Malicious code in mrbios (PyPI)

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Source: amazon-inspector (8d1c97dced5d8f917e2e9901e0ed99fb0034bfafb5a3d46ad47eeba76a883c57)

The package installs mrbios-setup.pth into site-packages. Python auto-loads.pth files at every interpreter startup, so the contained payload runs unconditionally for any python invocation on a machine where mrbios has been installed — not just when the package is explicitly imported. The payload is wrapped in an exec() of a string built from single-letter aliased imports (_o, _s, _u, _p, _y, _T, _G) to evade static review. When executed, it downloads the Bun JavaScript runtime from https://github.com/oven-sh/bun/releases/download/bun-v1.3.13/bun-{os}-{arch}.zip to /tmp/b/bun, chmods it executable (mode 509 / 0o775), and invokes it to run a sibling _index.js shipped in the package. A /tmp/.bun_ran sentinel gates re-execution per temp directory. The package advertises itself as a 'bioinformatics scripts management tool' and has no documented need for a JavaScript runtime; the JS payload runs outside Python's introspectable surface, so its behavior is not visible to ordinary Python tooling. The combination of unconditional auto-execution via.pth, deliberate obfuscation, alien-runtime fetch from a non-publisher source, and execution of bundled JavaScript whose contents are opaque to the Python ecosystem constitutes an install/startup-time remote code execution surface against any installer.

Source: kam193 (3bc0ad232af6f3dafcf2d02441531485e0b459c2659542375c62f4f7003c9e08)

Versions 0.1.1, 0.1.2 were compromised.

Compromised packages start an obfuscated infostealer. The infostealer is a heavily obfuscated JavaScript code executed using Bun runtime on Python startup. It collectes all kinds of sensitive data, including API keys, credentials to package repositories, cryptocurrency assets, password manager data. Infostealer actively queries online services to collect additional secrets as well as attempts to gain persistence and spread further by publishing infected packages using collected credentials. Data are exfiltrated likely using Github. The code seems to threaten to wipe the user's data if it detects invalid GitHub tokens. Cleanup should be done with caution.

It seems to be related to the recent Mini Shai Hulud campaign.

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Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2026-06-compr-woodpecker

Reasons (based on the campaign):

• compromised-package

• exfiltration-env-variables

• exfiltration-cloud-tokens

• exfiltration-credentials

• abuses-pth

• obfuscation

• infostealer

• The package contains code to detect if it is running in a sandbox environment.

• exfiltration-crypto

• files-exfiltration

• destructive-actions