what's the mitigation?
Based on their (lack of) response, the mitigation is to uninstall Steam. Obviously that's a crap answer if you have a lot of money tied up in games on their platform.
If that's not an option, you could dedicate a PC to Steam (and only Steam), VLAN it away from everything else on your network, and back it up frequently to offline storage.
Biting the hand that feeds IT
