According to security company Solutionary, Amazon's public cloud is the largest haven of malware spreaders in the US.

"Malware and, more specifically, its distributors are utilizing the technologies and services that make processes, application deployment and website creation easier. Now we have to maintain our focus not only on the most dangerous parts of the Web but also on the parts we expect to be more trustworthy," according to Rob Kraus, director of research in Solutionary's Security Engineering Research Team (SERT).

"Attackers are leveraging services like Amazon and GoDaddy by either buying services directly or by compromising legitimate domains," the report stated. "These providers are likely targets due to the transient nature of many of their users and the lack of formal hardening."

This isn't the first time such accusations have been made. Amazon came under criticism about what it held in its cloud. In July, 2011, security firm Kaspersky said that S3 storage service had been caught hosting the nasty SpyEye banking trojan.

The report also sheds some light on the effectiveness of todays AV programs. Malware samples gathered late last year were undetectable by at least 40 antivirus engines.