Which versions of pylogfmt are malicious?

The following PyPI versions of pylogfmt are flagged malicious: 0.1.0. Treat any of these as compromised.

How do I remediate pylogfmt if I installed it?

pylogfmt 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.

I already installed pylogfmt — how do I know if it already compromised me?

If pylogfmt was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is pylogfmt part of a known attack campaign?

Yes — pylogfmt is associated with the 2026-05-lognest, IN-MAL-2026-004107 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find pylogfmt across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for pylogfmt (version 0.1.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging pylogfmt across your stack and pipelines.

Malicious package

pylogfmtPyPI

Malicious code in pylogfmt (PyPI) Remove it immediately and rotate any exposed credentials.

MAL-2026-4231

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

pip uninstall pylogfmt

What this malware does

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):

Downloads and executes a remote malicious script.

Malicious versions

1 flagged

0.1.0

Indicators of compromise (SHA-256)

ba18f7e82fa8d07985ef44f6ce5a8d4b7759f2e348b6ba073bba4dd463740d8e

34bc39125496330ed9b38f1f6d7f06db7e150d83144f9d7e1e04552112851c4a

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for pylogfmt (version 0.1.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging pylogfmt across your stack and pipelines.
If you installed it — respond
pylogfmt 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 pylogfmt was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks pylogfmt before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. pylogfmt on PyPI has been identified as a malicious package (version 0.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2026-05-lognestIN-MAL-2026-004107

References

Credits

Amazon Inspector · finder
Kamil Mańkowski (kam193) · reporter

Detect & block this

O3 blocks pylogfmt-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring