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From Dean Gaudet <dgau...@arctic.org>
Subject Re: yet another DoS attack (was Re: Bug in URI parsing)
Date Mon, 05 Jan 1998 19:36:33 GMT
I should also add that you can easily set yourself up for similar DoS
attacks with 1.3 using "allow from domain" or "deny from domain".  In that
case you need control of your reverse DNS, and you simply point your
reverse at some bogus address.  Then the server will chunk when it tries
to double-reverse your address.  So you attack by requesting lots of URLs
that require double-reverse.

In general though the folks with control over reverse DNS have much better
things to do with their time.  So this maybe isn't as big an issue.  And
it's an attack against tcpwrappers as well so we're not alone on this one. 
Forward DNS on the other hand is in the hands of lots of devious folks.

Oh yeah, also due to negative DNS caching, to set up a full attack against
check_fulluri() you may need several hundred bogus DNS records.  But that
doesn't seem to be necessary against my bind-8.1.1 server, I get a 63s
timeout on every request to dne.arctic.org.

Dean


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