Infamous hacker group Anonymous has been suspected as the likely attacker, but the group has denied involvement. On Friday, members of Anonymous disclosed, in statements made to the Financial Times, that one or more members of the anarchic collective were involved in the takedown.
Evidence seems to suggest that the Anonymous members who left breadcrumbs of their exploit on PlayStation servers may have been operating as a small anti-Sony faction within the larger group. This would explain Anonymous's very public denials.
"An individual or handful of supporters of Anonymous’ well-publicised operation to disrupt Sony services – dubbed OpSony – went further than the rest of the free-speech campaigners expected when they broke into the electronics company’s network and stole account details, according to one person within the group," reads the account.
An Anonymous hacker going by the handle Kayla told the Financial Times, “If you say you are Anonymous, and do something as Anonymous, then Anonymous did it … Just because the rest of Anonymous might not agree with it, doesn’t mean Anonymous didn’t do it.”