That's a demonstration I would like to see. As in, someone actually deducing it from the returned headers of a system they otherwise have no visibility to; rather than a just a theoretical speculation that it might be possible.
On the security list, someone posted (1) a short perl program which created a hash with 28 shortish random word keys (i.e. those matching /[a-z]{2,12}/), and then printed those keys to stdout in unsorted order; (2) a C program, which given as input that list of keys, in 785 CPU seconds was able to completely determine the random hash seed of that perl process.

Given that it is common for web apps to output headers or parameters or other things which are, or are derived from, unsorted hash keys, then put those two together and you get remote seed determination. I don't think anyone went as far as actually demonstrating it against a web server.

Dave.

In reply to Re^8: Our perl/xs/c app is 30% slower with 64bit 5.24.0, than with 32bit 5.8.9. Why? by dave_the_m
in thread Our perl/xs/c app is 30% slower with 64bit 5.24.0, than with 32bit 5.8.9. Why? by Anonymous Monk

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