Há tanto tempo que não se via uma invasão de 1M PCs em um dia...
Conficker worm spikes, infects 1.1 million PCs in less than 24 hours
"It has been over a month since we heard much about Conficker, but the worm has reappeared with a vengeance over the past seven days. According to Finnish security company F-Secure, more than one million PCs have been infected with the worm (also known as Kido or Downadup) in the past 24 hours, with a total of 3.52 million machines infected worldwide. According to F-Secure, that 3.52 million is a conservative estimate."
MSRT Released Today Addressing Conficker and Banload
fonte: Microsoft® Malware Protection Center