Bugtraq mailing list archives

Re: houghts and a possible solution on homograph attacks


From: Sven Putteneers <svennieboy () linux be>
Date: Tue, 8 Mar 2005 19:50:36 +0100

On Mon,  7 Mar 2005 at 15:05:51 -0500, Scovetta, Michael V(Michael.Scovetta () ca com) wrote:

<plug>
I've released a "fix" for the IDN vulnerability
(www.scovettalabs.com/advisory/SCL-2005.002.txt) that basically prevents
you from going to *any* domain that has a non-[\-A-Z0-9] character in
it. For me, it's fine, since I'll likely never need to go to an IDN
domain.
</plug>

If this patch would be widely used, we'd lose the all the advantages
associated with IDN.
Maybe it's better to attack this problem on the browser side and have a
configuration switch to enable or disable IDN. We could disable it as a
"reasonable default", but those who need it, could enable it.
Upon enabling the option, a warning dialog could pop up that warns the
user about the security problems associated with IDN ("don't enable this
unless you know what you're doing" stuff).

That way the majority of the users would be safe from IDN attacks
(phishing comes to mind) and those who really want IDN would have to
click through a warning dialog telling them why enabling it may not be
such a good idea.

Just my €0.02,
Sven


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