COMMAND
WAP
SYSTEMS AFFECTED
WAP gateways
PROBLEM
'Gus' found following. 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 limited testing 3 of the 4 gateways used by UK mobile
operators are vulnerable. Given this ratio one would expect this
to be a global issue.
A browser-based testing tool for this issue is available at
http://wap.z-y-g-o.com/
along with other wireless security information.
SOLUTION
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)
Sprint PCS's WAP gateway does not give a detailed error message,
but does not allow the connection if the root certificate is not
a trusted root CA.