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Malicious package

mypy-extensionsnpm

Advisory published Updated

mypy-extensions is a confirmed malicious npm package (MAL-2024-2685) that executes malicious code on install (malicious versions 0.4.2, 1.0.0, 10.9.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in mypy-extensions (npm)

MAL-2024-2685
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall mypy-extensions

What this malware does

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

3 flagged
0.4.21.0.010.9.0

Indicators of compromise (SHA-256)

312f86ffc41a1f78b55ed52200094d445e4dd9d5ffa7e069c32b4d1a666385c8
ea951beb30537bdb569d89036c534bebcca4ee9158474120c1b3d34911d5b073
10ccf73f6507139e279e97b3fd9abef0395cd75b2f90dd18dde8e6f90753de4d
143a03fd6c8819aac78b6276ce1e092c88256bb3daa296c4a64c74b471f50745
a5372425e20fe6ad71eb38da84883dba8b8b2594943f696d83a77a844b35e2f2

Detection & response playbook

Malicious package
  1. Find it

    Search your lockfiles and build artifacts for mypy-extensions (3 malicious versions).

  2. If you installed it — respond

    Remove mypy-extensions from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

  3. Did it already run?

    If mypy-extensions 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. mypy-extensions on npm has been identified as a malicious package (versions 0.4.2, 1.0.0, 10.9.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2024-01373RLUA-2024-06935GHSA-59pp-xx6g-vrw4RLUA-2025-05433RLUA-2025-05891

References

Credits

  • ReversingLabs · finder

Detect & block this

O3 blocks mypy-extensions-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Explore

mypy-extensions (npm) malicious package — MAL-2024-2685 | O3 Security