Wouldn't this bash script be just as susceptible to supply chain attacks? What dependencies does openssl, cURL, sed, grep, awk, mktemp pull in, and could it be vulnerable to attack like we saw with xz?
I think the point is to minimize the total attack surface on a system. If the bash script only depends on programs like those you list, which Linux distros package as default anyway, the shell script has not introduced any new dependencies on your system.
> Wouldn't this bash script be just as susceptible to supply chain attacks? What dependencies does openssl, cURL, sed, grep, awk, mktemp pull in, and could it be vulnerable to attack like we saw with xz?
All the packages listed are already probably installed on your system, so you have to worry about their integrity already (your system package manager (RPM, Deb) probably leverages them).
Something like Certbot pulls in dependencies on top of what your system already has, whereas Dehydrated or Acme.sh use tools that you already have to worry about anyway because they're part of the base OS.
I’m pretty sure every open source repository ever created is vulnerable to “an attack like we saw with xz,” and by that I mean a labyrinthine, multi-year effort involving highly sophisticated exploits combined with psychological manipulation, coordinated sock-puppets, global actors, and deep intrigue—to the extent that it’s absurd to cite as a threat that “dependency management” can meaningfully prevent.
I actually full source bootstrapped a Linux distribution from zero recently. Most distros have a lot of dependencies you do not need.
In this case you only actually need curl, openssl, and busybox. Those depend on at least a small libc implementation and a kernel but those are certainly already present.
Coreutils or busybox is probably already installed too. Still, I will grant the requirement of musl and a linux kernel since we are being pedantic or maybe talking about an embedded linux use case, so 5 deps total to boot from metal and get a cert.
To be fair I would never actually ship openssl or busybox in a real embedded project. Would probably write a simple standalone binary using the standard library of Go or something.
How is that in any way realistic? Most people don't bootstrap Linux systems. And just because it is pre-installed doesn't make it safe. Most software on a modern Linux distribution is dynamically linked to several libraries which might depend on other libraries.
