PEs work within Facebook's product and infrastructure teams to make sure our products and services are reliable and scalable. Production Engineers at Facebook are hybrid software/systems engineers who ensure that Facebook's services run smoothly and have the capacity for future growth. A cooperative solution where websites can allocate a subdomain (e.g.. Server-side cookies are encrypted with an. I've been in Production Engineering @FB for almost 2.5 years now, so I will attempt to add some details, but Joe Gasperetti already did an amazing job with his answer. Log In. But in a proxy server configuration, the client is interacting with the proxy, and the proxy acts as a client to the site. Explore our latest projects in Artificial Intelligence, Data Infrastructure, Development Tools, Front End, Languages, Platforms, Security, Virtual Reality, and more. That new approach required us to first build a web-based proxy service where the operator could make the service available free to a single domain: freebasics.com. To address these concerns, we initially imposed some straightforward limitations, including which sites could be visited with Free Basics and the inability to run scripts. We require POSTs to carry a query parameter with the datr seen when the page loaded. It will then attach a JSON payload to the response page. It allowed for direct end-to-end communication between client and server. To help personalize content, tailor and measure ads, and provide a safer experience, we use cookies. However, it can be copied by phishing sites that impersonate Discover. Back to Jobs. Before, we could set ick in the same request we provision localStorage with ickt. To prevent this, we use a classic CSRF prevention method. To accommodate the limited functionality of many mobile operator gateways, we considered alternative architectures, including: Neither of these was a viable solution. By choosing to go with this solution, we then had to solve for other possible outcomes, specifically: Up to this point, the protections we have implemented have accounted for synchronous fixations, but they can also occur asynchronously. References to the domain at this point will change to our new domain, a similarly origin-collapsed, On signup, we generate a new, secure random, When the page loads, we compare the embedded. Anonymity is preserved because we do not leak it to the third-party site — the ick cookie is missing, so we cannot use the cookie jar. Before, we could set, We solve this by bootstrapping the secure origin with the, In either case, the attacker cannot simultaneously know and force a particular, Turbine: Facebook’s service management platform for stream processing, Rebuilding our tech stack for the new Facebook.com, SuperCell: Reaching new heights for wider connectivity, The economic impact of subsea cables in Africa, Results of Oregon project environmental analysis, Making aerial fiber deployment faster and more efficient, Building a transformative subsea cable to better connect Africa. The latter has become more of an issue over time as many websites, including mobile sites, have started to rely on JavaScript for critical functionality, including content rendering. In an effort to be more inclusive in our language, we have edited this post to replace “whitelist” with “allowlist.”. Unlike web clients, which can make use of cookies directly from the site, the proxy service requires a different setup. Now Accepting Applications for Discover Production Engineering! The following section shows in detail how we mitigate session fixation and other attacks, such as phishing and clickjacking. To prevent this, we use a classic CSRF prevention method. These tokens are salted with the ick value, so they cannot be transferred between users. From raw materials to the finished product, manufacturing engineers work to improve the production process, using the most cost-effective methods while reducing the We’d like to thank Berk Demir for his help on this work. A product manager wants to see country-based usage trends over the past quarter. To prevent this, the server adds style="display:none" to the element of every page. We have developed Discover specifically to address and incorporate those recommendations into a new product that supports connectivity. Below, we walk through the model we built, the unique architecture choices we made along the way, and the steps we’ve taken to mitigate risks. Production Engineers at Facebook are hybrid software/systems engineers who ensure that Facebook's services run smoothly and have the capacity for future growth. This means we have to use a different protocol: We decided to separate the rewrite origin from the secure origin so that they do not share the same host suffix as per the Public Suffix List. If Free Basics were to set client-side cookies for each site under, The domain namespace constraints that we needed to implement also precluded the use of sibling and hierarchical cookies. However, support for SNI isn’t universal, which made this solution less viable. Explore our latest projects in Artificial Intelligence, Data Infrastructure, Development Tools, Front End, Languages, Platforms, Security, Virtual Reality, and more. Neither of these was a viable solution. But as long as the person hasn’t entered any input to the page, the browser does nothing a potential attacker couldn’t have done simply by visiting the site — unless the site is already vulnerable to cross-site request forgery (CSRF). More inside scoop? We use www.0.discoverapp.com for storing the secure copy of ickt (as a cookie), and move all third-party origins under 0.i.org. Because certain browsers, such as Opera Mini (popular in many countries where Discover operates), do not support localStorage, we are unable to store the ick and ickt values. Today. Facebook's Discover Production Engineering Program. A place for engineers and engineering students to talk about their education, career and anything engineering related. If the script waits too long or gets a reply from an unexpected origin, we’ll navigate the frame to an error screen with no third-party content (our “Oops” page), because it’s possible the outer frame is either not there or is different than the inner frame expects. Free Basics stores user cookies on the server side for several reasons: To allow the proxy service to access this server-side cookie jar, Free Basics leverages two client-side cookies: To help protect user privacy and security when storing their cookies in a server-side cookie jar, we make sure that: Allowing scripts to run risks the fixation of server-side cookies. Production Engineering at Facebook is a hybrid between software and systems engineering; it keeps Facebook running smoothly and scaling efficiently. If validation fails, we navigate the user to the “Oops” page. A customized DNS resolver then resolves IPv4 recursively and responds with encapsulated IPv6 answers. 2,124 talking about this. Facebook’s infrastructure is set up to accommodate different types of traffic patterns based on typical usage or special events. This header is used by websites to prevent exposure to certain types of attacks, such as clickjacking. We anticipate that Discover will be live in these additional countries in the coming weeks, and we’ll explore additional trials where partner operators want to participate. Ultimately, we decided that the best possible architecture would be origin collapsing, where our proxy runs within a single origin-collapsed domain namespace under freebasics.com. Today, Facebook Connectivity and our partners at Bitel, Claro, Entel, and Movistar are launching a trial of Discover in Peru. We assume that a benign origin will not deliberately circumvent the inner-outer messaging protocol. Since the origins are now separate, our bootstrap process becomes a two-step process. From backend services like our Hadoop data warehouses, to frontend services like News Feed, to infrastructure components like our caching infrastructure, load balancing, and deployment systems, the Production Engineering team keeps Facebook running. They are embedded in every one of Facebook's product and infrastructure teams, and are core participants in every significant engineering effort underway in the company. The solution we came up with needed to address cookie fixation, so instead of trying to parse and block certain script calls, we decided to detect it as it happens and render it useless. ), secure origin (outer frame), and rewrite origin (inner frame). Each has a different need: Here’s a representation of the bootstrap process for most modern mobile browsers: It’s important to note that to avoid reflection, the bootstrap endpoint at the secure origin always issues a new ick and ickt; ick never depends on user input. We prevent malicious links from navigating away from Discover by preventing top navigation using