Simon Willison’s Weblog

Blogmarks tagged facebook

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What is a Self-XSS scam? Facebook link to this page from a console.log message that they display the browser devtools console, specifically warning that “If someone told you to copy-paste something here to enable a Facebook feature or hack someone’s account, it is a scam and will give them access to your Facebook account.” # 8th April 2019, 6:01 pm

XARs: An efficient system for self-contained executables (via) Really interesting new open source project from Facebook: a XAR is a new way of packaging up a Python executable complete with its dependencies and resources such that it can be distributed and executed elsewhere as a single file. It’s kind of like a Docker container without Docker—it uses the SquashFS compressed read-only filesystem. I can’t wait to try this out with Datasette. # 13th July 2018, 7 pm

Migrating Messenger storage to optimize performance (via) Fascinating case-study of a truly gargantuan migration. Messenger has over a billion users, and Facebook successfully migrated its backend storage from HBase to their MyRocks database (a fork of MySQL with a storage engine built on their SSD-optimized RocksDB key/value library) without any user-visible downtime. They ended up using two migration paths: one for the 99.9% of regular accounts, and a separate path for extremely high volume accounts (businesses with very active chat bots or support systems). # 27th June 2018, 3:05 pm

Pyre: Fast Type Checking for Python (via) Facebook’s alternative to mypy. “Pyre is designed to be highly parallel, optimizing for near-instant responses so that you get immediate feedback, even in a large codebase”. Like their Hack type checker for PHP, Pyre is implemented in OCaml. # 11th May 2018, 5:47 pm

Upgrades to Facebook’s link security (via) Facebook have started scanning links shared on the site for HSTS headers, which are used to indicate that an HTTP page is also available over HTTPS and are intended to be cached by browsers such that future HTTP access is automatically retrieved over HTTPS instead. Facebook will now obey those headers itself and link directly to the HTTPS version. What a great idea: all sites with sophisticated link sharing (where links are fetched to retrieve extracts and images for example) should do this as well. # 5th March 2018, 3:32 pm

Why Facebook open-sourced its datacenters. Jon Stokes speculates that Facebook plan to use open source hardware to compete with Google at datacenter efficiency . This isn’t a new pattern. Years ago when I worked at Yahoo! I was furiously jealous of the secret sauce technologies that allowed Google to build big applications faster than anyone else, such as BigTable and map/reduce. Today, the open source world has created better, free alternatives—sponsored in part by Facebook, Yahoo! and other Google competitors. # 9th April 2011, 7:54 am

The Inside Story of How Facebook Responded to Tunisian Hacks (via) “By January 5, it was clear that an entire country’s worth of passwords were in the process of being stolen right in the midst of the greatest political upheaval in two decades.”—which is why you shouldn’t serve your login form over HTTP even though it POSTs over HTTPS. # 24th January 2011, 6:06 pm

Facebook’s Instant Personalization: An Analysis of Fundamental Privacy Flaws (via) Oh FFS. “Instant Personalization” means you visit one of Facebook’s “partner websites” and Facebook instantly tells them your full identity and gives them access to full Facebook connect functionality—without you performing any action other than visiting the site. This will not end well. # 2nd October 2010, 11:53 pm

“Likejacking” Takes Off on Facebook. The Facebook Like button is vulnerable to Clickjacking, and is being widely exploited. Since Likes show up in your Facebook stream, it’s an easy attack to make viral. The button is implemented on third party sites as an iframe, which would seem to me to be exploitable by design (just make the iframe transparent in the parent document and trick the user in to clicking in the right place). I can’t think of any way they could support the embedded Like button without being vulnerable to clickjacking, since clickjacking prevention relies on not allowing your UI elements to be embedded in a hostile site while the Like button’s functionality depends on exactly that. # 3rd June 2010, 10:01 am

The Evolution of Privacy on Facebook. Brilliant infographic showing exactly how the visibility of different aspects of your Facebook profile has changed in increments since 2005. Also a nice example of Processing.js in action. # 9th May 2010, 11:53 am

Facebook’s Open Graph Protocol from a Web Developer’s Perspective. Best explanation I’ve seen yet of what the Open Graph protocol actually does. Add the RDFa-inspired metadata and a Like button to a standard web page representing a place, group, product, website or one of another limited set of object types and people can “Like” it just like they might join a fan page within Facebook itself. You can then send news feed updates to all of that page’s subscribers. The bootstrapped metadata can then benefit other services as well. # 26th April 2010, 1:21 pm

The new Facebook API exposes the events you attend to anyone on the Internet. I’m generally impressed by the new set of Facebook APIs—they’re a whole lot easier to work with than the older stuff—but they’re also clearly a bit half-baked and the privacy model needs some urgent work. The Graph API allows to to see all “open” events that any user has attended or is attending, which can exposes things like their friend’s home addresses. Yes, this means you can stalk Mark Zuckerberg. # 26th April 2010, 12:08 pm

Fear and Loathing in Farmville. “At multiple times during the conference, [Daniel] James expressed his serious ethical qualms over the path social gaming was laying for the industry. So many of the methods for making money are thinly-veiled scams that simply exploit psychological flaws in the human brain.” # 21st March 2010, 10:13 am

Facebook Adds Code for Clickjacking Prevention. Clever technique: Facebook pages check to see if they are being framed (using window.top) and, if they are, add a div covering the whole page which causes a top level reload should anything be clicked on. They also log framing attempts using an image bug. # 13th March 2010, 10:42 am

