Companies across the globe have reported that they have been struck by a major ransomware cyber-attack. The virus, the source of which is not yet known, freezes the user's computer until an untraceable ransom is paid in the digital Bitcoin currency.Ukrainian firms, including the state power company and Kiev's main airport, were among the first to report issues. The Shipping Ministry has confirmed that one terminal at Jawaharlal Nehru Port Trust (JNPT) in Mumbai has been affected due to ransomware cyber attack. The Ministry and JNPT are taking steps to ensure minimum disturbance to trade, transporters and more importantly local citizens. The Government today said it has initiated proactive measures and is keeping a close vigil on the ransomware attack.