A report says that hackers broke into Equifax's computer systems in March, giving them time to probe vulnerabilities and eventually gain access to the data of 143 million Americans. That's according to The Wall Street Journal, which cited a report from security firm FireEye sent to some Equifax customers including financial firms this week. The breach on March 10 came two days after security researchers at Cisco Systems warned of a flaw in an open-source software package called Apache Struts.