Meanwhile, Sony denied assertions by computer security expert Gene Spafford during a Congressional hearing Thursday that it had been running outdated versions of Web server software and had not been using a firewall on its servers. In a statement from Patrick Seybold, Sony's senior director, Corporate Communications and Social Media, that's expected to be published on Sony's PlayStation blog, the company was using updated software and had "multiple security measures in place." Here's the statement in full:
"The previous network for Sony Network Entertainment International and Sony Online Entertainment used servers that were patched and updated recently, and had multiple security measures in place, including firewalls."
Separately, Sony President Kaz Hirai sent a letter to Connecticut senator Richard Blumenthal containing a detailed timeline of the attack and Sony's response to it. The letter contains previously undisclosed details about the attack and the hardware Sony uses to run its gaming services.
The letter, which is embedded below, says that the systems involved use 130 servers and 50 distinct software programs. Sony first noticed the attack on April 19, when its network team discovered that several PlayStation Network servers had rebooted themselves unexpectedly. Four servers were immediately taken offline in order to figure out what was going on. By the next day, it was clear that another six had been attacked, and they were taken offline as well. By April 23, computer forensic teams confirmed that intruders had used what Sony describes as "very sophisticated and aggressive techniques to obtain unauthorized access to the servers and hide their presence from the system administrators" and had deleted log files showing the footprints of where in the system they had been. By April 24, Sony had hired three different computer security firms to investigate the attack.