Trivial in the sense that in 99.9% of situations, "npm install" is immediately followed by "npm run", "npm test", or some form of execution. Any execution that imports a dependency is enough for a transitive dependency to execute its malicious payload immediately.

Post-install scripts have a slight edge over executing malicious code on import, i.e. they work 99.95% of the time instead of 99.9% of the time, but removing these scripts wouldn't materially change the situation we're in. You're locking the back door but leaving the front door and all of the windows wide open.

I'm going to suggest that we might be worse off in the short-medium term if post-install scripts are removed because everyone who thought that disabling post-install scripts was a "good enough" standalone security strategy will get caught with their pants down as attackers modify their payloads.

▲ throwaway27448 a month ago | parent | next [-]

> Post-install scripts have a slight edge over executing malicious code on import, i.e. they work 99.95% of the time instead of 99.9% of the time

The "instead of" depends very much on the exploit and where it's wedged in the code. I doubt it's anywhere near 99%. Plus, getting the exploit to execute on the developer's machine is difficult to manage even in the best cases.

> because everyone who thought that disabling post-install scripts was a "good enough" standalone security strategy will get caught with their pants down as attackers modify their payloads.

Saying "well there are stupid people in the world" seems like a pretty bad justification to leave a hole open.

	▲	dns_snek a month ago \| parent [-]
		> The "instead of" depends very much on the exploit and where it's wedged in the code. I doubt it's anywhere near 99%. Plus, getting the exploit to execute on the developer's machine is difficult to manage even in the best cases. We don't need to guess, it's going to be wedged in index.js, probably on line 1. Are you aware that all transitive dependencies are executed immediately? You depend on PackageA which imports PackageB, which imports PackageC, which imports a trojanized PackageD. As soon as PackageD is imported, it executes its payload and infects your machine. All of this happens in a blink of an eye, as soon as you run anything that kicks off an import chain containing a trojanized dependency. Try it for yourself. This will simulate a malicious transitive dependency: koa > cookies > keygrip > tsscmp. You don't need to do anything except import koa. `mkdir demo && cd demo npm install --save koa@3.2.0 echo 'import "koa";' > demo.mjs echo 'console.log("\n\n--- pwned by a transitive dependency ---")' >> node_modules/tsscmp/lib/index.js node demo.mjs` > Saying "well there are stupid people in the world" seems like a pretty bad justification to leave a hole open Then you're calling much of the HN audience stupid. I've had this argument on here several times - and this is the top percentile of people who try to do something at all. The justification for leaving this hole open is that it's a waste of time, resources, and mindshare patching a hole when there's a comparable and unpatchable hole right next to it. Advocate for things that actually work, like sandboxes.

▲ cindyllm a month ago | parent | prev [-]

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