zlacker

>>jakels+(OP)
> I also enabled UFW (which I should have done ages ago)

I disrecommend UFW.

firewalld is a much better pick in current year and will not grow unmaintainable the way UFW rules can.

    firewall-cmd --persistent --set-default-zone=block
    firewall-cmd --persistent --zone=block --add-service=ssh
    firewall-cmd --persistent --zone=block --add-service=https
    firewall-cmd --persistent --zone=block --add-port=80/tcp
    firewall-cmd --reload

Configuration is backed by xml files in /etc/firewalld and /usr/lib/firewalld instead of the brittle pile of sticks that is the ufw rules files. Use the nftables backend unless you have your own reasons for needing legacy iptables.

Specifically for docker it is a very common gotcha that the container runtime can and will bypass firewall rules and open ports anyway. Depending on your configuration, those firewall rules in OP may not actually do anything to prevent docker from opening incoming ports.

Newer versions of firewalld gives an easy way to configure this via StrictForwardPorts=yes in /etc/firewalld/firewalld.conf.

>>3np+pm
it doesn't matter what netfilter frontend you use if you allow outbound connections from any binary.

In order to stop these attacks, restrict outbound connections from unknown / not allowed binaries.

This kind of malware in particular requires outbound connections to the mining pools. Others downloads scripts or binaries from remote servers, or try to communicate with their c2c servers.

On the other hand, removing exec permissions to /tmp, /var/tmp and /dev/shm is also useful.

>>gus_+qy
Is there an automated way of doing this?

>>3abito+gP
restricting outbound connections by binary: OpenSnitch .

You can also restrict outbound connections to cryptomining pools and malicious IPs. For example by using IOCs from VirusTotal or urlhaus.bazaar.ch