“Activities in the last month showed the strength of the Pushdo botnet, which is a clear indicator that the socially-engineered mass e-card approach continues to gain traction,” said Derek Manky, security research engineer for Fortinet.
“Consumers should be reminded that legitimate e-cards are not generally sent as attachments, but rather as links to a hosting Web site. And as a rule of thumb, we should all avoid opening attachments from unsolicited emails.”
The security vendor said it was most interesting that the botnet was most active on Sundays when users are at rest and away from their offices.
It was recently reported that the Pushdo botnet was also responsible for targeting customers of Google AdWords in a phishing scam last month that urged recipients to re-activate their accounts.
Meanwhile, Fortinet's fast moving threat for March was the parasitic file infector, Virut.A, which landed in fourth place from its 29th position in the previous edition of this report.
Furthermore, MyTob and MyDoom families continue consistent activity with four variants in the Top Ten list.