Submission + - Systemd wants to expand to include a sudo replacement (fosspost.org)
An anonymous reader writes: Systemd lead developer Lennart Poettering has posted on Mastodon about their upcoming v256 release of Systemd, which is expected to include a sudo replacement called “run0”.
The developer talks about the weaknesses of sudo, and how it has a large possible attack surface. For example, sudo supports network access, LDAP configurations, other types of plugins, and much more. But most importantly, its SUID binary provides a large attack service according to Lennart:
"I personally think that the biggest problem with sudo is the fact it’s a SUID binary though – the big attack surface, the plugins, network access and so on that come after it it just make the key problem worse, but are not in themselves the main issue with sudo. SUID processes are weird concepts: they are invoked by unprivileged code and inherit the execution context intended for and controlled by unprivileged code. By execution context I mean the myriad of properties that a process has on Linux these days, from environment variables, process scheduling properties, cgroup assignments, security contexts, file descriptors passed, and so on and so on."
He’s saying that sudo is a Unix concept from many decades ago, and a better privilege escalation system should be in place for 2024 security standards:
"So, in my ideal world, we’d have an OS entirely without SUID. Let’s throw out the concept of SUID on the dump of UNIX’ bad ideas. An execution context for privileged code that is half under the control of unprivileged code and that needs careful manual clean-up is just not how security engineering should be done in 2024 anymore."
The developer talks about the weaknesses of sudo, and how it has a large possible attack surface. For example, sudo supports network access, LDAP configurations, other types of plugins, and much more. But most importantly, its SUID binary provides a large attack service according to Lennart:
"I personally think that the biggest problem with sudo is the fact it’s a SUID binary though – the big attack surface, the plugins, network access and so on that come after it it just make the key problem worse, but are not in themselves the main issue with sudo. SUID processes are weird concepts: they are invoked by unprivileged code and inherit the execution context intended for and controlled by unprivileged code. By execution context I mean the myriad of properties that a process has on Linux these days, from environment variables, process scheduling properties, cgroup assignments, security contexts, file descriptors passed, and so on and so on."
He’s saying that sudo is a Unix concept from many decades ago, and a better privilege escalation system should be in place for 2024 security standards:
"So, in my ideal world, we’d have an OS entirely without SUID. Let’s throw out the concept of SUID on the dump of UNIX’ bad ideas. An execution context for privileged code that is half under the control of unprivileged code and that needs careful manual clean-up is just not how security engineering should be done in 2024 anymore."
