[deathanatos]

Actually, I think there are cases where people have patched closed source software. Binary patches are possible, just harder to write. (Not trying to say you're wrong: it's definitely easier if one has the source. Only that some humans are both determined and skilled, and some incredible stuff comes from that combination.)

IIRC, there was a flaw in Flash patched in this manner; it was using memcpy(), which requires the source and destination regions to not overlap, but, they did. In this case, it's fairly simple: one just needs to call memmove(), which conveniently takes the same args in the same order.

(IIRC, there was a lot of consternation getting Adobe to fix that properly, given how obvious the bug was.)