Pierluigi Paganini September 07, 2020

Chilean bank BancoEstado, one of the country’s biggest banks, was forced to shut down all branches following a ransomware attack.

Chilean bank BancoEstado, one of the country’s biggest banks, was hit with a ransomware attack that forced its branches to remain closed since September 7.

The ransomware encrypted most of the company servers and workstations.

The attack took place over the weekend, the closure of the BancoEstado breaches was announced by the bank through its Twitter account.

The bank disclosed the attack on Sunday via Twitter and decided to keep branches closed to investigate the incident and recover its systems.

“Our branches will not be operational and will remain closed today,” reads the statement published on Twitter.

The bank launched an investigation into the incident and reported it to Chilean police.

The Chilean CSIRT also issued a cyber-security alert warning about a ransomware campaign targeting the private sector.

According to ZDNet that cited a source close to the investigation, the Chilean bank was attacked by the REvil ransomware operators, but at the time of writing the BancoEstado’s data have yet to be published on the gang’s leak site.

“Investigators believe that on the night between Friday and Saturday, hackers used this backdoor to access the bank’s network and install ransomware.” reported ZDNet. “Bank employees working weekend shifts discovered the attack when they couldn’t access their work files on Saturday.”

Threat actors used the malicious Office file to deliver a backdoor on the bank’s infrastructure and use it as the entry point. It seems that the attack vector was a series of spam messages using weaponized Office documents.

According to the bank, its website, the banking portal, mobile apps, and the ATM network were not impacted thanks to a good design of the BancoEstado’s infrastructure.

The REvil ransomware gang is one of the most active groups, in the past, the operators have targeted Pulse Secure and Citrix VPN and enterprise gateway systems as entry points.

The list of victims is long and includes Telecom Argentina, Sri Lanka Telecom, Valley Health Systems, Australian firm Lion, Brown-Forman, the electrical energy company Light S.A., and Elexon electrical middleman.

In June 2018, North Korea-linked hackers hit another bank in Chile, the Banco de Chile infecting its system with a wiper.

Pierluigi Paganini

(SecurityAffairs – hacking, Norway)

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