🚀 go-pugleaf

sjmz@otter.hpl.hp.com (Stefek Zaba) writes:

> Maybe yes, maybe not; but I'm reminded of a classic password attack I heard
> about on (oneof (multics tops20)) a while back...
> [...] by repeated probes with your submitted
> password guess broken across a page boundary, arranging for the "far" page to
> be swapped out, and timing the return (remember, page faults cost *lots* of
> time in them thar days) you could reduce the number of probes from
> [alphabet_size ** passwd_length] to [alphabet_size * passwd_length].

If I'm remembering the same attack, it was easier to arrange to catch
memory-reference violations, and put your password up at the very top of
addressable memory.  The OS would give you the violation if your guess
was correct up to the edge of memory, and return failure if the guess
wasn't a proper prefix.

I think this was also a usable attack against Datapoint RMS systems.

-- 
Tom Fitzgerald   Wang Labs       fitz@wang.com   "I went to the universe today;
1-508-967-5278   Lowell MA, USA                   It was closed...."