TORONTO — A shadowy group of cyber criminals that attacked a prominent nursing organization and Canadian Tire store has successfully targeted other companies with clients in governments, health care, insurance and other sectors.
Posts on their NetWalker “blog” indicate the recent infiltration of cloud-services company Accreon and document company Xpertdoc, although only the College of Nurses of Ontario has publicly acknowledged being victimized.
Experts say NetWalker surfaced about a year ago but its attacks took off in March as the criminals exploited fears of COVID and people working remotely. The ransomware, like similar malware, often infiltrates computer networks via phishing emails. Such messages masquerade as genuine, prompting users to provide log-in information or inadvertently download malware.
Earlier ransomware attacks focused on encrypting a target’s files — putting them and even backups out of reach. Increasingly, attackers also threaten to publish data stolen during their “dwell time,” the days or weeks spent inside an exploited network before encryption and detection.
The intruders promise to provide a decryption key and to destroy stolen records if the organization pays a ransom, often based on what the attackers have learned about its finances, by a given deadline.
To underscore the extortion, NetWalker criminals publish tantalizing screen shots of information they have, such as personnel, financial, legal and health records.
“The data in these cases is extremely sensitive,” said Brett Callow, a Vancouver Island-based threat analyst with cyber-security firm, Emsisoft. “Lots of companies choose not to disclose these incidents, so the individuals and (third-party) organizations whose data have been compromised never find out.”
In an interview, Richard Brossoit, CEO of Montreal-based Xpertdoc, said this month’s attack was a “little terrifying” at first. Fortunately, he said, damage was limited and no confidential client or personal information was compromised,