and enforcing policies.
This combined approach enhances security by providing multiple layers of protection.

Important Considerations:

While this approach is common, some organizations might deploy CASBs in a forward proxy mode, where all traffic is routed through the CASB regardless of whether a VPN is used.
The effectiveness of this combination depends on the configuration and capabilities of both the VPN and CASB.
Many modern organizations implement VPN’s with split tunnels, such that access to the cloud is direct from the user’s device. This offers significant performance benefits and reduced wasted network resources, but tends to take the CASB out of the path between users and SaaS applications.

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What are the main disadvantages of using CASBs?

While CASBs can offer significant benefits in securing many cloud applications, they also come with certain limitations.

1. Complexity and Management Overhead:

Configuration challenges: Implementing and configuring a CASB can be complex, requiring specialized expertise.
Policy management: Maintaining and updating security policies across multiple cloud applications can be time-consuming.
False positives: Overly restrictive policies can lead to false positives, impacting user productivity.

2. Performance Impact:

Increased latency: Introducing a CASB into the traffic flow can introduce latency, affecting application performance.
User experience: Performance degradation can impact user satisfaction and productivity.

3. Cost:

Licensing fees: CASB solutions can be expensive, especially for large organizations with numerous cloud applications.
Ongoing maintenance: Maintaining and updating the CASB requires ongoing investment in resources and expertise.

4. Limited Visibility into Shadow IT:

Unmanaged applications: CASBs might struggle to detect and control shadow IT applications, leaving security gaps.
Data exfiltration risks: Shadow IT applications can increase the risk of data leakage.

5. Dependency on Cloud Provider APIs:

API limitations: CASBs rely on cloud provider APIs, which can limit their functionality and effectiveness.
Changes in API behavior: Updates to cloud provider APIs can impact CASB performance and require adjustments.

6. Evolving Threat Landscape:

Staying updated: Keeping up with the latest threats and vulnerabilities requires constant updates and adjustments to CASB policies.

How does the rapid evolution of web languages and features reduce the effectiveness of a CASB?

The rapid evolution of web languages and features poses significant challenges to the overall effectiveness of Cloud Access Security Brokers (CASBs).

Here's how these changes impact CASBs:

1. Dynamic Content and Obfuscation:

Complex rendering: Modern websites heavily rely on client-side scripting and dynamic content generation, making it difficult for CASBs to accurately inspect and analyze web traffic.
Evasion techniques: Malicious actors can exploit these complexities to obfuscate malicious content and bypass CASB controls.

2. WebAssembly (WASM):

Performance and security trade-off: WASM's ability to run code at near-native speed can complicate security analysis.
Potential for abuse: Malicious actors might leverage WASM to deliver malware or exploit vulnerabilities.

3. Serverless Architectures and APIs:

Shifting attack surface: The increasing use of serverless functions and APIs expands the potential attack surface, making it harder for CASBs to protect against threats.
API abuse: Protecting APIs from unauthorized access and abuse is a complex challenge for CASBs.

4. Real-Time Communication:

Encrypted traffic: Technologies like WebRTC often use encrypted communication, making it difficult for CASBs to inspect traffic without compromising user privacy.
Peer-to-peer connections: Peer-to-peer file sharing and collaboration can bypass traditional security controls.

5. AI and Machine Learning Integration:

Adaptive threats: Malicious actors are increasingly using AI to create sophisticated attacks that can evade traditional security measures.
Staying ahead: CASBs need to evolve their threat detection capabilities to keep pace with AI-driven attacks.

In essence, the dynamic nature of web technologies requires CASBs to constantly adapt and evolve to maintain their effectiveness. This necessitates a combination of advanced threat detection techniques, machine learning, and continuous updates to stay ahead of emerging threats.

How does a CASB use SaaS provider APIs?

A Cloud Access Security Broker (CASB) leverages SaaS provider APIs to gain visibility and control over organizational use of cloud applications. By integrating with these APIs, CASBs can monitor and manage data, users, and applications within the cloud environment.

Here's a breakdown of how CASBs utilize SaaS provider APIs:

Key Use Cases:

Data Discovery and Classification:

CASBs can access metadata and content information to identify sensitive data.
Data classification rules can be applied to categorize data based on sensitivity levels.

User and Access Management:

CASBs can retrieve user information, roles, and permissions from the SaaS provider's API.
This enables enforcement of access controls and anomaly detection.

Threat Detection and Prevention:

CASBs can use API data to detect malicious activities, such as suspicious login attempts or data exfiltration.
Real-time threat intelligence can be integrated to enhance protection.

Compliance and Auditing:

CASBs can collect audit logs and reports through APIs to ensure compliance with industry regulations.
Data retention policies can be enforced based on compliance requirements.

Shadow IT Detection:

CASBs can discover unauthorized SaaS applications by analyzing API data and user behavior.

Benefits of API-Based CASBs:

Enhanced visibility: Deeper insights into cloud application usage and data.
Improved performance: Reduced latency compared to proxy-based CASBs.
Scalability: Ability to handle increased workloads and growing number of users.
Reduced security footprint: Lower impact on network infrastructure.

Challenges:

API limitations: Not all SaaS providers offer comprehensive APIs, limiting CASB capabilities.
API rate limits: Excessive API calls can impact performance and incur additional costs.
API changes: Updates to SaaS provider APIs can require modifications to the CASB.

By effectively utilizing SaaS provider APIs, CASBs can significantly enhance their ability to protect sensitive data, prevent unauthorized access, and ensure compliance with organizational policies.

What are the main internal components of a CASB?

A Cloud Access Security Broker (CASB) consists of several key components working together to provide comprehensive cloud security. These components include the Data Discovery and Classification Engine, Threat Detection and Prevention Module, Policy Engine, API Integration Module, User and Entity Behavior Analytics (UEBA) Engine, Reporting and Analytics Module, Orchestration and Automation Engine, and Cloud Security Posture Management (CSPM) Module.

1. Data Discovery and Classification Engine:

Identifies sensitive data across various cloud platforms.
Classifies data based on sensitivity levels, regulatory requirements, or business value.
Enables targeted protection and data loss prevention policies.

2. Threat Detection and Prevention Module:

Leverages advanced threat detection techniques such as behavioral analysis, machine learning, and sandboxing.
Protects against malware, ransomware, and other cyber threats.
Detects anomalies and suspicious activities.

3. Policy Engine:

Defines and enforces security policies for cloud applications and data access.
Includes access controls, data loss prevention rules, and compliance regulations.

4. API Integration Module:

Connects to various cloud service provider APIs to collect data and enforce policies.
Enables seamless integration with different cloud platforms.

5. User and Entity Behavior Analytics (UEBA) Engine:

Analyzes user and entity behavior to detect anomalies and potential threats.
Identifies suspicious activities that might indicate insider threats or account compromise.

6. Reporting and Analytics Module:

Collects and analyzes security data to generate reports and insights.
Provides visibility into cloud usage, security posture, and compliance status.

7. Orchestration and Automation Engine:

Automates security tasks and workflows.
Integrates with other security tools and systems for enhanced protection.

8. Cloud Security Posture Management (CSPM) Module:

Assesses the security posture of cloud environments.
Identifies misconfigurations and vulnerabilities.
Provides recommendations for remediation.

These components work together to provide a comprehensive CASB solution that protects sensitive data, prevents unauthorized access, and ensures compliance with industry regulations.

Would you like to delve deeper into a specific component?