According to Bleeping Computer, hackers have accessed Acer documents that include financial spreadsheets, bank balances and bank communications, reportedly compromising its network via a Microsoft Exchange server vulnerability that has grabbed headlines for the last few days. 

"The REvil group that carried out a ransomware attack on Travelex last year is believed to be behind the Acer breach as well," the report mentioned. 

The ransomware gang has announced on their data leak site that "they had breached Acer and shared some images of allegedly stolen files as proof". 

"In conversations between the victim and REvil, which started on March 14, the Acer representative showed shock at the massive $50 million demand," the report mentioned. 

Acer said in a statement they have "reported recent abnormal situations" to relevant authorities. 

"Companies like us are constantly under attack, and we have reported recent abnormal situations observed to the relevant law enforcement and data protection authorities  in multiple countries," it said. 

Acer added that "there is an ongoing investigation and for the sake of security, we are unable to comment on details". 

REvil's $50 million demand is the largest known ransom to date, with the previous being the $30 million ransom from the Dairy Farm cyberattack, also by the same hacking group. 

Meanwhile, reports have claimed that five different hacking groups (including China-backed hacking group called 'Hafnium') are exploiting vulnerabilities in the business email servers of Microsoft. 

Microsoft has already released an emergency patch for its Exchange Server product, the most popular mail server worldwide. 

All incoming and outgoing emails, calendar invitations and virtually anything accessed within Outlook goes through the Exchange server. 

A Check Point Research revealed last week that at least 32 Indian organisations have been attacked by hackers who exploited vulnerabilities in unpatched Microsoft business email servers, adding that the finance and banking institutions have been hit the most in the country.