The Top Cyberattacks of March 2021

March 2021 saw a spate of high-impact attacks: a large-scale Microsoft Exchange Server compromise attributed to the Hafnium group that exploited four vulnerabilities and backdoored tens of thousands of organizations; ransomware outages affecting media (Nine Entertainment) and IoT vendor Sierra Wireless; and a phishing-driven data breach at the California State Controller exposing employee SSNs — illustrating active exploitation of vulnerabilities, targeted APT activity, and financially motivated ransomware/phishing campaigns across multiple industries.