What Is CASB (Cloud Access Security Broker)? - Definition

What is CASB?

A CASB is an intermediary between users and cloud platforms that protect data in the cloud while addressing authorisation and visibility concerns of corporations leveraging cloud services. As Gartner explains it, CASBs address security gaps associated with third-party cloud services and platforms that are not under your control but that process and store your data. While cloud services offer a certain level of security, cloud security is a shared responsibility. The onus is on you to protect your users, your workloads and your data.

Cloud app security has become an essential component of a comprehensive enterprise defence in today’s cloud-driven world. Gartner estimates that, by 2022, 60% of enterprises will incorporate CASB into their security toolbox – up from less than 20% today.

History of CASB

The term “CASB” was first coined in 2012 when the idea of using a security broker for cloud resources became a necessity. In 2013, the first CASB vendor was introduced to the market, but the introduction of Office 365 is considered the start of the CASB era. As more companies leverage cloud applications, the need for CASB increases.

How It Works

In a hybrid cloud environment, data synchronises between the cloud and on-premises resources. It provides encryption services so that data is protected from eavesdropping, and it provides identity management so that only authorised users can access resources. These users can share documents and data with other users, and organisations can obtain visibility into the ways documents are shared and accessed. It also provides protection from malware and malicious software that can steal data from the cloud.

What is CASB Commonly Used For?

Administrators determine the right security strategies, and a CASB helps enforce these strategies. It provides the defences necessary to protect data using security layers. For example, if your organisation allows users to connect to cloud resources using their own devices (e.g., smartphones and tablets), a CASB will let administrators monitor data and control access to it across numerous endpoints.

A CASB handles several security features common in the cloud. These security features protect data from external and internal hackers as well as malware. CASB can be used for:

Single Sign-On (SSO) service: Users can authenticate from one location and get access to multiple systems with only one username and password.
Encryption: A CASB will encrypt data at-rest (on storage devices) and in-transit (as it moves across the network) to avoid eavesdropping and man-in-the-middle (MitM) attacks.

Compliance tools: With so many moving parts, CASB compliance tools report on every system so that administrators can identify any non-compliant systems.
Traffic analytics: Monitoring the environment is a big component in effective cybersecurity, and CASB tools provide reports based on user behaviours and traffic patterns so that administrators can identify anomalies.

What are the Four Pillars of CASB?

As you research into CASB, you’ll find that there are four pillars that define CASB services and what you get from them. Here are the four pillars of CASB:

Visibility: Monitoring and watching resource usage provides visibility needed to detect suspicious behaviour. Administrators can detect suspicious access requests, uploaded malicious files, and security vulnerabilities from poor access controls. It gives administrators an opportunity to train users on the best security policies for shared resources.
Compliance: Compliance regulations oversee many of the cybersecurity factors necessary to protect cloud data. Organisations out of compliance can suffer from hefty fines, so a CASB ensures that organisations have the necessary access tools and monitoring in place to keep them compliant.

Data Security: Sensitive data such as customer information, intellectual property, and secrets might be stored in the cloud. The primary pillar and arguably the most important is the security offered including access controls, encryption, tokenised data, permission management, data discovery, and remediation.
Threat Detection: Along with monitoring, threat detection mitigates any suspicious activity. The threat detection pillar identifies external and internal threats, mitigates them, and sends a notification to administrators.

Why You Need CASB

Security and compliance concerns with cloud apps and services are pushing more and more enterprises to implement CASB solutions. These include:

“Shadow IT” and the proliferation of third-party apps: When CASBs first came on the scene, enterprises deployed them primarily to curb “Shadow IT” (cloud apps and services used without the explicit approval of IT). Now enterprises also face the challenge of governing hundreds and sometimes thousands of third-party apps and scripts with OAuth permissions (which use tokens instead of passwords) to access enterprise data. These third-party apps add more features to Office 365, G Suite, Box, and other platforms. But some are poorly built or overtly malicious. And, once an OAuth token is authorised, access continues until it’s revoked. After auditing each cloud app for its security controls, such as certifications, and other risks, such as broad data permissions, IT teams can make educated decisions on access controls for risky cloud apps and can promote the use of “safe” cloud services.
Cloud account compromise: Apps and data in the cloud are often accessed by cybercriminals through compromised cloud accounts. Proofpoint recently analysed more than 100,000 unauthorised logins across millions of monitored cloud accounts and found that 90% of tenants are targeted by cyber attacks. Sixty percent of tenants have at least one compromised account in their environment. These typically begin with brute-force attacks – where threat actors submit multiple user names or passwords in an attempt to guess user credentials correctly so they can access an account. Another method is credential phishing, where they try to get users to part with their passwords through socially engineered emails. Once they have the credentials, attackers then leverage these cloud accounts to pose as legitimate users in order to get employees to wire funds to them or release corporate data. Threat actors also hijack email accounts to distribute spam and phishing emails.

