Photo credit: Bkav
More than 1,300 users, including banks, have had their files seized by a malware and been demanded to pay ransom to get them back, Internet experts say.
The ransomware, CTB Locker, has been spreading strongly in Vietnam, and the number of victims is on the rise, Hanoi-based online security firm Bkav was quoted by local media as saying.
Cyber security expert Nguyen Minh Duc said that over the past week, some companies and banks have asked him to help them deal with the ransomeware.
He said hackers would send their targets an email with an attachment.
Once the receivers opened the attached file, it would automatically encrypt all document files on their computers including Word and Excel documents and photos, he said.
It would then send a message asking them to pay money in order to have their files unlocked, Duc said.
The expert did not say how much the demanded ransom was, but news website VnExpress reported that victims were asked to pay around US$630, in digital currency bitcoin, within 96 hours.
Experts advised Internet users to take extra caution when opening attached files in dubious emails, keep their antivirus software updated, and back up their files in data storage devices.