Hmm? What is your sister's computer?
Using Backtrack4 with either Airpwn, Airsnarf or even WifiZoo, one can emulate an AP and "catch" all manner of people trying to login to a web portal spoofing itself as a CC gateway. If you don't get the CC, you will get the username and password of local APs perhaps? A paypal link is like Gold, since you can use triangulation just as deftly to protect yourself, cleaning out the funds from a group of accounts that point to each other.
I set up a Nomadix in Produce Row in Portand Oregon, which had a cc forward for all port 80 traffic attempts to
11wireless.com for the CC details.
I have used ASU's systems which were HORRIBLE!
The OS version might be important also, but only with regards to the software acting as AP?
A radius server (or ICA certificate Auth server in $M world) can handle the CC authentication/forwarding and seeming, or any software setup to do so.
The driver to access the "modem, set into AP mode" is connected to the application, connected to the auth server/process.
Bottom line is:
WE NEED MORE PROECT EQUIPMENT SPECIFICATIONS to answer questions?