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Part of a larger attack: 2025-06-atlasctf published 23 malicious packages. See the full campaign →
Malicious package

atlasctf-21-prod-16PyPI

Advisory published Updated

atlasctf-21-prod-16 is a confirmed malicious PyPI package (MAL-2025-6453) that steals credentials and exfiltrates sensitive data (malicious versions 99.99.99, 99.99.99.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in atlasctf-21-prod-16 (PyPI)

MAL-2025-6453
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
pip uninstall atlasctf-21-prod-16

What this malware does

On installation or importing, the package attempts to exfiltrate some basic information, e.g. /etc/passwd

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: 2025-06-atlasctf

Reasons (based on the campaign):

  • exfiltration-generic

  • 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

2 flagged
99.99.9999.99.99.1

Indicators of compromise (SHA-256)

5b29bfc6e361bd5ae424d9b3b0ae26757a0fe30089eec8126764775a9b588e3b
a7d8358425455cb497d72b6abf91196967dac601763c7f54cb113c8cb18fe0dd
57c6acfcb3c6bb659cac9b311e2cc25e72f3ab57d80e3403b70b7e05a2a06ed9
559d0b13a9920c3186c0a3bfe89171fc66133df85892cac538b6b08c66072fff
6c094d1f515b8eaaeb3dffce98bde12d77536bf8eb3854f45d6113e1d15c5217

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for atlasctf-21-prod-16 (2 malicious versions).

  2. If you installed it — respond

    atlasctf-21-prod-16 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.

  3. Did it already run?

    If atlasctf-21-prod-16 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. atlasctf-21-prod-16 on PyPI has been identified as a malicious package (versions 99.99.99, 99.99.99.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2025-035382025-06-atlasctfRLUA-2026-00111

References

Credits

  • Kamil Mańkowski (kam193)
  • ReversingLabs · finder

Detect & block this

O3 blocks atlasctf-21-prod-16-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
atlasctf-21-prod-16 (PyPI) malicious package — MAL-2025-6453 | O3 Security