Loss of intellectual property: The risk of losing trade secrets, engineering designs and other corporate-sensitive data is very real when employees use cloud-based collaboration or messaging tools to share files and information. Employee negligence or lack of training can result in oversharing of files via public links that can be accessed by anyone. Insider threats are also common. A common example is theft of customer sales records from CRM services by sales personnel who plan on leaving the company. Enterprises can increase visibility to data handling in the cloud and improve data security by employing user-centric policies to control access to cloud services and data via CASB solutions.
Stricter regulations and bigger fines: Organisations in virtually all sectors are finding that maintaining compliance has become a daunting task. Many regulations and industry mandates now require you to know where your data is and how it’s shared in the cloud. Violations of recent data privacy and residency regulations can result in hefty fines. For example, violators of GDPR can be fined up to 4% of worldwide annual revenue. CASBs can lighten the compliance burden and spare you the headaches at audit time.
Visibility into cloud usage: Whether it’s to protect data or obtain insights into the ways cloud services are used, a CASB provides the visibility needed for security and future scaling. A CASB can help organisations plan for future resources so that performance is always maintained. It also helps administrators review threat activities and provision security resources to mitigate attacks.

How CASBs Strengthen Your Security Posture

Now that you know why you need a CASB, let’s take a look at the capabilities of CASBs. They perform several key functions that go beyond enterprise firewalls and web gateways:

Cloud app governance: CASBs govern cloud apps and services by offering a centralized view of your cloud environment, with details like who’s accessing what apps and data in the cloud from where and from which device. Because usage of cloud apps has become so pervasive, CASBs catalog cloud services (including third-party OAuth apps), rate the risk level and overall trustworthiness of cloud services and assign them a score. CASBs even provide automated access controls to and from cloud services based on cloud service risk scores and other parameters, such app category and data permissions.
Defense against cloud threats: CASBs can help detect cloud threats by monitoring suspicious or excessive logins and then sending out alerts. CASBs also use advanced anti-malware and sandbox tools to block and analyze threats. And in some cases, CASB vendors rely on their own global research and third-party feeds to help identify the behaviors and characteristics of current and emerging cloud-based attacks. Today’s sophisticated CASB solutions also allow you to configure policies for automated remediation of cloud threats. For preventative measures, you can configure user-centric adaptive access controls based on the user’s role (such as privileges and VIP status), the risk level associated with the login and other contextual parameters, such as user’s location, device hygiene and others.
Securing sensitive data: Detection and removal of public and external shares of files, as well as data loss prevention (DLP), are critical components of a CASB solution. For example, CASBs enable you to set and enforce data security policies to allow users to access only certain categories of data based on their privileges. In most CASB solutions, DLP works natively and is also integrated with enterprise data protection solutions.
Compliance for the cloud: CASBs can be a big help when it comes to proving that you are exercising proper governance over cloud services. Through visibility, automated remediation, policy creation and enforcement and reporting capabilities, CASBs enable you to stay compliant with industry and government regulations. These include regional mandates, like European Union General Data Protection Regulation (GDPR), and industry standards and rules, like the Health Insurance Portability and Accountability Act (HIPAA).

CASB Use Cases

CASB provides the security resources necessary for data security in the cloud. A CASB has the web gateways, firewalls, policy and governance, and access controls a business needs to protect data. A corporation that does not have the resources for security can leverage CASB offerings so that security can be integrated with provisioning infrastructure.

What Do You Need to Know When Shopping Around?

Every provider has their own offerings, but you should find a provider that has the security controls that integrate well into current infrastructure. Your chosen provider should have the four pillars included in their offering, and they should have the following capabilities:

Cloud app discovery: Find unused or stale apps still accessible by users.
Risk and data governance: Configure access and authorisation rules.
Activity monitoring: Obtain visibility and insights into the way data is access and used.
Threat prevention: Detect and mitigate threats automatically.
Data security: Use data loss prevention to block attackers and alert administrators.

Activity analytics: Provide visualisation that helps administrators make decisions to better protect data.
Endpoint access control: Manage mobile endpoints and monitor their data access usage.
Remediation option: Fix issues after they occur so that data can be restored.
Deployment considerations: Support API-based deployment and automation of data transfers and provisioning.
Delivery infrastructure: Reduce latency and mitigate distributed denial-of-service (DDoS) attacks.

Proofpoint CASB

Proofpoint CASB provides granular visibility into your data, access controls, and any ongoing threats. It provides an overall view of the way your data is used and gives administrators insight into risks that could create a data breach incident. Administrators can view suspicious authentication attempts, data loss prevention alerts and dashboards that provide detail into your security.

Proofpoint Named a Challenger in the 2020 Gartner Magic Quadrant for CASBs

Proofpoint was recognised in Gartner’s Magic Quadrant for Cloud Access Security Brokers for the third year running. Gartner named Proofpoint a Challenger in its report based on our ability to execute and completeness of vision.

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