Drop in “Canadian pharmacy” spam

First it was Spamit, and now Rustock. Together, they once accounted for most of the spam reputedly sent from so-called “Canadian pharmacies,” but the demise of the former combined with the latter's apparent change of strategy, have signaled an end to the flow of come-ons for discount Canadian Viagra.

The January MessageLabs Intelligence report noted that spam levels had reached the lowest point in two years – 78.6 percent of all email traffic – largely because Rustock stopped sending spam for a two-week period beginning Christmas Day. After reaching a high of 85 percent of spam last May, pharmaceutical-related spam represented just 59.1 percent in January, according to MessageLabs.

The largest spam-emitting botnet in 2010, Rustock was one of two main sources of “Canadian pharmacy” emails. The other, Spamit, ceased operation in October.

By early January, the spam was flowing from Rustock again, and while its focus remained on pharmaceutical products, the sources are more generic.

“The spammers have shifted to other brands,” says Paul Wood of Symantec.