Global spam mail volumes have been reduced by about a third following the takedown of the Rustock botnet, according to Symantec, with the number expected to decrease further after Trend Micro announced it had also crippled a Zeus botnet server.
Symantec's monthly MessageLabs Intelligence report, released on Thursday, showed that spam volume fell by 33.6 percent between 15-17 March, following legal action bringing down the command-and-control machines running the Rustock botnet by Microsoft and US law enforcement agencies.
Rustock was previously responsible sending approximately 44.1 billion email messages a day and accounted for 47.5 percent of all spam mails by the end of 2010, the report noted.
For more on this ZDNet UK-selected story, see Symantec: Global spam mail down by a third on ZDNet Asia.
Get the latest technology news and analysis, blogs and reviews delivered directly to your inbox with ZDNet UK's newsletters.