On Tuesday, August 27, 2019 5:36:20 AM MST Björn Persson wrote: > Please elaborate. Where does the script come from, what exactly happens > by accident, and how would a packet filter stop it?
It could come from anywhere, that's not the point. A *firewall* would stop it from doing anything too harmful: Opening up the system to the world by binding a port, or listening on a UDP port. It'd still be bound, or would still be listening on a port, but it wouldn't be accessible unless somebody went and manually opened a port on the firewall. > A badly written script accidentally starts some network service that it > doesn't need? The one time that actually happens, the user will likely > click "allow" without thinking, as they will have been accustomed to > doing so all the time. > > > If the script actually needs to listen on the network, then the user > will have to allow it, and the script is no less badly written than it > was before. There is no "allow" button. I don't know what you're talking about. Additionally, I'm referring to incidents like that common in node.js, where a package gets modified to something malicious, and then runs a backdoor which is accessible over a given port. > How would a "vulnerability" "bind a port"? If the program is supposed > to communicate, then it will be allowed, and any vulnerabilities it has > are then exposed to the network. If it's not supposed to communicate, > then it won't randomly sprout a network service because of a bug. For example, RCEs, specific or otherwise. This has happened in `firefox` before. > If you mean that an arbitrary code execution vulnerability has been > exploited, so that the program is now executing the attacker's code, > then it's already too late. The attack code won't listen for incoming > connections. It will make an outgoing connection to its master. And in > case you're considering requiring permission even for outgoing > connections – which would be unbearable to the user – the attack code > would just make an API call (through Dbus or whatever) to grant itself > permission to communicate. Just because a potential attacker may have already compromised part of a system doesn't mean that you just open up the firewall to anything they've got listening. Additionally, such a thing trying to open a port would likely require Polkit to grant you permission to do so first, which would, by default, require the user to authenticate and have the appropriate permissions. -- John M. Harris, Jr. <joh...@splentity.com> Splentity https://splentity.com/ _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org
