Many WAP gateways do not properly check SSL certificates

[Gus <angus () z-y-g-o com>]

In a browser environment, when you connect to an site using SSL/TLS your
browser automatically checks that the domain part of the URL matches the
domain in the X.509 certificate that the HTTPS server presents when you
connect to it.

Since SSL certificates are tamper-evident as the cryptographic signature
is checked against the "root" certificates of the large CAs (Thawte,
Verisign, Global Trust etc.) this check gives assurance that the
requesting party is connected to the right host - i.e. you are safe from a
man-in-the-middle attack.

It appears that most WAP gateways do not carry out this check, or if they
do, no information about mismatches is passed back to the handset. In my
limited testing 3 of the 4 gateways used by UK mobile operators are
vulnerable. Given this ratio I would expect this to be a global issue.



CMG is aware of the problem and will be issuing a patch with the next
upgrade. (Vodafone UK)

Openwave (Phone.com) is shipped vulnerable by default but can be fixed by
configuration interface. (one2one, Virgin UK, BTCellnet/Genie)

Nokia on HP/UX is not vulnerable. (Orange UK, Cingular USA)



A browser-based testing tool for this issue is available at
http://wap.z-y-g-o.com/ along with other wireless security information.

Thanks to Rodney Tanner <RTanner () PRTM com> for initially bringing this
issue to to my attention.


Regards,
        _Gus



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