Some People Can’t Read URLs. Commentary on the recent “facebook login” incident from Jono at Mozilla Labs. I’d guess that most people can’t read URLs, and it worries me more than any other aspect of today’s web. If you want to stay safe from phishing and other forms of online fraud you need at least a basic understanding of a bewildering array of technologies—URLs, paths, domains, subdomains, ports, DNS, SSL as well as fundamental concepts like browsers, web sites and web servers. Misunderstand any of those concepts and you’ll be an easy target for even the most basic phishing attempts. It almost makes me uncomfortable encouraging regular people to use the web because I know they’ll be at massive risk to online fraud. # 2nd March 2010, 10:16 am

Making Facebook 2x Faster. Facebook have a system called BigPipe which allows them to progressively send their pages to the browser as the server-side processing completes to optimise client loading time. Anyone reverse engineered this yet to figure out how they actually do it? # 19th February 2010, 9:14 am

HipHop for PHP: Move Fast. Facebook have open-sourced their internally developed PHP to C++ compiler. They serve 400 billion PHP pages a month (that’s more than 150,000 a second) so any performance improvement dramatically reduces their hardware costs, and HipHop drops the CPU usage on their web servers by an average of 50%. “We are serving over 90% of our Web traffic using HipHop, all only six months after deployment”. # 2nd February 2010, 6:59 pm

tipsy. Simple Facebook-style tooltip plugin for jQuery. # 30th December 2009, 6:21 pm

The Dangers of Clickjacking with Facebook. theharmonyguy compiled a list of actions that can be triggered on Facebook by a single click, and hence are vulnerable to clickjacking attacks. The list includes authorising malicious applications, posting links to profiles, sending friend requests and sending messages to other users. Why don’t Facebook include frame busting JavaScript on every page? # 23rd December 2009, 10:20 am

New Facebook clickjacking attack in the wild. I’m not sure why Facebook don’t use frame-busting JavaScript to avoid this kind of thing. The attack is pretty crafty—a Facebook page is positioned with everything obscured bar part of the blue “share this” button, and a fake “Human Test” asks the user to find and click the blue button to continue. # 22nd December 2009, 6:52 pm

FT.com: The rise and fall of MySpace (via) Lots of stuff about the internal politics at News Corporation. Of particular interest: MySpace have to take feature proposals to News Corp for approval. Meanwhile, Facebook are leading the industry in their use of A/B testing to figure out exactly what features their users will respond well to. # 5th December 2009, 5:09 pm

Facebook and MySpace security: backdoor wide open, millions of accounts exploitable (via) Amazingly, both services had wide open holes in their crossdomain.xml files. Facebook were serving allow-access-from-domain=“*” in the crossdomain.xml file on one of their subdomains (a subdomain that still had access to the user’s profile information) while MySpace were opting in farm.sproutbuilder.com, a service which allowed anyone to upload arbitrary SWF files. # 5th November 2009, 9:47 am

Facebook Hacked By 4chan, Accounts Compromised. It wasn’t Facebook that got hacked: 4chan members got hold of a list of usernames and passwords from an insecure Christian dating site and started using them to raise complete hell. Yet another demonstration that storing your user’s passwords in the clear is extremely irresponsible, and also a handy reminder that regular users who “don’t have anything worth securing” actually have a great deal to lose if their password gets out. # 23rd August 2009, 10:02 am

Up and running with Cassandra. Twitter are beginning to use Cassandra, the open source branch of Facebook’s BigTable-like non-relational database. Evan Weaver explains how to get started with it, but warns that it’s not yet a good idea to trust data to it without having a full backup in an unrelated storage engine. # 7th July 2009, 11:18 am

Exclusive: The Future of Facebook Usernames. I have to admit I was planning to just let Facebook get on with it, assuming that the OpenID provider part would show up of its own accord—but maybe I should write a thoughtful and persuasive essay about it after all. # 11th June 2009, 9:46 am

Streams, affordances, Facebook, and rounding errors. I asked Kellan about scaling activity streams the other day. Here he suggests the best technique is not to promise a perfect stream (like Twitter does)—Facebook used to get away with 80% loss of update messages, but their new redesign has changed the contract with their users. # 19th March 2009, 2:02 pm

Parallel merge sort in Erlang. Thoughts on an Erlang-y way of implementing a combined activity stream (e.g. Facebook and Twitter). Activity streams are a Really Hard Problem—as far as I know there’s no best practise for implementing them yet. # 15th March 2009, 1:36 pm

Plaxo sees 92% success rate with OpenID/OAuth hybrid method. Really wish I could have been at the OpenID UX Summit hosted by Facebook yesterday—sounds like an awful lot of important problems are being solved. # 11th February 2009, 5:20 pm

Four reasons why public Facebook status updates won’t kill Twitter. Mike Butcher highlights the importance of “follow” rather than “friend” in social software. # 9th February 2009, 7:04 pm

Integrating Facebook Connect with Django in 15 minutes. Django authentication middleware that calls the Facebook REST API using a cookie set by Facebook Connect and checks if that person is your Facebook friend. Despite most of the magic happening on the server you still need Facebook’s JavaScript to set that cookie in the first place. # 17th December 2008, 1:18 pm