Malicious code in pymem-win (PyPI)

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Source: amazon-inspector (4c611131ac135f4608698ce56eebd7dc89623b591510a050f2059369c9d51bbf)

Pymem-win is a near-verbatim copy of the legitimate upstream Pymem package (reusing its description, repository URL github.com/srounet/Pymem, and author identity Fabien Reboia [email protected]) republished under a confusable name. The top-level pymem/init.py contains a one-line loader that reverses a bytes literal, base64-decodes it, zlib-decompresses it, and passes the result to exec(). This runs unconditionally on import pymem, handing full in-process code execution to a payload deliberately hidden behind three stacked transforms. The multi-layer obfuscation around an exec target has no legitimate purpose in a library import path; combined with the typosquat cover story that reuses the upstream author's identity, the package's function on install/import is to run attacker-chosen code inside any process that imports it.

Source: kam193 (82eb1f11c9b56a2f2c3e97530db43ef94784a2c75697223828403927b0528477)

During import, the obfuscated code downloads and executes an executable. The remote executable did not exist during analysis, but the repository used to host it overlaps with previous campaign 2026-07-yt-api-dlp

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

Campaign: 2026-09-pymem-win

Reasons (based on the campaign):

• obfuscation

• Downloads and executes a remote executable.

• clones-real-package