Kaspersky should just ignore it.

They should 1) Continue to provide updates, 2) do their utmost to prevent blocking of updates, provide updates through tor or some other service that makes it very, very hard to block for the US. 3) Do what US VPN providers did when they couldn't do business in Russia anymore which is give all existing customers free usage of the product until such time the market is available again.

Further they should start openly attributing to the US spyware they uncover instead of doing their usual diplomatic analysis of "looks similar to many western government associated actors".

What annoys the shit out of me about this conversation that's going to be had is if they had fears about them taking data and files well they could pass a law that applies to all AV companies and applies strict privacy policies to them but they'd never do that because all western backed AV and info-sec companies are infested up to the gills if not literally founded by funded by national security state ghouls (former of course they'd claim but no such creature).

Sadly Kaspersky are kind of like many Russians, too diplomatic, eager to bend the knee. They should absolutely do what western companies into the anti-Russian propaganda did but in reverse, claim it's their duty to continue protecting their customers especially in repressive western states.

They will absolutely sue of course. They regularly sue copyright trolls and all kinds of others but as I understand it this kind of listing is basically entirely at the pleasure of the US government and they can just sit in court and keep repeating nothing but the words "national security, sources classified, trust us" and win the case because commerce dept I believe has authority to sanction whoever they please.