g1smd - 7:50 pm on Jan 10, 2012 (gmt 0)
You should ensure that
AcceptPathInfo is Off.
You should not be redirecting the duff URL requests. Doing that creates infinite URL space on your site. You should return 410 Gone or similar.
Be aware that RegEx patterns with a leading (.*) sub-pattern or multiple (.*) sub-patterns are ambiguous and very very inefficient. You should use something else.