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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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Firewalls: what SHOULD I block? (lemmy.wtf)

submitted 1 month ago by [email protected] to c/[email protected]

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Hey there folks,

I'm trying to figure out how to configure my UFW, and I'm just not sure where to start. What can I do to see the intetnet traffic from individual apps so I can know what I might want to block? This is just my personal computer and I'm a total newbie to configuring firewalls so I'm just not sure how to go about it. Most online guides seem to assume one already knows what they want to block but I don't even know how/where to monitor local traffic to figure out what I can/should consider blocking.

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[–] [email protected] 2 points 1 month ago (2 children)

run sudo ss -tulpn, and have a look at the processes and their privileges listening for incoming connections. If one of them has a vulnerability, through which a third party can make that software do things it was not intended for.. that's pretty bad.
This can most easily happen with software whose developers are underresouced/careless/stubborn.

A recent case of that happening: https://www.evilsocket.net/2024/09/26/Attacking-UNIX-systems-via-CUPS-Part-I/
Tl;Dr, remote code execution vulnerability in software that most often runs as root, automatically.

[–] [email protected] 1 points 1 month ago

I understand your point but I reiterate that I don't connect to unsafe networks. If someone has remote code execution on a device on my side of the network then they are also inside my apartment and I'd be more worried about that.

[–] [email protected] 1 points 1 month ago (1 children)

You don't understand local host. Services listen on 127.0.0.1 which is a local only address. You can only connect to it locally

[–] [email protected] 1 points 1 month ago

who speaks about localhost? out of 21 active ports on my machine, only 3 is only listening on localhost. dhclient, avahi-daemon, syncthing, kdeconnect.. cups-browsed did not listen only on localhost either