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. Facebook. Even if it is circumvented, potential attackers would be able to fixate only on an origin they can achieve code execution on, making cookie fixation vectors redundant. 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. 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. However, support for SNI isn’t universal, which made this solution less viable. We hash the index of a cookie using the client-side key so that the cookie isn’t traceable back to the user when the key is not present. , a browser identifier used for site integrity purposes. IPv4-in-IPv6 encapsulation, where we can encapsulate the entire IPv4 space within a single free data IPv6 subnet. Do you want to join Facebook? We’d like to thank Berk Demir for his help on this work. We make sure that the outer frame is always the top frame with JavaScript and. Only a few carriers gateways supported IPv6 in this way. It didn’t require cooperation from the website owner. Nemo: Data discovery at Facebook. The proxy can then verify that the writing origin indeed possessed the token to write to the cookie’s target domain, and stores it in the server-side cookie jar, sending it to the client again the next time the page is requested. JavaScript code is still allowed to run, and resources are still fetched. Production Engineering at Facebook is a hybrid between software and systems engineering; it keeps Facebook running smoothly and scaling efficiently. Connect with friends, family and other people you know. Facebook believes in building community through open source technology. We assume that a benign origin will not deliberately circumvent the inner-outer messaging protocol. The outer frame can be escaped only by directly navigating to another site. Production Engineering is a hybrid software/systems group that ensures Facebook's services run smoothly and have the capacity for future growth. A production engineer wants to … 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. We have developed Discover specifically to address and incorporate those recommendations into a new product that supports connectivity. Following the launch of Discover in Peru, we’re planning to roll out additional Discover trials with partner operators in a number of other countries where we have been beta testing product features, including Thailand, the Philippines, and Iraq. Want to see the real deal? The inner frame will remove it when it gets the outer frame’s confirmation. It required minimal intervention on the proxy side. Production Engineering Production Engineering at Facebook is a hybrid between software and systems engineering; it keeps Facebook running smoothly and scaling efficiently. If no, delete the session, delete all the cookies, and navigate to a safe origin. Production Engineers work with all of Facebook's other product and infrastructure teams, sometimes embedded in those teams. 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. 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. As we’ve continued working on Free Basics, we’ve listened to feedback and recommendations from civil society and other stakeholders. We use, Since the origins are now separate, our bootstrap process becomes a two-step process. The document.cookie allows JavaScript to read and modify cookies that aren’t marked HttpOnly. Operators can then allowlist traffic to this destination more easily and keep their configurations simple. Since the origins are now separate, our bootstrap process becomes a two-step process. A product manager wants to see country-based usage trends over the past quarter. It will then attach a JSON payload to the response page. Join or log in to Facebook Email or phone. Forgotten account? We require POSTs to carry a query parameter with the datr seen when the page loaded. Client-side code is injected to shim document.cookie and make these cookies visible to other scripts, as if they were real client-side cookies. Server-side cookies are encrypted with an. Password. To force the client to prove it is eligible to set cookies on a specific domain, the server will send, in addition to the JSON payload, a list of cryptographic tokens for each of the origins at which the requesting origin is allowed to set cookies. For instance, a cookie set on any subdomain at. The team writes code and debugs hard problems in live production that impact more than 2 billion people around the world. 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. For validation, we need a way for a third-party page to query the ickt value and validate it. Supporting this securely is challenging in a system that maintains the cookies on the server. Explore our latest projects in Artificial Intelligence, Data Infrastructure, Development Tools, Front End, Languages, Platforms, Security, Virtual Reality, and more. Trusting the browser’s CORS capabilities would not be enough in this case — origin a.example.com trying to set a cookie on example.com will be blocked by the browser, since these origins are siblings and not hierarchical. Actions. Log into Facebook to start sharing and connecting with your friends, family, and people you know. 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. Within the inner frame, we inject a script into every proxied page we serve. This includes our work on technologies like Terragraph, our collaboration with mobile operators on efforts to expand rural access, our work as part of the Telecom Infra Project, and programs like Free Basics. 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). 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. 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. A customized DNS resolver then resolves IPv4 recursively and responds with encapsulated IPv6 answers. We solve this by bootstrapping the secure origin with the ickt cookie first and giving the user an encrypted version of ick, with a key known only to the proxy. A data engineer is interested in seeing how his latest experiment influenced latency. Our connectivity efforts focus on expanding internet access and adoption around the world. To accommodate the limited functionality of many mobile operator gateways, we considered alternative architectures, including: Neither of these was a viable solution. The client-side shim for document.cookie takes care of resolving and embedding the token in the actual cookie text that is sent to the proxy. Now Accepting Applications for Discover Production Engineering! To support a model serving any website, with the ability to run scripts more securely, we needed to significantly rethink our architecture to prevent threats, such as scripts being able to either read or fixate the user’s cookies. In either case, the attacker cannot simultaneously know and force a particular ick value on a user. They use almost every new framework and things I was planning on learning in 2020 are now a requirement all of a sudden. We then compare the query param with the datr cookie seen in the request. We have developed Discover specifically to address and incorporate those recommendations into a new product that supports connectivity. This includes our work on technologies like, , our collaboration with mobile operators on efforts to expand. Browsers would have to request a specific domain through Server Name Indication (SNI), so the proxy would know where to connect. Facebook believes in building community through open source technology. The Production Engineering team at Facebook carefully plans and builds infrastructure to ensure service uptime and reliability even through such spikes. We do this by embedding the third-party site within an