What is CASB (The Cloud Access Security Broker)?
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What is a CASB? The Cloud Access Security Broker explained
Companies are increasingly integrating cloud services into their daily business operations. However, this shift introduces new security challenges, as sensitive data can be at risk without proper security measures. This is where Cloud Access Security Brokers (CASB) come into play, acting as a security layer between users and cloud services. They monitor cloud traffic within an organization and enforce security policies.
What is the purpose of a Cloud Access Security Broker?
The abbreviation CASB stands for Cloud Access Security Broker and is by definition an on-premises or cloud-based network security service that acts as a control point between a company's users and third-party cloud services. It enforces security policies, monitors data traffic, and provides visibility into the use of cloud applications. By monitoring network traffic, this security application can detect unusual activities and enhance cloud security.
Why companies need a CASB architecture
Without a Cloud Access Security Broker solution, companies often lack the necessary control mechanisms to secure access to cloud services effectively, potentially leading to various security risks such as:
Data loss: Sensitive data can be inadvertently uploaded to unsecured cloud applications or shared with unauthorized individuals.
Malware infections: Unsecured clouds can serve as entry points for malware, potentially spreading across the corporate network.
Compliance violations: Without the ability to monitor and control cloud usage, companies may inadvertently violate legal or industry-specific compliance requirements, leading to hefty fines.
Undetected shadow IT: IT departments have no visibility into unauthorized application usage, increasing security vulnerabilities.
Hybrid work models are now widespread, amplifying these security concerns. Remote work requires access to company data from various locations and devices, increasing the risk of security breaches. Additionally, the ‘Bring Your Own Device’ (BYOD) approach allows employees to use personal devices for work, which often lack sufficient security protections and can act as entry points for cyber threats.
Given the growing reliance on cloud services and flexible work models, implementing a CASB is essential for businesses. The application provides the necessary visibility and control to secure cloud usage effectively, support employee productivity, and ensure compliance.
The four pillars of a Cloud Access Security Broker (CASB)
How do CASBs ensure secure cloud usage? The functionality of a Cloud Access Security Broker is, according to Gartner, an IT consulting firm, divided into four key pillars: Visibility, Threat Protection, Data Security, and Compliance Management.
Visibility
Shadow IT is one of the biggest challenges for companies, where employees use unauthorized cloud applications. A CASB analyzes and exposes the usage of such services, providing IT departments with a comprehensive overview of all cloud activities and applications — authorized or not. This helps to identify potential risks and take appropriate measures.
Threat Protection
The security tool protects corporate networks from threats such as malware, suspicious activities, and insider threats. By monitoring user behavior, CASBs can detect anomalies that may indicate compromised accounts or malicious insiders. For example, an unusual surge in data downloads by an employee may be flagged as suspicious, triggering automated security responses like access restrictions or alerts to the security team.
Data Security
A CASB implements data loss prevention (DLP) policies, encryption, and security enforcement mechanisms. By identifying and classifying sensitive data, they prevent unauthorized data sharing or downloads. For instance, a Cloud Access Security Broker can block the upload of confidential files to unsecured cloud services or ensure encryption before transfer.
Compliance Management
Businesses must comply with various regulatory and industry-specific data handling standards. CASBs help enforce compliance by ensuring adherence to these standards and monitoring compliance efforts. Features such as audit logs track all file activities for documentation and security compliance purposes.
By integrating these four pillars, Cloud Access Security Brokers provide a comprehensive security solution for cloud service usage, allowing companies to benefit from the cloud without compromising security or compliance. What are the benefits of a CASB in detail?
How businesses benefit from a Cloud Access Security Broker
By leveraging CASB’s four pillars — Visibility, Threat Protection, Data Security, and Compliance — companies minimize IT risks such as malware, data loss, and unauthorized cloud activity. Unlike traditional firewalls, the security tool provides additional security benefits:
Benefit | Description |
Enhanced visibility | CASBs offer clear insights into cloud application usage and user activities, helping companies identify risks and implement appropriate security measures. |
Protection of sensitive data | Cloud Access Security Brokers provide advanced security mechanisms to block both external and internal threats. |
Support for compliance policies | Companies are subject to various regulations that govern data handling. A broker offers features like audit logs to document file activities, essential for proving compliance with regulations. |
Integration into security frameworks | CASBs integrate seamlessly with architectures such as Zero Trust Network Access (ZTNA) and Secure Access Service Edge (SASE). ZTNA inherently distrusts all users and devices, while SASE combines networking and security functions in a cloud-based framework. |
A CASB ensures secure and efficient cloud usage by providing extensive control over applications. But how does a Cloud Access Security Broker function? That’s what businesses must understand in order to maximize its benefits.
How does a CASB work?
The security application sits between users and cloud applications, monitoring all cloud-related activities with various control mechanisms. In modern enterprises, data syncs between the cloud and on-premises servers, constantly transferring information. The Cloud Access Security Broker architecture enforces multiple security measures on that level:
Malware Protection: Detects and blocks malicious software attempting to steal data or infect IT systems.
Encryption: Encrypts data both in storage and during transmission to prevent unauthorized access.
Identity Management: Enforces authentication methods to ensure that only authorized users access sensitive cloud resources.
Monitoring & Control: Provides administrators with insights into who is sharing or accessing which data, preventing uncontrolled data leaks.
When implementing these mechanisms, an CASB tool operates in three key steps. The process begins with identifying all cloud applications, followed by classifying and assessing them based on risk levels, and finally by implementing specific security measures.
