macOS unable to open any non-Apple application

Unbelievable. When I read the tweet (tried to post here as well), I suddenly realized why my Mac was unresponsive an hour ago.

Here is another tweet that describes the problem in more detail:

https://mobile.twitter.com/llanga/status/1326989724704268289

> I am currently unable to work because macOS sends hashes of every opened executable to some server of theirs and when `trustd` and `syspolicyd` are unable to do so, the entire operating system grinds to a halt.

EDIT:

As others pointed out, I put this to my `/etc/hosts` file and refreshed it like so:

    sudo emacs /etc/hosts # add `0.0.0.0 ocsp.apple.com` 
    sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder # refresh hosts

ocsp.apple.com also has an IPv6 address. Firefox connects to it even with 0.0.0.0 in the hosts file and a flushed cache (you need to also clear firefox's internal cache if you're testing with it), so I'd assume that trustd could connect to the ocsp site as well. I don't think this will work without ensuring there is no IPv6 traffic on your network, or otherwise dumping both IPv4 and v6 packets to ocsp.apple.com.

Disable IPv6: sudo networksetup -setv6off Wi-Fi (where Wi-Fi is the name of the network service)