Which versions of ensmallen are malicious?

The following PyPI versions of ensmallen are flagged malicious: 0.8.101. Treat any of these as compromised.

How do I remediate ensmallen if I installed it?

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

If ensmallen 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 ensmallen part of a known attack campaign?

Yes — ensmallen is associated with the 2026-06-compr-woodpecker, IN-MAL-2026-008842 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 ensmallen 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 ensmallen (version 0.8.101). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging ensmallen across your stack and pipelines.

Malicious package

ensmallenPyPI

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

MAL-2026-5315

Immediate action

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

pip uninstall ensmallen

What this malware does

The package was found to contain malicious code or consuming dependency that contains malicious code

Versions 0.8.101 were compromised.

Compromised packages start an obfuscated infostealer. The infostealer is a heavily obfuscated JavaScript code executed using Bun runtime on Python startup. It collectes all kinds of sensitive data, including API keys, credentials to package repositories, cryptocurrency assets, password manager data. Infostealer actively queries online services to collect additional secrets as well as attempts to gain persistence and spread further by publishing infected packages using collected credentials. Data are exfiltrated likely using Github. The code seems to threaten to wipe the user's data if it detects invalid GitHub tokens. Cleanup should be done with caution.

It seems to be related to the recent Mini Shai Hulud campaign.

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

Campaign: 2026-06-compr-woodpecker

Reasons (based on the campaign):

compromised-package
exfiltration-env-variables
exfiltration-cloud-tokens
exfiltration-credentials
abuses-pth
obfuscation
infostealer
The package contains code to detect if it is running in a sandbox environment.
exfiltration-crypto
files-exfiltration
destructive-actions

Malicious versions

1 flagged

0.8.101

Indicators of compromise (SHA-256)

f844af5d6142ffdd36c3697ff26feabb3d79b6f75e5ac403d2ade6460023e04c

3c6c422edc088f6a32a62b1b00176ff3533cba5ed0348b5995a9ed00dc5d3e65

dad59933069ee649fd7762c6e22fd60e60a2edde36641aede10db352c9ba5980

a05cd4ff9f8142405c5672f1ffa54d575165f6bc2b0f5324c9bfacf75e651de8

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 ensmallen (version 0.8.101). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging ensmallen across your stack and pipelines.
If you installed it — respond
ensmallen 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 ensmallen 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 ensmallen 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. ensmallen on PyPI has been identified as a malicious package (version 0.8.101 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2026-06-compr-woodpeckerIN-MAL-2026-008842

References

Credits

Amazon Inspector · finder
Kamil Mańkowski (kam193) · analyst

Detect & block this

O3 blocks ensmallen-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