Businesses rushed Saturday to contain a ransomware attack that has paralyzed their computer networks, a situation complicated in the U.S. by offices lightly staffed at the start of the Fourth of July holiday weekend.
In Sweden, most of the grocery chain Coop’s 800 stores were unable to open because their cash registers weren’t working, according to SVT, the country’s public broadcaster. The Swedish State Railways and a prominent local pharmacy chain were also affected.
Cybersecurity experts say the REvil gang, a major Russian-speaking ransomware syndicate, appears to be behind the attack that targeted a software supplier called Kaseya, using its network-management package as a conduit to spread the ransomware through cloud-service providers.
Kaseya CEO Fred Voccola said in a statement that the company believes it has identified the source of the vulnerability and will “release that patch as quickly as possible to get our customers back up and running.”
John Hammond of the security firm Huntress Labs said he was aware of some managed-services providers — companies that host IT infrastructure for multiple customers — being hit by the ransomware, which encrypts networks until the victims pay off attackers.
“It’s reasonable to think this could potentially be impacting thousands of small businesses,” said Hammond, basing his estimate on the service providers reaching out to his company for assistance and comments on Reddit showing how others are responding.
Voccola said fewer than 40 of Kaseya’s customers were known to be affected. However, the ransomware could still affect hundreds of more companies that rely on Kaseya’s clients that provide broader IT services.
Voccola said the problem is only affects-premise” customers, which means organizations runningrunown data centers. It’s not affecting its cloud-based services running software for customers, though Kaseya also shut down those servers as a precaution, he said.
The company added in a statement Saturday that “customers who experienced ransomware and receive a communication from the attackers should not click on any links — they may be weaponized.”
Gartner analyst Katell Thielemann said it’s clear that Kaseya quickly sprang to action, but it’s less clear whether their affected clients had the same level of preparedness.
“They reacted with an abundance of caution,” she said. “But the reality of this event is it was architected for maximum impact, combining a supply chain attack with a ransomware attack.” Supply chain attacks are those that typically infiltrate widely used software and spread malware as it updates automatically.
Complicating the response is that it happened at the start of a major holiday weekend in the U.S. when most corporate IT teams aren’t fully staffed. That could also leave those organizations unable to address other security vulnerabilities, such as a dangerous Microsoft bug affecting software for print jobs, said James Shank of threat intelligence firm Team Cymru. “Customers of Kaseya are in the worst possible situation,” he said. “They’re racing against time to get the updates out on other critical bugs.”