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Digest authentication: auth-int susceptible to DOS attacks?

From: Sam Idicula <sam_idicula@hotmail.com>
Date: Mon, 02 May 2005 18:51:51 -0500
Message-ID: <BAY18-F194C0D7275D2045FC87A3E90270@phx.gbl>
To: www-talk@w3.org


I have a question about the auth-int option of digest authentication:

Since the authentication check and the integrity check can both be done only
after reading the entire request, I'm assuming that the server needs to
buffer up the request body. Doesnt this open the door for an attacker to
flood a server with a large request (like a PUT with a 200MB body)?  Since
the request is large and server needs to buffer the request, this allows the
attacker to cause a lot of disk-write's on the server and consume disk space

The server can, of course, put limits on the size of the request body but
this would limit even legitimate users. For example, if the server limits it
to 64K, a legitimate user cannot store a file > 64K using a PUT request.

Does anybody know what is the standard/recommended solution to this problem?

Received on Tuesday, 3 May 2005 02:31:48 UTC

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