A cyber attack at Sony Pictures in 2014 resulted in the release of sensitive internal documents, the eventual ouster of the top executive and multimillion-dollar settlements with employees. Hackers struck again in 2016, this time targeting a post-production vendor of Netflix with a threat to leak unreleased shows if their ransom demand wasn’t met. The latest attack is against HBO, and hackers have upped the ante with a demand for millions of dollars to stop the leak of internal emails, passwords, salary information, stars’ phone numbers and scripts for Game of Thrones . Experts say the increasing threat of these sophisticated cyber crimes should force Hollywood to take serious stock of its internal security measures.…