Pharmaceutical spam is now making up 75 per cent of all spam.

According to the TRACElabs report from Marshal8e6, January to June 2009, there was a 60 per cent increase in spam volumes, with spam now representing 90 per cent of all inbound email.

The report also claimed that the Rustock botnet emerged as the dominant force in spam output in 2009 and is responsible for more than 40 per cent of all spam sent so far this year. Scareware applications, such as fake anti-virus, have risen to a level never seen before with hundreds of variants now released on the internet.

In addition to the rise in spam volumes, Marshal8e6 TRACElabs has observed a wave of legitimate websites being compromised by hackers and serving up spam to unsuspecting visitors. According to the report, roughly 70 per cent of the websites hosting malicious content today are legitimate sites that have been hacked.

Bradley Anstis, director of technology strategy at Marshal8e6, said: “While legal entities and the security community have made strides in combating hosting servers that support malicious botnets, we've seen a number of new tactics from the spammers themselves taking hold in the first half of 2009.

“The rise of the Rustock botnet feeds the growth of blended threats. Rustock typically uses HTML templates from legitimate newsletters and inserts, or blends in, its own images and URL links. This helps give Rustock spam the appearance of professional, legitimate email which tricks recipients into clicking on the links or buying the advertised products.”