Security experts say that many of these subdomain hosting companies, which typically offer free domain-name registration, have opened up a lawless frontier on the Internet where nearly anything goes. "There's a huge amount of abuse going on on those subdomains," said Roel Schouwenberg, a researcher with security vendor Kaspersky Lab. "The bad guys select whichever domain is cheapest and most reliable," he added. "Some of these domain owners are extremely slow in responding to abuse issues."
Scammers had used a series of ingenious tricks to game Google's image search feature and spread the Mac Defender malware using bulk subdomains, said Sean Sullivan, a security adviser with F-Secure. Sullivan's company automatically blocks the ce.ms, cu.cc, cw.cm, cx.cc, rr.nu, vv.cc, and cz.cc domains with its security software, he added.
In June, Google blocked a number of bulk subdomain sites from its search index, saying that many of them had been used by criminals. "In some cases our malware scanners have found more than 50,000 malware domains from a single bulk provider," Google wrote in a blog post announcing the decision.
Reached Tuesday, Piatti was unable to comment for this story. " I would be glad to give you my side of the story, but I feel that I should hire a lawyer first," he said in an email.