They have also come up with strong evidence that confirms claims the DDoS rampage that brought down Twitter and hit Facebook, Google's YouTube and LiveJournal, were caused by attacks .

But they have yet to nail down exactly who was behind the attacks, how they were conducted, and from where.

Twitter, meanwhile, admitted that the attacks were "geopolitical in motivation."

"This was a very targeted attack, and what the research shows is that it was aimed at one particular person, and that person's accounts on Twitter, Facebook, YouTube and LiveJournal," said Dave Marcus, director of security research at antivirus vendor McAfee.

McAfee has identified six separate DDoS attacks against various accounts registered to a user pegged as "Cyxymu," as well as a simultaneous spam e-mail campaign aimed at Cyxymu's Gmail account.