Sony Pictures was so crippled by last month’s cyberattacks that it was forced to create a phone tree to help employees update one another, person-to-person, about the hack. Sony CEO Michael Lynton said the studio coped with the security breach by using personal cellphones, Gmail accounts, notepads, and also reviving old company BlackBerrys, which operate on a different server. The payroll department even revived an old machine to cut paychecks manually. Hacking group Guardians of Peace stole troves of both company and personal data, including employee salaries and Social Security numbers, as well as leaked movies, internal documents, and emails late last month. The FBI has previously said North Korea was behind the attack, but security experts are investigating whether the company was compromised by former employees.