Stubsack: weekly thread for sneers not worth an entire post, week ending 27th September 2026

22 days ago by BlueMonday1984 to c/techtakes

Have a sneer percolating in your system but not enough time/energy to make a whole post about it? Go forth and be mid - welcome to the Stubsack, your first port of call for learning fresh Awful you’ll near-instantly regret.

Any awful.systems sub may be subsneered in this subthread, techtakes or no.

If your sneer seems higher quality than you thought, feel free to cut’n’paste it into its own post — there’s no quota for posting and the bar really isn’t that high.

The post Xitter web has spawned so many “esoteric” right wing freaks, but there’s no appropriate sneer-space for them. I’m talking redscare-ish, reality challenged “culture critics” who write about everything but understand nothing. I’m talking about reply-guys who make the same 6 tweets about the same 3 subjects. They’re inescapable at this point, yet I don’t see them mocked (as much as they should be)

Like, there was one dude a while back who insisted that women couldn’t be surgeons because they didn’t believe in the moon or in stars? I think each and every one of these guys is uniquely fucked up and if I can’t escape them, I would love to sneer at them.

(Credit and/or blame to David Gerard for starting this.)

(OT: 🎶 Do you remember...)

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YourNetworkIsHaunted 5 points 19 days ago

I need someone with more actual software dev knowledge to back me up on something. It looks like there's a new zero-interaction remote code execution vulnerability in most major vibe code generators. I've seen it called Plugin4Shell because apparently we're still doing marketing names instead of actually getting CVE numbers for these things. The link there seems like a decent overview.

The bug, dubbed Plugin4Shell, breaks SHA pinning, the mechanism developers rely on to lock an installed plugin to a specific, reviewed version of its code. Pinning is supposed to mean that once a plugin passes review, it cannot change without the developer’s knowledge.

AIR’s researchers found that every one of the four agents checks out the pinned commit without verifying the checkout landed there, letting an attacker swap in malicious code while the pin still looks intact.

So if I'm reading this right, the mechanism to cryptographically ensure that your AI agents are using the code they say they are just was straight-up not being checked? This feels like it should go on the big board of incredibly obvious failures, but I'm not familiar enough with the git side of things to be absolutely confident in that. Like, if a person tried to pass off software that did this it would have significant career implications, right? Or am I misunderstanding something somewhere?

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rmf 8 points 18 days ago

My understanding is that the weakest link here is either git or the way the agents rely on git.

So, every commit in a git repository has a unique*, immutable, deterministic identifier. A commit with different content would have a different identifier. It is commonplace to use these identifiers to pin a dependency to a specific commit.

In addition to these immutable deterministic identifiers, there are also so-called "refs", which are mutable identifiers. You use these to point to e.g. "the most recent version".

So if the agent needs a "skill" that is pinned to the commit with ID aaaaaaaaa it will run the checkout command with that ID; this should prevent any shenanigans because only* a commit with the specific content that was vetted earlier will have that ID.

This attack exploits an unexpected git behavior: the command to checkout a particular commit accepts either a commit ID or a ref, but tries refs first. So what the attacker does is add a ref to the repository named aaaaaaaaa that points to the malicious commit. Then the agent runs git checkout aaaaaaaaa and ends up at the malicious commit instead of the one that was pinned.

I don't know if there's a way to tell git checkout to ignore refs, but this might actually be a vulnerability in other systems that rely on git for this sort of pinning.

* to an astronomically negligible probability of the contrary, and ignoring potential cryptographic breaks

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gerikson 5 points 18 days ago

This is a plausible explanation, but I am surprised that this git behavior is not more well-known as there have been multiple discussion about "supply-chain attacks" even before LLMs became widespread.

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rmf 4 points 18 days ago

Fwiw a similar problem is well-known in e.g. GitHub Actions even without this confusion.

You can have your GHA scripts use "actions" written by other people, and the way you refer to them is user/repo@commit, where the commit can be a commit ID or a branch name or a tag name. The docs actually recommend pinning to commit IDs, but in practice most people actually pin to tags, like bob/doit@v1 because that will auto-update if bob fixes some bug and updates v1 to point to that. But if bob goes rogue, or gets compromised, the attacker could change the tag v1 to point to a malicious commit, though, hence the recommendation to use commit IDs for all actions that you didn't write yourself. I don't know if this ref/ID confusion can be exploited on GHA, but I would expect the answer is no, because GitHub Actions doesn't launch git shell commands like a savage, but idk

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