AVG Signal Blog Security Internet What Is a Cloud Access Security Broker?

Written by Deepan Ghimiray
Published on July 14, 2022

What is a cloud access security broker?

A cloud access security broker (CASB) acts as an intermediary between a company’s hardware or computing infrastructure and its cloud service providers. A cloud access security broker establishes and enforces security protocols between networks, cloud service providers, and end users, ensuring security standards when employees remotely access resources over the internet.

This article contains :

    Data theft and other cybercrimes can be devastating for a business. As organizations increasingly rely on cloud services, CASBs have become an essential component of enterprise security. Although cloud service providers also maintain their own security infrastructure, a CASB fills in the gaps, adding extra layers of protection to guard against vulnerabilities.

    Like with many cyber security terms, it’s easy to get bogged down in complex technical jargon, but the CASB definition is actually fairly simple. A cloud access security broker acts like a lookout tower, overseeing data exchanges and enforcing company data policies. Along with staying on guard against external hacking attempts, organizations need to be vigilant about monitoring internal unsanctioned cloud usage, and they use CASBs to help protect their networks.

    A cloud access security broker sits between end users and the cloud.A CASB sits between end users and the services they access in the cloud.

    The story behind CASBs

    Before cloud computing, businesses could focus on managing data in one place. This “walled garden” security environment made it easy to control access to network-based data. But the introduction of cloud services changed this security dynamic.

    The rise of “bring your own device” (BYOD) policies in offices made it difficult to track device usage and company data. Cloud access also allowed employees to use services without the knowledge or approval of the IT department, which put sensitive data at risk.

    Cloud access security brokers emerged to address this vulnerability, and the CASB acronym was born. Using a CASB helped IT professionals monitor the use of their devices, data, and services, as well as restrict unsanctioned employee cloud usage.

    And as more and more organizations have turned to cloud solutions to store ever larger volumes of sensitive data, CASBs have become even more critical.

    From identity theft to hijacking webcams, hackers are constantly trying to exploit security vulnerabilities, and cloud computing presents new opportunities and potential backdoors to spread malware or steal data. That’s why specialized browsers for security and privacy, VPNs, and CASBs are now considered essential enterprise security solutions.

    The evolution of CASBs

    Since they were first introduced, cloud access security brokers have evolved to adapt to changing security environments. In particular, the growth of Software as a Service (SaaS) companies have presented new security vulnerabilities.

    SaaS tools like Slack (a workplace messaging tool) are now integral to day-to-day business operations. And though incredibly useful, they also heighten the risk of unsanctioned use of cloud-based services and of the exposure of sensitive corporate data. Seeing their private information surface in a dark web scan is every company’s worst nightmare, so cloud access security brokers have evolved to address data theft concerns in cloud storage and usage.

    CASBs were once used as an all-purpose security solution, but today they are integrated with other network security control points. This more collaborative approach to cloud security results in streamlined deployment, consistency in management, and improved security effectiveness.

    The four pillars of CASB

    Effective cloud access security brokerage is based on four essential components. These parts work in harmony to support a powerful cloud security solution.

    Let’s take a closer look at the four pillars of CASBs:

    Threat protection

    Malware and other online threats can easily be introduced and spread through a company using cloud services. Effective CASB solutions provide real-time threat protection alongside malware and virus removal tools. They can scan and target threats across internal and external networks, as well as block unauthorized access to a company's cloud services and data.


    Whether voluntary or legal regulations, compliance standards are vital for maintaining the integrity and reputation of an organization. Unsanctioned use of cloud tools makes it all too easy for data to be mishandled. CASB tools help enforce compliance standards in cloud services by enforcing data policies.

    Data security

    Cloud access security brokers provide more comprehensive data protection than email security and other, more focused tools. CASBs detect sensitive data traffic to or from the cloud — automatically alerting IT to any suspected violations. A CASB also provides threat observation research, helping to identify and prevent malicious activity before it escalates.


    Companies can find it difficult to keep track of sensitive data in the cloud, increasing the risk of data leakage — especially since most cloud services lack auditing and logging functions. CASBs enhance data visibility and management by tracking and highlighting data points and transfers.

