Kaseya noted Sunday it had received no new reports of compromise since Saturday.
The company is working with both theFBIand the USCybersecurity and Infrastructure Agencyto investigate the attack.
Security firmsHuntress LabsandSophos Labshave likewise pointed to REvil.
Some of the victims received demands for $5 million in ransom, the Times reported.
Biden has directed intelligence agencies to look into the matter, Reuters reported.
Biden said he would be briefed on the Kaseya attack Sunday.
The statement didn’t offer an assessment on the source of the attack.
The Russian Embassy in Washington didn’t respond to a request for comment.
The FBI asked that victims report the attack to itsInternet Crime Complaint Center.
CNET’s Natalie Weinstein contributed to this report.