Equifax Suffered a Hack Almost Five Months Earlier Than the Date It Disclosed

Bloomberg is reporting that Equifax, the credit reporting company that recently reported a cybersecurity incident impacting roughly 143 million U.S. consumers, learned about a breach of its computer systems in March -- almost five months before the date it has publicly disclosed. The company said the March breach was unrelated to the recent hack involving millions of U.S. consumers, but one of the people familiar with the situation said the breaches involve the same intruders. From the report: Equifax hired the security firm Mandiant on both occasions and may have believed it had the initial breach under control, only to have to bring the investigators back when it detected suspicious activity again on July 29, two of the people said. Equifax's hiring of Mandiant the first time was unrelated to the July 29 incident, the company spokesperson said. The revelation of a March breach will complicate the company's efforts to explain a series of unusual stock sales by Equifax executives. If it's shown that those executives did so with the knowledge that either or both breaches could damage the company, they could be vulnerable to charges of insider trading. The U.S. Justice Department has opened a criminal investigation into the stock sales, according to people familiar with the probe.

In early March, they said, Equifax began notifying a small number of outsiders and banking customers that it had suffered a breach and was bringing in a security firm to help investigate. The company's outside counsel, Atlanta-based law firm King & Spalding, first engaged Mandiant at about that time. While it's not clear how long the Mandiant and Equifax security teams conducted that probe, one person said there are indications it began to wrap up in May. Equifax has yet to disclose that March breach to the public.