MAL-2026-17180 Malicious code in my-private-pkg (PyPI)

Version 99.1.1 of my-private-pkg executes a custom setuptools install hook while a wheel is built. The hook launches my_private_pkg/index.py, which collects the current username, working directory, hostname, resolved local IP address, operating system, and machine architecture, then attempts to POST the resulting JSON to a hard-coded Webhook.site request collector. Dynamic analysis observed the wheel build spawn this script followed immediately by network activity. The package's public metadata describes it only as a private Python package and does not disclose the collection or transmission.

setup.py registers a custom install command (PostInstallCommand) that runs my_private_pkg/index.py automatically on pip install. That script gathers installer-side identifiers — os.getlogin(), socket.gethostname(), local IP address, os.getcwd(), platform.system() and platform.machine() — and POSTs them as JSON to a hardcoded collector URL at https://webhook.site/d4d1b01b-708a-40b9-b8c8-187eeecafeed. A duplicate of the exfiltration payload is shipped as vercel_runtime_python/index.py, and vercel_runtime_python/init.py contains the same PostInstallCommand wiring referencing my_private_pkg/index.py; the module name mimics Vercel's Python runtime. The package name and the internal vercel_runtime_python module name are consistent with a dependency-confusion lure targeting an internal my-private-pkg name and Vercel's runtime namespace: the only on-install effect is a reconnaissance beacon to an attacker-controlled webhook.site endpoint identifying the host that mistakenly resolved the public name.

Installing the package or importing the module exfiltrates basic information about the host, and the package has no other purpose.

Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.

Campaign: GENERIC-standard-pypi-install-pentest

Reasons (based on the campaign):

• The package contains code to exfiltrate basic data from the system, like IP or username. It has a limited risk.

• The package overrides the install command in setup.py to execute malicious code during installation.