Re: Weak iv filtering

usually, most of the wireless drivers out there just tell the card that the=
y
want to send a certain packet across the wireless network. then the card is
in charge of choosing a suitable iv, encrypting the packet with the static
key that's previously set on the card, calculating checksums and such, and
then sending off the packet.. in this case, it'd be up to the firmware to
choose an iv that isn't weak.

prism chipsets allow you to implement the encryption/decryption in the
driver however (which most drivers don=B9t use). in which case the driver is
in charge of doing all of the wep encryption on the packet (including
choosing the iv).

basically to answer your question, almost all of the time the iv is chosen
by the firmware, however there are ways to code a driver for some chipsets
that let the driver handle what iv's you're sending your wep'ed data with.
as far as hardware vendors that perform this in their firmware, I don't
know..

-h1kari


On 3/29/03 11:06, "Tye F. Hammerle" <[email protected]> wrote:

> Where is weak iv filtering performed? in the card's firmware or the
> systems driver for the card? or does it depend on the vendor? Logic
> would seem to say in the firmware but I suppose it could go either way.
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> Also seems to me that if only one side of a connection does weak iv
> filtering you will still see unfiltered weak iv's from the non-filtering
> side. It would of course take longer to aquire enough iv's to crack the
> key but this setup would be more vulnerable than one doing weak iv
> filtering on both sides.
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> Does anyone know with relative certainty of a vendor currently shipping
> 802.11b product that does not do weak iv filtering?
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> Cisco does weak iv filtering. I have received word from D-Link that they
> do not currently do weak iv filtering. (I have a low level of confidence
> in the accuracy of their answer though. I wasn't able to speak directly
> with anyone who seemed knowledgable enough to know.)
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> Tye
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