pymem-winPyPI
Advisory published Updated
pymem-win is a confirmed malicious PyPI package (MAL-2026-16128) that steals credentials and exfiltrates sensitive data (malicious versions 1.14.0, 1.14.1, 1.14.4…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in pymem-win (PyPI)
What this malware does
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.
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):
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obfuscation
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Downloads and executes a remote executable.
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clones-real-package
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for pymem-win (5 malicious versions).
If you installed it — respond
pymem-win is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If pymem-win was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- Kamil Mańkowski (kam193) · reporter
Detect & block this
O3 blocks pymem-win-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.