The compromising of information on almost 40 million RSA security tokens, which protect sensitive military and financial networks, was a major cyber attack. (MICHAEL CARONNA)

“We incurred an accrued cost associated with investigating the attack, hardening our systems and working with customers to implement our remediation programs,” said EMC’s executive vice president David Goluden.

EMC spent the $66 million on transaction monitoring for its corporate customers who worried that their RSA security tokens — long considered the gold-standard for protecting sensitive data — had been compromised in the attack. EMC also offered replacements to any company that requested them.

EMC also revealed some more information about the attack itself, saying that it alerted customers within hours of the intrusion and suspects that the company was targeted for information on its defense and government agencies, not for financial information.

The RSA breach is believed to have led to an attempted attack on defense contractor Lockheed Martin. EMC said nothing about who might have been responsible for the attack.