CASB: Important use cases and examples
Businesses increasingly rely on cloud services. Cloud Access Security Brokers or CASBs play a crucial role in safeguarding SaaS applications, cloud storage, remote work, collaboration platforms, and cybersecurity from cyber threats. The most common Cloud Access Security examples are the following:
Control over SaaS applications
Companies frequently use SaaS tools, ranging from CRM systems and office services to accounting software. A CASB monitors access to these applications and enforces security controls. For example, it prevents sensitive data from being sent in emails or documents without encryption. Additionally, it provides insights into user activities, including which data is shared and by whom.
Protection of cloud storage and collaboration platforms
In cloud-based storage and collaboration platforms, Cloud Access Security Brokers monitor data traffic and prevent unauthorized access. For instance, the system can block the upload of sensitive information to unsecured clouds or ensure that files are shared only with authorized users, therefore reducing the risk of data leaks significantly.
Enforcing security controls for mobile and remote users
With the CASB architecture, companies can implement security measures regardless of an employee’s location or device. For example, access to specific cloud services from unsecured networks can be restricted, or additional authentication measures can be required. This ensures that corporate data remains protected even outside the company network.
Protection against account compromise and phishing attacks
Phishing scams and compromised user accounts pose significant security risks. A Cloud Access Security Broker detects unusual activity, such as access to cloud services from unknown locations or devices, and takes appropriate countermeasures. The product also supports multifactor authentication (MFA) to enhance user account security.
By controlling SaaS applications, securing cloud storage, enforcing security policies for mobile users, and preventing account compromise, CASBs help businesses securely manage their data in the cloud.
Choosing the right CASB: What companies should consider
The implementation of a Cloud Access Security Broker (CASB) is essential for companies using cloud applications. To maximize protection, companies should evaluate available solutions based on the following criteria:
Visibility: An effective CASB should provide an overview of all cloud applications in use, enabling IT departments to identify unauthorized applications and minimize security risks.
Threat protection: The service should be capable of detecting malicious activities and compromise attempts. Additionally, it should identify malware risks, prevent unauthorized access to infrastructure and data, and notify administrators of security incidents.
Compliance functions: A CASB should ensure compliance with legal and industry-specific regulations. Key features include Data Loss Prevention (DLP), the ability to scan and identify sensitive data, conduct risk assessments, and manage access across all applications and data types.
Additionally, Cloud Access Security Brokers should be compatible with existing security systems, such as Identity and Access Management (IAM) and Security Information and Event Management (SIEM). IAM manages digital identities and access rights within a company. SIEM collects, analyzes, and evaluates log data (e.g., logins, system crashes, configuration changes) from various IT systems, helping to detect security threats at an early stage. That kind of compatibility provides consistent enforcement of security policies and simplifies management.
For a successful implementation, the following approach is recommended:
Needs Analysis: Before selecting a CASB, the company needs to identify its specific requirements and use cases, which helps executives and IT departments find the optimal solution for their business objectives.
Scalability: The chosen Cloud Access Security Broker should ideally grow with the company and adapt flexibly to future demands.
Awareness: Employees should be trained in using the new solution to assure its effective implementation and best security practices.
Monitoring: After implementation, it is crucial to regularly assess the effectiveness of the CASB and make necessary adjustments if required.
By following these best practices, businesses can enhance their cloud security while complying with regulatory requirements.
The two main architectures of a Cloud Access Security Broker
A CASB tool can be implemented in two different ways: API-based or Proxy-based. What are the key differences between these two approaches?
With the API-based approach, the broker communicates with the cloud via an Application Programming Interface (API). It operates outside the direct data exchange between users and cloud applications, only receiving information about user activity through the API. This approach does not negatively impact network performance and is compatible with a wide range of applications. However, real-time monitoring and immediate blocking of activities are generally not possible due to the API's limitations.
The Proxy-based approach, on the other hand, places the CASB directly as a gateway between users and cloud services. It is integrated into the data stream, meaning all network traffic passes through the service, allowing it to monitor, control, and enforce security policies in real time. This approach can immediately detect and block suspicious activity, but it comes with potential drawbacks such as higher latency and a more complex implementation.
Conclusion: Cloud Access Security Broker as the key for safe cloud usage
A Cloud Access Security Broker or CASB is crucial for businesses using cloud services, enhancing cloud security significantly through strategic implementation. The application provides threat protection, control over cloud applications, and compliance enforcement. Without them, organizations risk data breaches, compliance violations, and shadow IT vulnerabilities.
To ensure long-term security, businesses should assess their security needs, choose the right CASB, and integrate it into their IT security architecture. With proper training and regular evaluations, companies can maintain high security standards in the evolving digital landscape.
Frequently Asked Questions about CASB (Cloud Access Security Broker)
What does CASB stand for?
CASB is the abbreviation for Cloud Access Security Broker.
What is CASB used for?
It is used to secure cloud applications by monitoring and controlling data flow, preventing security threats, and ensuring compliance.
What does a CASB do?
A Cloud Access Security Broker acts as a security layer between users and cloud applications, enforcing security policies, monitoring data traffic, and ensuring compliance.
What are the 4 pillars of CASB?
The four pillars are Visibility, Threat Protection, Data Security, and Compliance Management.
What is the difference between a firewall and a CASB?
A firewall protects a network from external threats, while a CASB secures cloud-based applications by monitoring access, enforcing policies, and preventing data leaks.
Is CASB the same as SASE?
No, Cloud Access Security Broker is a component of SASE (Secure Access Service Edge). It integrates multiple security solutions, including CASB, to provide a holistic cloud security framework.
What is the difference between DLP and CASB?
DLP (Data Loss Prevention) focuses on preventing data leaks, while CASB provides broader security, including visibility, threat protection, compliance, and data security.