Malicious code in pylogfmt (PyPI)
On import pylogfmt, the package's __init__.py spawns a detached background subprocess (subprocess.Popen([sys.executable, '_check.py'], stdout=DEVNULL, stderr=DEVNULL)) that runs an infinite loop POSTing the package install path to https://pypkg.dev/project/pylogfmt/json every 60 seconds with TLS verification explicitly disabled. The HTTP response body is base64-decoded and dispatched to a worker thread (threading.Thread(target=check, args=(package_list.decode(),))), which is the canonical remote-payload-dispatcher shape — the operator controls returned bytes and the client decodes and feeds them into a handler. The destination domain pypkg.dev is a lookalike of pypi.org/pypa with no relation to the package's declared logging-library purpose. Output suppression (DEVNULL on both streams), undocumented behavior (README advertises only a logging helper), TLS bypass, and lookalike C2 destination together are unambiguous attack signals. Any consumer that imports pylogfmt as a library leaks their install path to attacker infrastructure on a 60-second polling interval and is one server-side change away from arbitrary remote code execution.
Package silently executes remote code during import.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-05-lognest
Reasons (based on the campaign):
MAL-2026-4231 is recorded against 1 package.
Published on 22 May 2026 and last revised on 26 May 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
Domains: pypkg.dev
URLs: https://pypkg.dev/project/logger/json
Details
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| pylogfmt | — | — |
References
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