Morgan Stanley experienced a very sensitive break-in to its network by the same China-based hackers who attacked Google Inc.’s computers more than one year ago, according to e-mails stolen from a cyber security company working for the bank. The emails from the Sacramento, California-based computer security firm HBGary Inc., which identify the first financial institution targeted in the series of attacks, said the bank considered details of the intrusion a closely guarded secret. They were hit hard by the real Aurora attacks, wrote a senior security engineer at HBGary, who said he read an internal Morgan Stanley report detailing the so-called Operation Aurora attacks. The nickname came from McAfee Inc., a cyber-security firm, which said the attacks occurred for about 6 months starting in June 2009 and marked a watershed moment in cyber security. The number of companies known to be hit in the attacks was initially estimated at 20 to 30 and now exceeds 200, said the senior vice president for Terremark Worldwide Inc., which provides information technology security services. The HBGary e-mails do not indicate what information may have been stolen from Morgan Stanley’s databanks or which of the world’s largest merger adviser’s multinational operations were targeted.