rpcbind tries to contact scan-06d.shadowserver.org - is my laptop compromised?
So the answer is - no, my laptop wasn't compromised. Little Snitch blocked a scan attempt from Open Portmapper Scanning Project - it appeared that that rpcbind (a.k.a portmapper service) on my laptop is openly accessible from the Internet. I solved this issue by blocking all incoming connections for /usr/sbin/rpcbind (System Preferences > Security &amp; Privacy > Firewall > Firewall Options, press +, find /usr/sbin/rpcbind, select "Block incoming connections").

Thanks @Tetsujin for pointing me into the right direction.