Which versions of mypy-extensions are malicious?

The following npm versions of mypy-extensions are flagged malicious: 0.4.2, 1.0.0, 10.9.0. Treat any of these as compromised.

How do I remediate mypy-extensions if I installed it?

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.

I already installed mypy-extensions — how do I know if it already compromised me?

If mypy-extensions 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 mypy-extensions part of a known attack campaign?

Yes — mypy-extensions is associated with the RLMA-2024-01373, RLUA-2024-06935, GHSA-59pp-xx6g-vrw4, RLUA-2025-05433, RLUA-2025-05891 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 mypy-extensions 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 mypy-extensions (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging mypy-extensions across your stack and pipelines.

Malicious package

mypy-extensionsnpm

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

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for mypy-extensions (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging mypy-extensions across your stack and pipelines.
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.
Did it already run?
If mypy-extensions 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 mypy-extensions 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. 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.

Malware detection Runtime egress monitoring

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