A US court has allowed Microsoft to seize control of key domains of cybercriminals who used COVID-19-related lures in the phishing emails to target its customers in 62 countries and access Office 365 account contents, including email, contacts, notes and material.
The US District Court for the Eastern District of Virginia on Tuesday unsealed documents detailing Microsoft's work to disrupt cybercriminals that were taking advantage of the COVID-19 pandemic in an attempt to defraud its users.
Microsoft's Digital Crimes Unit (DCU) first observed these criminals in December 2019, when they deployed a sophisticated, new phishing scheme designed to compromise customer accounts.
Microsoft later observed renewed attempts by the same criminals, this time using COVID-19-related lures in the phishing emails to target victims.
"This malicious activity is yet another form of business email compromise (BEC) attack, which has increased in complexity, sophistication and frequency in recent years," Tom Burt, Corporate Vice President, Customer Security & Trust, said in a statement.
According to the FBI's 2019 Internet Crime Report, the most-costly complaints received by their Internet Crime Complaint Center (IC3) involved BEC crimes, with losses of over $1.7 billion, representing nearly half of all financial losses due to cybercrime.
The phishing emails instead contained messages regarding COVID-19 as a means to exploit pandemic-related financial concerns and induce targeted victims to click on malicious links.
Once victims clicked on the deceptive links, they were ultimately prompted to grant access permissions to a malicious web application (web app).
Web apps are familiar-looking as they are widely used in organizations to drive productivity, create efficiencies and increase security in a distributed network.
Unknown to the victim, these malicious web apps were controlled by the criminals, who, with fraudulently obtained permission, could access the victim's Microsoft Office 365 account, said Microsoft.
This scheme enabled unauthorized access without explicitly requiring the victims to directly give up their login credentials at a fake website or similar interface, as they would in a more traditional phishing campaign.
After clicking through the consent prompt for the malicious web app, the victim unwittingly granted criminals permission to access and control the victims' Office 365 account contents, including email, contacts, notes and material stored in the victims' OneDrive for Business cloud storage space and corporate SharePoint document management and storage system.
The company said that this unique civil case against COVID-19-themed BEC attacks "has allowed us to proactively disable key domains that are part of the criminals' malicious infrastructure, which is a critical step in protecting our customers".
While the lures may have changed, the underlying threats remain, evolve and grow, and it's more important than ever to remain vigilant against cyber attacks, the company added.