During the Rustock botnet’s weeks after Microsoft’s dramatic take down, Australia remained one of its most deeply penetrated nations, according to an analysis by Microsoft’s Digital Crimes Unit.
Microsoft researchers were able assess the botnet’s impact across the world after they successfully reverse-engineered the algorithms it had used to generate its domain names, prior to its March take down. The researchers then registered the domains that would have been taken by Rustock and reassigned its traffic to Microsoft-controlled “sinkhole” servers.
The domains that Microsoft preempted would have been relied upon if Rustock’s command and control servers were unavailable. This occurred after the server raids in March, offering Microsoft an opportunity to measure the botnet’s scale and distribution
Infected computers in the US by far generated the most sinkhole traffic at 55 million hits over the week after its takedown, followed by France and Turkey with 13 million hits a piece, Canada with 11.4 million, and India and Brazil with 7 million each.
Australia, with notably fewer computers than all major victims except Canada, fell into the next category, which triggered between 2 to 10 million hits. In contrast, countries with many more computers such as China clocked up just 421,000 hits.
The drop in pings from Australian computers to Microsoft’s sinkhole servers were also slower to respond to Microsoft’s take down in March this year.
While Microsoft observed a larger than 60 per cent fall in the number of Asian and Europen IP addresses contacting its Rustock sinkhole, the number for Australia dropped between 30 to 40 per cent, according to Microsoft’s Malware Protection Center figures. Australian reductions were similar to figures recorded for the US.
Despite Microsoft's victory in stifling the spam network, its efforts to find those behind the botnet have not yet produced results. Microsoft has named the suspects, placed advertisements in Moscow newspapers and established a www.noticeofpleadings.com site as part of the legal efforts which allowed it to seize the botnet's command and control servers.
In April Microsoft named suspects Vladimir Alexandrovich Shergin and Dmitri A. Sergeev as suspects in its most recent notice of pleadings filing [PDF].