Following takedowns of the Gameover Zeus, Ramnit and Shylock operations, Dyre infections surged and attacks became more aggressive, making it the most dangerous financial Trojan, Symantec said in a statement.
Dyre is a sophisticated piece of malware that targets Windows computers and can steal banking and other credentials.
It is capable of hijacking all three major web browsers -- Internet Explorer, Chrome and Firefox -- to intercept banking credentials.
Globally, targets also include users of electronic payment services and HR-related websites, it added.
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Symantec said financial gain is the primary motivation, but Dyre is often used to download additional malware onto a victim's machine and add them to a botnet.
"Based on the activity observed, the attackers adhere to a five-day work week during the UTC +2 or UTC +3 time zone, suggesting they operate out of eastern Europe or Russia," Symantec said.