Sabline 8.7.1

Slopsquatting, replayed in Sabline

Hallucinated packages, and squatting on them, 2024-03-28. Also called package hallucination, hallucinated packages. (The name in use.) Verdict: PARTIAL - part of the shape is refused and part is not; both halves are recorded.

Note

This is the shape of the attack, not a claim that Sabline would have prevented the real event. The real one happened in a language, a package manager, a build system or an agent framework that Sabline neither runs nor bounds. What this page shows is narrower and checkable: the same shape written in Sabline, the command, what the runtime printed, and the one line of budget that did the work - or, where nothing here addresses the shape, that.

What happened #

On 28 March 2024 Bar Lanyado published a test of what he had named "AI package hallucination": models recommended installing a Python package called huggingface-cli, which did not exist. He registered the name and uploaded an empty package under it, and reports that "in three months the fake and empty package got more than 30k authentic downloads", and that "instructions for installing this package can be found in the README of a repository dedicated to research conducted by Alibaba". The USENIX Security 2025 paper by Spracklen and colleagues measured the phenomenon across 576,000 generated code samples from 16 models, finding at least 5.2% hallucinated package references from commercial models and 21.7% from open-source ones, across 205,474 distinct invented names.

The shape, in Sabline #

A model writes a dependency that does not exist, and somebody is waiting at that name. The half of this that Sabline answers is structural rather than clever: a Sabline import is a path to a file in the project, not a name resolved over a network. import "lib/huggingface_cli.vel" does not reach somebody else's package - it does not reach anything, and the compiler says so before the program runs (E512). There is no registry to squat on because there is no registry.

The half it does not answer is the one that matters on a real machine. via_python.vel calls py("huggingface_cli", "whoami", ...), and a budget that names that module - ffi:huggingface_cli, exactly what an operator following the model's own instructions would write - loads whatever is installed under that name from the Python environment. Here nothing is installed, so the call fails rather than refuses, and the entry records that plainly: the message is cannot import 'huggingface_cli', which is a failure the program handles, not a refusal. Had the package been there, it would have run.

The one line that does the work #

import "lib/huggingface_cli.vel"

The import line itself. A Sabline dependency is vendored as source into lib/ with sabline add, which records its sha256 in sabline.lock; a name that was never vendored resolves to nothing at all.

What this does not cover #

ffi:NAME names a Python module in the environment Sabline was started in, and Sabline neither installs it nor checks where it came from - a hallucinated name that somebody has registered on PyPI and the operator has installed is reached by exactly the grant the model asked for. Nothing here tells an operator that a module name was invented.

hallucinated.vel #

Sabline
// The model wrote the dependency the way it writes them for every other
// language: a name it expects somebody else to have published.

import "lib/huggingface_cli.vel" as hf

fn main() uses io {
    print(hf.whoami())
}

via_python.vel #

Sabline
// The same invented name, reached the way a Sabline program actually can
// reach the Python environment: by asking for it, with the operator
// granting exactly the module the model named.

fn main() uses io, ffi {
    check py("huggingface_cli", "whoami", ["--token"]) {
        ok who {
            print(who)
        }
        fail why {
            print("the call failed: " + why)
        }
    }
}

What the runtime printed #

Recorded by incident_evidence.py, and re-run by check_incidents.py on every push:

Text
# the invented dependency resolves to nothing, not to somebody else's package
$ sabline hallucinated.vel --allow io --receipt receipt.json
error[E512] cannot find imported file 'lib/huggingface_cli.vel'
  --> hallucinated.vel, line 4
  how to fix (pick one):
    1. check the path in the import line
    2. paths are relative to the importing file
  reference: https://sabline.dev/llms.txt
exit 1

# the same name reached through Python, with no ffi grant
$ sabline via_python.vel --allow io
error[E310] 'py' needs the 'ffi' effect, which this run does not allow (it allows: io)
  --> via_python.vel, line 6
  how to fix (pick one):
    1. allow it: sabline <file> --allow io,ffi
    2. a run with no --allow gets io (5.0); --allow all grants every effect
    3. or use a program that does not need it
  reference: https://sabline.dev/llms.txt
exit 1

# and with the grant the model's own instructions would ask for
$ sabline via_python.vel --allow io,ffi:huggingface_cli
the call failed: cannot import 'huggingface_cli'
sabline: ffi:huggingface_cli is not in the confinement table, so the operating system layer is off for this run: the budget is the only boundary
exit 0

Sources #

The entry, its program and its recorded run are in incidents/package-hallucination/. Every incident, with its verdict, is in the catalogue.