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by pkillarjun 636 days ago
First I thought, "S%%t, I am hacked," because I know in Fedora CUPSD is installed by default and runs at boot.

> /etc/cups/cupsd.conf

> Listen localhost:631

After some checking, I found out by default CUPSD only runs at localhost. So, yeah, you don't have to worry about this in Fedora either.

1 comments

That's the TCP port cupsd listens on. You want to look at the UDP port cups-browsed listens on (which is where the problem is, and it isn't configurable: if cups-browsed is running, you're probably vulnerable).

In general I would say don't look at config files to verify this kind of thing. Use something like 'ss -lp' to get a list of what processes on your machine are actually listening on (anything that isn't 127.0.0.* or [::1] is generally going to mean network-accessible)

> sudo lsof -n -i -P | grep -i "cups"

>cupsd 2843 root 7u IPv6 12941 0t0 TCP [::1]:631 (LISTEN)

>cupsd 2843 root 8u IPv4 12942 0t0 TCP 127.0.0.1:631 (LISTEN)

There is no open UDP port for CUPSD, so relax.

because it's a separate daemon that listens on UDP. But it looks like at least it's not enabled in your config.