Routers in four countries have been hacked for up to a year, cybersecurity firm FireEye said on Tuesday, including some used by governments and major industries.

FireEye’s forensic team, Mandiant, found that 14 routers owned by Cisco in the Ukraine, the Philippines, Mexico and India were penetrated and infected with malware that FireEye named “SYNful Knock.” Cisco described it as “a type of persistent malware that allows an attacker to gain control of an affected device.”