Important to note that these attacks are occurring BEFORE transmission. Therefore, the SSL tunnel between you and your bank (signified by the little lock on your browser) is meaningless as your information is compromised as it is entered on the form. The information is then sent by malware back to the harvesters who sell your information to the highest bidder. Preventing infection, detecting and removing the malware, and blocking egress communications with a firewall are the best prevention mechanisms. Also, keeping an eye on your credit is important.