U.S. and allies warn of attacks from Iran-linked actors targeting critical infrastructure through brute-force attacks in a year-long campaign.Intelligence and cybersecurity agencies from the U.S., Australia, and Canada warn about a year-long campaign carried out by Iran-linked threat actors.The attackers targeted organizations in healthcare, government, IT, engineering, and energy sectors.The attackers used brute-force attacks, password spraying, and multi-factor authentication (MFA) prompt bombing techniques.