Re-transmittal of Cybersecurity and Infrastructure Security Agency (CISA)/Federal Bureau of
Investigation (FBI) Alert AA21-131A dated May 11, 2021: “The Cybersecurity and
Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) are aware
of a ransomware attack affecting a critical infrastructure (CI) entity—a pipeline company—in the
United States. CISA and FBI urge CI asset owners and operators to adopt a heightened state of
awareness and implement the recommendations listed in the Mitigations section of this Joint
Cybersecurity Advisory, including implementing robust network segmentation between IT and
OT networks; regularly testing manual controls; and ensuring that backups are implemented,
regularly tested, and isolated from network connections.” The full text of this Joint Cybersecurity
Advisory is available at https://go.usa.gov/xHsxf.

For any questions about this Alert, please utilize the contact info within the CISA Alert at the
above URL.