"In coordination with government and industry partners, the Department of Homeland Security (DHS) Cybersecurity and Infrastructure Security Agency (CISA) is tracking a series of incidents involving Domain Name System (DNS) infrastructure tampering. CISA is aware of multiple executive branch agency domains that were impacted by the tampering campaign and has notified the agencies that maintain them. [...] To address the significant and imminent risks to agency information and information systems presented by this activity, this emergency directive requires the following near-term actions to mitigate risks from undiscovered tampering, enable agencies to prevent illegitimate DNS activity for their domains, and detect unauthorized certificates."
Department of Homeland Security. Cybersecurity and Infrastructure Security Agency: https://cyber.dhs.gov/