[Cyber Security Terms](/glossary) CASB [Blog](/blog)[Breaches](/breaches)[Resources](/resources)[News](/news) [Cyber Security Terms](/glossary) # CASB ##### [Catherine Chipeta](/team/catherine-chipeta) updated Nov 11, 2021 ###### Contents ## What is a CASB? A [CASB (cloud access security broker)](https://www.upguard.com/blog/casb) is a cloud security tool that enforces security policies between users in an organization and cloud services. CASBs are one of five major security functions in the increasingly popular [SASE (Secure Access Service Edge) security model](https://www.upguard.com/blog/sase), alongside software-defined wide area network (SD-WAN), firewall-as-a-service (FWaaS), secure web gateway (SWG), [zero-trust network access (ZTNA)](https://www.upguard.com/blog/zero-trust). ## How Do CASBs Work? CASB’s functions are categorized by Gartner into four pillars: 1\. Visibility 2\. Compliance 3\. [Data Security](https://www.upguard.com/blog/data-security) 4\. Threat Protection ## CASB Types CASBs are categorized by their method of deployment. There are three main types of CASB: 1\. API-based CASB 2\. Agent-based CASB ([Reverse proxy](https://www.upguard.com/blog/proxy-server)) 3\. Agentless CASB ([Forward proxy](https://www.upguard.com/blog/proxy-server)) ## Key takeaways * CASBs consolidate security policies across all cloud services an organization uses. * They are fundamental to SASE, an emerging Gartner concept that converges network and security functions into a cloud-based model. * CASBs can be deployed through APIs or proxies. * * ###### Reviewed by No items found. ###### Author ##### [Catherine Chipeta](/team/catherine-chipeta) ###### Reviewed by ##### [Axel Sukianto](/team/axel-sukianto) ###### Join 27,000+ cybersecurity newsletter subscribers ## Read more about CASBs Learn more about CASB and the latest issues in cybersecurity. [UpGuard](/blog/casb) [What is a CASB (Cloud Access Security Broker)?](/blog/casb) #### [What is a CASB (Cloud Access Security Broker)?](/blog/casb) A CASB (cloud access security broker) is an intermediary between users, an organization, and a cloud environment. Learn more. [](/team/catherine-chipeta) [Catherine Chipeta](#) June 29, 2025 [UpGuard](/blog/sase) [What is SASE (Secure Access Service Edge)?](/blog/sase) #### [What is SASE (Secure Access Service Edge)?](/blog/sase) SASE (Secure Access Service Edge) is a network architecture that unifies network and security solutions via the cloud to enhance accessibility. [](/team/catherine-chipeta) [Catherine Chipeta](#) June 25, 2025 [View all blog posts](/blog) ## See UpGuard In Action Book a free, personalized onboarding call with one of our cybersecurity experts. [Contact sales](/demo) [Free demo](/demo) ## More from our blog Learn more about the latest issues in cybersecurity. [UpGuard](/blog/find-out-if-youre-exposed-on-the-dark-web) [Find Out if You're Exposed on the Dark Web](/blog/find-out-if-youre-exposed-on-the-dark-web) #### [Find Out if You're Exposed on the Dark Web](/blog/find-out-if-youre-exposed-on-the-dark-web) Answer 5 quick questions to predict what a dark web scan will find about your company. Then run the free scan to see your real exposure. [](/team/lance-turner) [Lance Turner](#) October 14, 2026 [UpGuard](/blog/upguard-named-leader-in-idc-marketscape) [The Evidence Is In: UpGuard Named a Leader in the IDC MarketScape for Worldwide Third-Party Risk Management](/blog/upguard-named-leader-in-idc-marketscape) #### [The Evidence Is In: UpGuard Named a Leader in the IDC MarketScape for Worldwide Third-Party Risk Management](/blog/upguard-named-leader-in-idc-marketscape) UpGuard has been named a Leader in the IDC MarketScape: Worldwide Third-Party Risk Management Services 2026 Vendor Assessment. Find out why. [](/team/cassy-van-eeden) [Cassy van Eeden](#) October 18, 2026 [UpGuard](/blog/your-first-dark-web-scan-report-explained) [Your First Dark Web Scan Report, Explained](/blog/your-first-dark-web-scan-report-explained) #### [Your First Dark Web Scan Report, Explained](/blog/your-first-dark-web-scan-report-explained) You scanned your domain. What do the results mean? [](/team/lance-turner) [Lance Turner](#) October 11, 2026 [UpGuard](/blog/ai-evidence-analysis-tools-for-tprm) [We Researched Four AI Evidence Analysis Tools for TPRM. Here’s What We Found.](/blog/ai-evidence-analysis-tools-for-tprm) #### [We Researched Four AI Evidence Analysis Tools for TPRM. Here’s What We Found.](/blog/ai-evidence-analysis-tools-for-tprm) We researched four AI evidence-parsing tools against four criteria that security teams often overlook. None nailed all four. [](/team/cassy-van-eeden) [Cassy van Eeden](#) September 29, 2026 [UpGuard](/blog/cybersecurity-horror-stories-2026) [12 Cybersecurity Horror Stories of 2026 (No Costume Required)](/blog/cybersecurity-horror-stories-2026) #### [12 Cybersecurity Horror Stories of 2026 (No Costume Required)](/blog/cybersecurity-horror-stories-2026) A warning ignored once becomes a headline. Read more about these 12 real 2026 cybersecurity incidents, and the sign each one gave before it made the news. [](/team/revashni-moodley) [Revashni Moodley](#) October 14, 2026 [UpGuard](/blog/good-security-rating-your-dark-web-exposure-says-otherwise) [Good Security Rating? Your Dark Web Exposure Says Otherwise](/blog/good-security-rating-your-dark-web-exposure-says-otherwise) #### [Good Security Rating? Your Dark Web Exposure Says Otherwise](/blog/good-security-rating-your-dark-web-exposure-says-otherwise) Scan your domain to see just how exposed you are on the Dark Web. [](/team/lance-turner) [Lance Turner](#) October 11, 2026 [View all blog posts](/blog) ### Sign up for our newsletter UpGuard's monthly newsletter cuts through the noise and brings you what matters most: our breaking research, in-depth analysis of emerging threats, and actionable strategic insights. ##### Free instant security score ## How secure is your organization? Request a free cybersecurity report to discover key risks on your website, email, network, and brand. * Instant insights you can act on immediately * Hundreds of risk factors including email security, SSL, DNS health, open ports and common vulnerabilities [Free score](/instant-security-score)