I use my on line banking as little as possible after I got a virus that intercepted my on line banking, it pulled up a page identical to the banks log in page, except it had an extra box for all the memorial data numbers instead of asking for 3 number of 10.
I got as far as entering my account number and password, but telephoned the bank about the third box for memorial data which I did not enter, and was told it was a virus. This was despite keeping my anti-virus up to date. Scary stuff and very clever.