--- title: How Auth0 Tenant Access Control List Empowers Customers... description: Auth0's Tenant Access Control List (ACL) feature helped a customer block over 21 million fraudulent signup requests during a sustained attack in September... canonical: https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How Auth0 Tenant Access Control List Empowers Customers Under Fire | daily.dev og:description: Auth0's Tenant Access Control List (ACL) feature helped a customer block over 21 million fraudulent signup requests during a sustained attack in September... og:url: https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3 og:image: https://api.daily.dev/og/posts/avle6lkU3.png og:image:alt: How Auth0 Tenant Access Control List Empowers Customers Under Fire og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How Auth0 Tenant Access Control List Empowers Customers Under Fire **[Auth0](https://daily.dev/sources/auth0)** · 4 min read · 0 upvotes · 0 comments ## Summary Auth0's Tenant Access Control List (ACL) feature helped a customer block over 21 million fraudulent signup requests during a sustained attack in September 2025. The attackers initially used specific JA3/JA4 TLS fingerprints to flood the system with fake signups at 40x normal volume. When they pivoted tactics after the first block, the customer used Tenant ACL to independently identify and block new malicious fingerprints in real-time without waiting for support intervention. This edge-level filtering prevented malicious traffic from reaching the application, avoiding rate limit impacts on legitimate users while the security team continuously updated rules to stay ahead of evolving attacker tactics. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Detecting Signup Fraud: 3 Ways to Use Auth0 Logs to Protect Your Business](https://daily.dev/posts/detecting-signup-fraud-3-ways-to-use-auth0-logs-to-protect-your-business-0fg01wkwl) · Auth0 · 0 upvotes · 0 comments - [Auth0 for Scaling Apps: Advanced Security and Authentication](https://daily.dev/posts/auth0-for-scaling-apps-advanced-security-and-authentication-ewqw4ylxe) · Auth0 · 0 upvotes · 0 comments - [Bulletproof Hosting Defense: Mitigating the Proxy Threat with Auth0](https://daily.dev/posts/bulletproof-hosting-defense-mitigating-the-proxy-threat-with-auth0-26xqk1ngo) · Auth0 · 0 upvotes · 0 comments - [A Comprehensive Guide to Auth0 Security for Identity Attacks](https://daily.dev/posts/a-comprehensive-guide-to-auth0-security-for-identity-attacks-oiypqqvmq) · Auth0 · 0 upvotes · 0 comments - [September 2025 in Auth0: Auth0 for AI Agents and more](https://daily.dev/posts/september-2025-in-auth0-auth0-for-ai-agents-and-more-e3dgcpjzk) · Auth0 · 1 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#authentication](https://daily.dev/tags/authentication), [#auth0](https://daily.dev/tags/auth0), [#fraud-detection](https://daily.dev/tags/fraud-detection) [View this post on daily.dev](https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"How Auth0 Tenant Access Control List Empowers Customers Under Fire","url":"https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3"},"datePublished":"2026-01-20T18:49:00.593Z","dateModified":"2026-01-20T18:50:53.145Z","description":"Auth0's Tenant Access Control List (ACL) feature helped a customer block over 21 million fraudulent signup requests during a sustained attack in September...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b4b691a3583c73aba434a037a062f3a4?_a=AQAEulh","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b4b691a3583c73aba434a037a062f3a4?_a=AQAEulh","isAccessibleForFree":true,"articleSection":"Auth0","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Auth0","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/6510ffa7350449618fbacdddae663b82","url":"https://daily.dev/sources/auth0"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-auth0-tenant-access-control-list-empowers-customers-under-fire-avle6lku3","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,authentication,auth0,fraud-detection","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Auth0","item":"https://daily.dev/sources/auth0"},{"@type":"ListItem","position":3,"name":"How Auth0 Tenant Access Control List Empowers Customers Under Fire"}]} ```