3 ms·

> The difference, I think, between POODLE and BEAST is that BEAST needed not just blockwise "chosen-boundary" control over plaintext, but also a continuous chan

> The difference, I think, between POODLE and BEAST is that BEAST needed not just blockwise "chosen-boundary" control over plaintext, but also a continuous channel that would provide the client with fine-grained control over the first N bytes of each request. It didn't work (IIRC) with vanilla Javascript. Sure you have control over the first N bytes. Look at the request-line: "GET /hello/world/this/is/my/url HTTP/1.1". Sure, you don't control the spaces, but you can assume any practical implementation uses a single space character. Combine that with control over the method (with XHR or statically through <form> or <img>) and the path, you're in business. AIUI, the JS PoC took a fair bit of trial-and-error to find the right value of N, but all these attacks require a fair number of requests anyway, so it's not really significant.

cryptbe 12y ago
> Sure you have control over the first N bytes. Look at the request-line: "GET /hello/world/this/is/my/url HTTP/1.1". Sure, you don't control the spaces, but you can assume any practical implementation uses a single space character. Combine that with control over the method (with XHR or statically through <form> or <img>) and the path, you're in business. tptacek is right. To make BEAST work we had to control _all_ the bytes of the very first block. We tried very hard to make it work with Javascript, but we couldn't. Java applet (and maybe Flash) was the only tool that gave us that kind of control.