Simon Willison’s Weblog

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