Simon Willison’s Weblog

Items tagged security, framebusting, iframes

Filters: security × framebusting × iframes ×


Busting frame busting: a study of clickjacking vulnerabilities at popular sites (via) Fascinating and highly readable security paper from the Stanford Web Security Research group. Clickjacking can be mitigated using framebusting techniques, but it turns out that almost all of those techniques can be broken in various ways. Fun examples include double-nesting iframes so that the framebusting script overwrites the top-level frame rather than the whole window, and a devious attack against the IE and Chrome XSS filters which tricks them in to deleting the framebusting JavaScript by reflecting portions of it in the framed page’s URL. The authors suggest a new framebusting snippet that should be more effective, but sadly it relies on blanking out the whole page in CSS and making it visible again in JavaScript, making it inaccessible to browsers with JavaScript disabled. # 24th May 2010, 11:40 am

FB App Canvas Pages: I Think I’d Use IFrames. Facebook’s Charlie Cheever explains the difference between FBML canvas pages, iframe pages and XFBML when building Facebook apps. I’m always surprised at APIs that load untrusted content in an iframe, as it seems like an invitation for frame-busting phishing attacks. # 2nd October 2008, 2:39 pm