--- title: How We Added WebAuthn to a Browser-Based RDP Client description: A deep technical account of building the first non-Windows RDP client with WebAuthn redirection support, developed for Palo Alto's Prisma Browser. The team... canonical: https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How We Added WebAuthn to a Browser-Based RDP Client | daily.dev og:description: A deep technical account of building the first non-Windows RDP client with WebAuthn redirection support, developed for Palo Alto's Prisma Browser. The team... og:url: https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7 og:image: https://api.daily.dev/og/posts/L9F13E4P7.png og:image:alt: How We Added WebAuthn to a Browser-Based RDP Client 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 We Added WebAuthn to a Browser-Based RDP Client **[Unit 42](https://daily.dev/sources/unit42)** · 11 min read · 0 upvotes · 0 comments ## Summary A deep technical account of building the first non-Windows RDP client with WebAuthn redirection support, developed for Palo Alto's Prisma Browser. The team discovered that the MS-RDPEWA protocol spec was incomplete, that standard browser APIs (navigator.credentials) cannot accept a pre-computed clientDataHash, and that Microsoft's own mstsc.exe bypasses the public webauthn.dll API entirely via an undocumented DVC plugin path. They reverse-engineered mstsc.exe using IDA Pro and Frida to uncover the private CtapCborDecodeRpcRequest call chain that handles hash-only requests from older Windows servers. The solution involved a custom Chromium extension API that passes clientDataHash directly to the FIDO2 stack, a WebAssembly DVC plugin, and a TypeScript CBOR protocol layer. The implementation supports USB keys, Touch ID, Windows Hello, and phone-as-authenticator via caBLE/Hybrid, and works against both modern and legacy Windows server versions. FreeRDP has since added similar support in version 3.25.0. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Amazon WorkSpaces Secure Browser now supports WebAuthn redirection for local Chromium browsers](https://daily.dev/posts/amazon-workspaces-secure-browser-now-supports-webauthn-redirection-for-local-chromium-browsers-tmlmak4nh) · AWS · 0 upvotes · 0 comments - [Going fully passwordless in hybrid enterprise environments](https://daily.dev/posts/going-fully-passwordless-in-hybrid-enterprise-environments-leiyjgdhr) · CSO Online · 0 upvotes · 0 comments - [Modernize authentication with passkeys, digital credentials, and more](https://daily.dev/posts/modernize-authentication-with-passkeys-digital-credentials-and-more-nzvsxhett) · Chrome Developers · 1 upvotes · 0 comments - [39 New Methods That Compromise Passkey Authentication](https://daily.dev/posts/39-new-methods-that-compromise-passkey-authentication-z1hysnxm6) · BleepingComputer · 1 upvotes · 0 comments - [Using Passkeys to Sign In to Websites and Apps](https://daily.dev/posts/using-passkeys-to-sign-in-to-websites-and-apps-cbz70me3e) · Security Boulevard · 0 upvotes · 0 comments --- Tags: [#reverse-engineering](https://daily.dev/tags/reverse-engineering), [#chromium](https://daily.dev/tags/chromium) [View this post on daily.dev](https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7) ```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 We Added WebAuthn to a Browser-Based RDP Client","url":"https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7"},"datePublished":"2026-07-09T07:49:43.933Z","dateModified":"2026-07-09T07:50:31.189Z","description":"A deep technical account of building the first non-Windows RDP client with WebAuthn redirection support, developed for Palo Alto's Prisma Browser. The team...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/67e2208899d1e76d3014c9280084472b?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/67e2208899d1e76d3014c9280084472b?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Unit 42","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":"Unit 42","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/5b55ca8d2ae04181939041fbc9d78160","url":"https://daily.dev/sources/unit42"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-we-added-webauthn-to-a-browser-based-rdp-client-l9f13e4p7","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"reverse-engineering,chromium","timeRequired":"PT11M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Unit 42","item":"https://daily.dev/sources/unit42"},{"@type":"ListItem","position":3,"name":"How We Added WebAuthn to a Browser-Based RDP Client"}]} ```