The hackers first registered the domain "opmsecurity.org" to "Steve Rogers, a.k.a. 'Captain America,'" in April 2014, according to investigators on the House Oversight Committee. The name was later used as a "command and control" domain to direct malware in the agency's systems.
A second domain, "opmlearning.org," was registered to Tony Stark, Iron Man's alter ego, in July 2014. Report authors found it was Iron Man who ultimately completed the mission after OPM officials detected Captain America and believed they had removed him through an operation dubbed "the Big Bang."