E-mails with exploitive headlines mentioning George Bush, Microsoft and Al Qaeda in their subject lines are part of a co-ordinated malicious spam campaign from criminals controlling the Rustock botnet.
The Marshal Trace security team says the large-scale campaign is designed to infect computers with malware and convert them into part of the Rustock botnet, and it is succeeding, says Marshal.
Over the past month, Rustock has grown to claim second place among the largest spam-producing botnets, behind only the Srizbi botnet.
Rustock has increased its share of global spam volumes from 10% in mid June to 21.5% last week, says Marshal's TRACE statistics.
Malicious spam, which is designed to infect computers with malware rather than promoting a product, leapt to an all-time high of almost 19% of spam last week.
In June 2008, malware spam surged to its previous highest level of 10%, up from 3% where it had been steady since February 2008.
Examples of the e-mail headers used in the Rustock spam campaign include
"Bush Down to 8 Friends on Myspace"
"Yahoo sold to Microsoft, record price"
"Al Qaeda Reports Declining Revenues in Fiscal '08"
"Martian Soil Fantastic for Growing Weed Says Nasa"
"Obama Is Anorexic Over-Exerciser"