Which versions of calccc are malicious?

The following PyPI versions of calccc are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate calccc if I installed it?

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

If calccc 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 calccc part of a known attack campaign?

Yes — calccc is associated with the 2023-12-valuent 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 calccc across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for calccc (version 1.0.0).

Part of a larger attack: 2023-12-valuent published 17 malicious packages. See the full campaign →

Malicious package

calcccPyPI

Advisory published Nov 30, 2024Updated Dec 12, 2025

calccc is a confirmed malicious PyPI package (MAL-2024-12226) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in calccc (PyPI)

MAL-2024-12226

Immediate action

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

pip uninstall calccc

What this malware does

Packages either test the malicious behaviour, or actually download and run a simple remote script during the installation.

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: 2023-12-valuent

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.
Downloads and executes a remote malicious script.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

dc013333b1f37bacf53b2fcec8a21efa28a7d9320468c74bba4dc14223a66239

66371c79f4cedb638d8d283883415c46a4bf6be25e3699fe5229bc8cd71a2f0a

2ac839a2c2561fb78df54ffbc3c8a2662624c376ad59a6231d8f57dc78cbdcc8

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for calccc (version 1.0.0).
If you installed it — respond
calccc 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 calccc 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. calccc on PyPI has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2023-12-valuent

References

bad-packages.kam193.eu

Credits

Kamil Mańkowski (kam193)

Detect & block this

O3 blocks calccc-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