MAL-2026-5300 Malicious code in funcdesc (PyPI)

The package installs funcdesc-setup.pth, which Python auto-executes at interpreter startup for any environment where this package is installed. The.pth file is obfuscated with single-letter aliases (_O, _T, _G, _o, _s, _u,…) and wraps its real payload in exec() over an inline string, gated by a /tmp/.bun_ran sentinel. On first run it calls urllib.request.urlretrieve to download the Bun JavaScript runtime release archive from https://github.com/oven-sh/bun/releases/download/bun-v1.3.13/bun-<platform>-<arch>.zip, extracts it to /tmp/b/bun, chmods it executable, and then invokes bun run _index.js against a bundled _index.js shipped inside the package. The advertised purpose of funcdesc is a Python function-description protocol; there is no legitimate reason for it to fetch and run an alternate JavaScript runtime, stage binaries in /tmp, or execute opaque bundled JS outside the documented Python API. The pattern (auto-loaded.pth, obfuscated exec, alternate-runtime dropper, mismatched purpose, in-file __version__ still reading 0.2.1) is consistent with a hijacked release rather than legitimate maintainer behavior. The harm fires automatically every time a Python interpreter starts in any environment where this version is installed, not only at pip install, giving the attacker arbitrary code execution on the installer's machine.

Versions 0.2.2, 0.2.3 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.

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