A variant of
phishing involves subverting an
Internet access point, often used for
mobile computing.
Malware can
route user requests for
bank websites into a phisher's
private network, with fake
bank websites (pharming). The user can have a “mobile
password” at the
bank. When she connects from an access point, she sends a hash, found from the
password, starting at some position in it. The bank returns a hash, found from the same
password, starting at another position in it. Each can verify the other. We protect both from a
man in the middle attack. By hashing a
web page and the mobile password, and inserting the hash into the page that is sent, the recipient can verify that the page is untampered. We use an anonymizer, external to the access point. A user pre-establishes a password with the anonymizer. At the access point, she and the anonymizer use a zero knowledge protocol to verify each other, based on the password. Then, the password encrypts communication between them. From the anonymizer, she logins elsewhere. The anonymizer is our man in the middle, to defeat a
man in the middle attack. W extend earlier antiphishing methods, to
attack pharms for non-existent banks, or that are unauthorized websites for actual companies. We show how to use a plug-in to let websites share several two factor implementations. This reduces the cost and inconvenience to consumers, who might otherwise have to carry and use a different two factor gadget, for each of their bank accounts or other corporate websites that mandates the usage of two factor
authentication. By expanding the scope of two factor usage, we improve the security of e-commerce, without having to use a
public key infrastructure.