BancoEstado, one of Chile's three biggest banks, was forced to shut down all branches on Monday following a ransomware attack that took place over the weekend.
"Our branches will not be operational and will remain closed today," the bank said in a statement published on its Twitter account on Monday.
Details about the attack have not been made public, but a source close to the investigation told ZDNet that the bank's internal network was infected with the REvil (Sodinokibi) ransomware.
The incident is currently being investigated as having originated from a malicious Office document received and opened by an employee. The malicious Office file is believed to have installed a backdoor on the bank's network.
Investigators believe that on the night between Friday and Saturday, hackers used this backdoor to access the bank's network and install ransomware.