    The four pillars of cloud access security brokers.CASBs rely on four pillars of security: threat protection, compliance, data security, and visibility.

    How CASBs work

    The main functions of a CASB are to control cloud usage, protect data, and prevent malware threats. To do this, CASBs follow a specific process involving inventory and categorization of cloud-usage, as well as proactive data protection.

    Here’s how CASB software works in practice:

    1. Discovery: CASBs use auto-discovery tools to take inventory of all cloud-service use within a company — including both sanctioned and unsanctioned usage.

    2. Classification: The CASB then assesses the risk level of each cloud service being used. It will determine the function of the tool, analyze the data exchanged, and assess how and where the data is shared.

    3. Remediation: Cloud access security brokers use the information gathered during discovery and classification to create policies for company data, set user access rules, and respond to violations.

    The benefits of CASBs

    For large businesses handling huge amounts of customer data and sensitive financial information, relying on basic cybersecurity tools for getting rid of viruses or malware and using a VPN doesn’t cut it against the most dangerous hackers today. CASBs provide specific solutions to the security vulnerabilities of businesses that use cloud-based services.

    Here are the main benefits of CASBs:

    • Cloud governance and risk management

    • Corporate data-loss prevention

    • Collaboration and sharing control

    • Threat prevention and malware detection

    • Data encryption and key management

    • Access control

    How to choose the right CASB

    The right CASB depends on your business and its unique security environment. The first step is understanding what kind of cloud services you use and how you use them. From there, you can find a reliable CASB that addresses your specific business needs and essential security requirements.

    Categories of cloud computing services:

    There are three main categories of cloud computing services:

    • Infrastructure as a Service (IaaS):

      IaaS provides virtual computing resources over the internet. These services deliver fundamental computer, network, and storage resources on demand.

      Examples: Microsoft Azure, Amazon Web Services, Google Cloud Infrastructure.

    • Software as a Service (SaaS):

      SaaS delivers online applications as a service. Rather than installing and maintaining software, these services are accessed via the internet, removing the need for complex software and hardware management.

      Examples: Microsoft Office 365, Slack, Dropbox.

    • Platform as a Service (PaaS):

      PaaS is a complete development and deployment environment in the cloud. They include resources that enable you to deliver everything from simple, cloud-based apps to sophisticated, cloud-enabled enterprise applications.

    Examples: SAP Cloud, Google App engine, Heroku.

    Choosing your CASB

    Once you understand which cloud services your company uses, you can start considering which CASB suits your business operations and other specific needs.

    Here are three things to keep in mind when choosing a CASB:

    What do I need from a CASB?

    Consider the cloud computing services your business employs and identify what you are looking for from a CASB. Consult internal stakeholders and seek input from cybersecurity analysts or business consultants to help focus your needs.

    Will my CASB adapt to changes?

    Cybersecurity environments constantly change as technology progresses — especially with cloud usage. Well-known CASBs like Gartner and Bitglass keep abreast of changes by updating cloud compliance and security policies.

    Will my CASB protect IaaS?

    Although SaaS protection is common, comprehensive enterprise security protects IaaS environments too. Consider a CASB that not only protects activity and configurations in IaaS, but also defends customers through threat protection and activity monitoring.

    Stay protected online with strong security software

    While the cloud has many benefits, there’s always a risk that critical files could be corrupted and sensitive data exposed — even with the added protection of a CASB. That’s why there’s no substitute for comprehensive antivirus software when it comes to taking control of your privacy and security.

    AVG AntiVirus FREE is powered by an award-winning threat-detection engine, providing six layers of security against viruses, spyware, and other malware threats. And with anti-phishing technology, an impenetrable firewall, and real-time updates to combat the latest hacking tools, you’ll remain protected against even the latest cyberthreats.

    Get real-time security for your iPhone with AVG Mobile Security

    Free install

    Get real-time security for your phone with AVG AntiVirus

    Free install
    Deepan Ghimiray