Already a subscriber? Make sure to log into your account before viewing this content. You can access your account by hitting the “login” button on the top right corner. Still unable to see the content after signing in? Make sure your card on file is up-to-date.

According to the Cybersecurity and Infrastructure Security Agency (CISA), hackers with ties to Russia accessed communications between US federal agencies and Microsoft.

The hackers, identified by CISA as the Russian state-sponsored group “Midnight Blizzard,” have targeted federal systems using sophisticated methods. In a directive issued by CISA, the agency seeks to understand the full scope of the compromised data and assess the potential security repercussions.

CISA Director Jen Easterly commented on the situation, stating, “For several years, the US government has documented malicious cyber activity as a standard part of the Russian playbook; this latest compromise of Microsoft adds to their long list. We will continue efforts in collaboration with our federal government and private sector partners to protect and defend our systems from such threat activity.”

Microsoft has also acknowledged attempts by Midnight Blizzard to infiltrate its systems. In March, the company revealed that the group had used information from previous breaches to try and gain further unauthorized access. Microsoft first noticed these intrusion attempts in January when it detected a nation-state attack that compromised a small fraction of corporate email accounts.