Which versions of s4transfer are malicious?

The following PyPI versions of s4transfer are flagged malicious: 0.3. Treat any of these as compromised.

How do I remediate s4transfer if I installed it?

s4transfer 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 s4transfer — how do I know if it already compromised me?

If s4transfer 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.

Is s4transfer part of a known attack campaign?

Yes — s4transfer is associated with the RLMA-2024-11157, GENERIC-standard-pypi-install-pentest, RLUA-2026-00743 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 s4transfer across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for s4transfer (version 0.3).

Malicious package

s4transferPyPI

Advisory published Jul 26, 2024Updated Mar 19, 2026

s4transfer is a confirmed malicious PyPI package (MAL-2024-11699) that steals credentials and exfiltrates sensitive data (malicious version 0.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in s4transfer (PyPI)

MAL-2024-11699

Immediate action

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

pip uninstall s4transfer

What this malware does

Installing the package or importing the module exfiltrates basic information about the host, and the package has no other purpose.

Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.

Campaign: GENERIC-standard-pypi-install-pentest

Reasons (based on the campaign):

The package contains code to exfiltrate basic data from the system, like IP or username. It has a limited risk.
The package overrides the install command in setup.py to execute malicious code during installation.

Malicious versions

1 flagged

0.3

Indicators of compromise (SHA-256)

019d1080d3f7112dd28dccab107891d2825fdf8e62d06c037018a83eb46ed60d

4efcd735294f92c18d485f257e948a7a5db98f26a5c69d9ff37bf6ea581cde9d

18c14c40902edbe0bd3c62c1b43d3074b28c6c717d6c2522e0df56ed88643fcb

4dc0b3ee3f40f75c5d5316b72ce00849293d50cb6ce11c6ff4b70e55071fedaa

4e5b54840e5613490d8dd81dcfbd225506417dc723b2b07f79fefe29a6cf874a

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for s4transfer (version 0.3).
If you installed it — respond
s4transfer 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 s4transfer 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

No. s4transfer on PyPI has been identified as a malicious package (version 0.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2024-11157GENERIC-standard-pypi-install-pentestRLUA-2026-00743

References

bad-packages.kam193.eu

Credits

Kamil Mańkowski (kam193)
ReversingLabs · finder

Detect & block this

O3 blocks s4transfer-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

Explore

All malware advisories How O3 detects malware Vulnerability database