Starts off with your members starting to receive the auto emails from the VB software warning them of 5 strike attempts. The 1st few I thought nothing of and just reminded the members about choosing a good strong password for their account. But the numbers increased and increased stressing the members and me out at which point I was alerted to the problem. Then I saw that post over at vb.com and totally related to it.
I did for the 1st few times when I saw member IPs wonder whether they might have virus/malware on their PCs so asked them to check but then the numbers got so high it wasn't feasible anymore unless all their PCs were infected.