The California Department of Insurance reported that the 2015 Anthem breach was the result of a nation-state attack.
An examination team from CrowdStrike determined that the attacker responsible for the breach was acting on behalf of a foreign government, according to Anthem examination report, which didn't identify the government in question.
The purpose of the examinations was to assess Anthems cybersecurity preparedness prior to the breach as will as its breach response, and the adequacy of measures taken to mitigate harm and to identify the threat actors responsible for the incident.
The breach was discovered by the insurance company on January 27, 2015, and was announced by the company the following month. The breach compromised 78.8 million consumer records including those of at least 12 million minors. A separate investigation conducted by ThreatConnect found that the cyberespionage group Axiom may have been connected to the incident.