Simon Willison’s Weblog

Blogmarks tagged javascript, framebusting

Filters: Type: blogmark × javascript × framebusting ×

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

Twitter Don’t Click Exploit. Someone ran a successful ClickJacking exploit against Twitter users, using a transparent iframe holding the Twitter homepage with a status message fed in by a query string parameter. Thiss will definitely help raise awareness of ClickJacking! Twitter has now added framebusting JavaScript to prevent the exploit. # 12th February 2009, 7:56 pm

Frame-Busting Gadgets. I’ve always been slightly suspicious of the Google Gadgets / OpenSocial idea of sandboxing untrusted third party content in an iframe. Sure enough, it turns out iframe busting scripts work in Gadgets, meaning a seemingly harmless gadget could potentially launch a phishing attack. # 17th September 2008, 11:23 pm