this post was submitted on 13 Mar 2025
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curl https://some-url/ | sh

I see this all over the place nowadays, even in communities that, I would think, should be security conscious. How is that safe? What's stopping the downloaded script from wiping my home directory? If you use this, how can you feel comfortable?

I understand that we have the same problems with the installed application, even if it was downloaded and installed manually. But I feel the bar for making a mistake in a shell script is much lower than in whatever language the main application is written. Don't we have something better than "sh" for this? Something with less power to do harm?

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[–] Zron@lemmy.world 15 points 2 days ago (1 children)

For security reasons, I review every line of code before it’s executed on my machine.

Before I die, I hope to take my ‘93 dell optiplex out of its box and finally see what this whole internet thing is about.

[–] moseschrute@lemmy.ml 7 points 2 days ago* (last edited 2 days ago)

Not good enough. You should really be inspecting your CPU with a microscope.

[–] Artyom@lemm.ee 41 points 2 days ago (1 children)

What's stopping the downloaded script from wiping my home directory?

What's stopping any Makefile, build script, or executable from running rm -rf ~? The correct answer is "nothing". PPAs are similarly open, things are a little safer if you only use your distro's default package sources, but it's always possible that a program will want to be able to delete something in your home directory, so it always has permission.

Containerized apps are the only way around this, where they get their own home directory.

[–] easily3667@lemmus.org 6 points 2 days ago* (last edited 2 days ago) (1 children)

Don't forget your package manager, running someone's installer as root

It's roughly the same state as when windows vista rolled out UAC in 2007 and everything still required admin rights because that's just how everything worked....but unlike Microsoft, Linux distros never did the thing of splitting off installs into admin vs unprivileged user installers.

[–] brian@programming.dev 5 points 2 days ago (1 children)

plenty of package managers have.

flatpak doesn't require any admin to install a new app

nixos doesn't run any code at all on your machine for just adding a package assuming it's already been cached. if it hasn't been cached it's run in a sandbox. the cases other package managers use post install configuration scripts for are a different mechanism which possibly has root access depending on what it is.

[–] easily3667@lemmus.org 1 points 1 day ago (1 children)

Gonna ignore nix since they have two users, but flatpak is fair. However flatpak is a sandboxing scheme which is distinct from per-user installs. In many cases it can be the better route but not always. I think the reason it's popular on Linux is also the dll hell problem.

[–] brian@programming.dev 1 points 1 day ago

idk if 2 users is fair, it may just be my circles but I see nixos mentioned more than almost anything else on lemmy/hn/etc in the past couple years

[–] WolfLink@sh.itjust.works 14 points 2 days ago* (last edited 2 days ago)

It isn’t more dangerous than running a binary downloaded from them by any other means. It isn’t more dangerous than downloaded installer programs common with Windows.

TBH macOS has had the more secure idea of by default using sandboxes applications downloaded directly without any sort of installer. Linux is starting to head in that direction now with things like Flatpak.

What's stopping the downloaded script from wiping my home directory?

Lol. Lmao

[–] emberpunk@lemmy.ml 6 points 2 days ago

You could just read the script file first.. Or YOLO trust it like you trust any file downloaded from a relatively safe source.. At least you can read a script.

[–] ExperimentalGuy@programming.dev 13 points 2 days ago

If you're worried, download it into a file first and read it.

[–] Kissaki@programming.dev 2 points 1 day ago

| sh stands for shake head at bad practices

[–] Gronk@aussie.zone 1 points 1 day ago

Yeah I hate this stuff too, I usually pipe it into a file figure out what it's doing and manually install the program from there.

FWIW I've never found anything malicious from these scripts but my internal dialogue starts screaming when I see these in the wild, I don't want to run some script and not know what it's touching malicious or not it's a PITA.

As a linux user, I like to know what's happening under the hood as best I can and these scripts go against that

[–] zygo_histo_morpheus@programming.dev 87 points 3 days ago (13 children)

You have the option of piping it into a file instead, inspecting that file for yourself and then running it, or running it in some sandboxed environment. Ultimately though, if you are downloading software over the internet you have to place a certain amount of trust in the person your downloading the software from. Even if you're absolutely sure that the download script doesn't wipe your home directory, you're going to have to run the program at some point and it could just as easily wipe your home directory at that point instead.

[–] HelloRoot@lemy.lol 33 points 3 days ago (6 children)

All the software I have is downloaded from the internet...

[–] WhatAmLemmy@lemmy.world 27 points 3 days ago* (last edited 3 days ago)

You should try downloading the software from your mind brain, like us elite hackers do it. Just dump the binary from memory into a txt file and exe that shit, playa!

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[–] easily3667@lemmus.org 10 points 2 days ago (1 children)

This is just normal Linux poor security. Even giants like docker do this.

Docker doesn't do this anymore. Their install script got moved to "only do this for testing".

Use a convenience script. Only recommended for testing and development environments.

Now, their install page recommends packages/repos first, and then a manual install of the binaries second.

[–] thomask@lemmy.sdf.org 15 points 3 days ago* (last edited 3 days ago) (1 children)

The security concerns are often overblown. The bigger problem for me is I don't know what kind of mess it's going to make or whether I can undo it. If it's a .deb or even a tarball to extract in /usr/local then I know how to uninstall.

I will still use them sometimes but for things I know and understand - e.g. rustup will put things in ~/.rustup and update the PATH in my shell profile and because I know that's what it does I'm happy to use the automation on a new system.

[–] jagged_circle@feddit.nl 6 points 2 days ago (17 children)

Damn that's bad misinformation. Its a security nightmare

[–] thomask@lemmy.sdf.org 10 points 2 days ago* (last edited 2 days ago) (7 children)

So tell me: if I download and run a bash script over https, or a .deb file over https and then install it, why is the former a "security nightmare" and the latter not?

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[–] billwashere@lemmy.world 19 points 3 days ago (3 children)
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[–] lemmeBe@sh.itjust.works 24 points 3 days ago (15 children)

I think safer approach is to:

  1. Download the script first, review its contents, and then execute.
  2. Ensure the URL uses HTTPS to reduce the risk of man-in-the-middle attacks

If steam accidentally deleted someone's home directory in a bash script via a single error, I doubt I would catch that one myself.

[–] stevedice@sh.itjust.works 14 points 3 days ago (4 children)

If you've downloaded and audited the script, there's no reason to pipe it from curl to sh, just run it. No https necessary.

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[–] tatterdemalion@programming.dev 7 points 2 days ago (1 children)

Back up your data folks. You're probably more likely to accidentally rm -rf yourself than download a script that will do it.

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[–] Boomkop3@reddthat.com 4 points 2 days ago

And don't forget to sudo!

[–] syklemil@discuss.tchncs.de 28 points 3 days ago

This is simpler than the download, ./configure, make, make install steps we had some decades ago, but not all that different in that you wind up with arbitrary, unmanaged stuff.

Preferably use the distro native packages, or else their build system if it's easily available (e.g. AUR in Arch)

[–] Undaunted@feddit.org 21 points 3 days ago (6 children)

You shouldn't install software from someone you don't trust anyway because even if the installation process is save, the software itself can do whatever it has permission to.

"So if you trust their software, why not their install script?" you might ask. Well, it is detectable on server side, if you download the script or pipe it into a shell. So even if the vendor it trustworthy, there could be a malicious middle man, that gives you the original and harmless script, when you download it, and serves you a malicious one when you pipe it into your shell.

And I think this is not obvious and very scary.

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