That lack of user interaction — or request for consent — is what confused and concerned some former Kaspersky customers.

US-based Kaspersky security solution users have been facing a unique situation in the past few days as their own antivirus software had been replaced with another one called UltraAV.

Some US-based users of Kaspersky antivirus products have found their software replaced by product from by a low-profile entity named "UltraAV" – a change they didn't ask for, and which has delivered them untested and largely unknown software from a source with a limited track record.

After U.S. ban, Kaspersky's American customers were automatically migrated to UltraAV antivirus, in some cases without the customers' knowledge.

Kaspersky deleted its anti-malware software from computers across the United States and replaced it with UltraAV's antivirus solution without warning.

"Following the recent decision by the U.S. Department of Commerce that prohibits Kaspersky from selling or updating certain antivirus products in the United States, Kaspersky part

Kaspersky antivirus software automatically deletes itself from U.S. users' computers and installs UltraAV without warning.

Last week, users of Kaspersky anti-virus software found that the software had been uninstalled from their computers and that UltraAV's anti-virus had been installed in its place. The users had not consented to or initiated any of it.