(Bloomberg) The online attack that disrupted MGM Resorts International resorts and casinos across the country began with a social engineering breach of the company’s information technology help desk, according to a cybersecurity executive familiar with the investigation.Most Read from BloombergMGM Resorts Hackers Broke In After Tricking IT Service DeskUS, Chinese Officials Meet in Malta in Bid to Keep Channels OpenHouse Republicans Prepare to Turn US Government Shutdown Into Immigration Clash