Ad-blocker circumvention System Synoshur Ad-blocker circumvention System

Ad Blockers work by using one or both of two different methods The first method is to block outbound requests at the local (LAN) network- level. A browser extension can forbid connections to known ad servers, or to any specified host, domain or IP address. Or, instead of a browser extension, outbound requests can be disallowed by any intermediary hardware or software between the requesting client and the Internet, e.g. at a forward proxy, the gateway, a router or switch, etc. The second method is to use JavaScript to manipulate the HTML and/or CSS that specify the Document Object Model (DOM-level) of a Web page. Each page a browser has open is represented by its own DOM. The DOM determines how the page is rendered on screen. Both the JavaScript included within a page, and the JavaScript within a browser extension, have equal abilities to modify the page’s DOM via HTML/CSS manipulations, but neither can alter the other’s JavaScript code.

Synoshur Ad Blocker Circumvention System Consists of Four Major Components End user: Client JavaScript (cross-browser implementation) proactive ad management via stealthy HTML & CSS manipulations Customer: Web Server Middleware (minimal onsite footprint) dynamic HTML rewriting, versions for all major Web server platforms Synoshur Private CDN & API: Proxy & Caching Server cloud-hosted (domestic or global) API, CDN, proxies, caching & DNS Synoshur HQ: In-House Systems Management web front-end to the API, code distribution, customer licensing & analytics

Synoshur uses clever techniques to defeat both blocking methods. The first technique works at the network level and avoids request blocking altogether by simply NOT making requests to any ad servers. For a customer website located at www.example.com, Synoshur would provide a corresponding private CDN server(s) in the cloud using a hostname like cdn.example.com. The customer would have most or all of their static content files served from the CDN, including the most important or most often used resources, like logos & header images, CSS files, etc. While serving HTML pages, all URLs to static files AND all the URLs to ad servers are rewritten to point to the CDN and specific file names are replaced by ID numbers. The CDN is aware of which IDs map to the ads on the page, so for those requests, the CDN fetches ads from the ad servers and forwards them to the client. If an ad blocker denied access to the CDN, it would also be blocking images, CSS, JavaScript files, etc., rendering the website unusable for all ad blocker users. Therefore, blocking at the network level will no longer be an option.

Synoshur uses clever techniques to defeat both blocking methods. For each Web page that displays ads, the customer’s developers will mark each HTML container that holds an ad (typically iframes) using the CSS class “synoshur”. A minimal piece of software called middleware, made available for each of the major Web server platforms, will be added to the servers at or near the end of the of the HTTP response cycle. The middleware scans all outgoing HTML, removes ad containers, then obscures their locations. Much like in the first technique, generic URLs with IDs replace all requests to ad server URLs with requests to the private CDN. Embedded into the page is some encrypted data which the page’s JavaScript will be able to access, but the browser extensions will not. Once again the CDN fetches ads on behalf of the browser and they are returned along with the other static content. After decrypting the embedded data, the browser is able to reconstruct the original structure of the page inserts the ads where they should be. Finally, the page’s JavaScript monitors each ad to detect and reverse any tampering.