Which versions of yajusenpai are malicious?

The following npm versions of yajusenpai are flagged malicious: 8.1.0. Treat any of these as compromised.

How do I remediate yajusenpai if I installed it?

Remove yajusenpai 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 yajusenpai — how do I know if it already compromised me?

If yajusenpai 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 yajusenpai part of a known attack campaign?

Yes — yajusenpai is associated with the GHSA-mvhm-mmxr-j3rj, RLMA-2025-05566, RLUA-2025-06005 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 yajusenpai across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for yajusenpai (version 8.1.0).

Malicious package

yajusenpainpm

Advisory published Oct 15, 2025Updated Dec 2, 2025

yajusenpai is a confirmed malicious npm package (MAL-2025-48416) that executes malicious code on install (malicious version 8.1.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in yajusenpai (npm)

MAL-2025-48416

Immediate action

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

npm uninstall yajusenpai

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

1 flagged

8.1.0

Indicators of compromise (SHA-256)

3c8c389c2867c6ae1d774d817b2608a780eb5a86211df02b4197c62673097242

d04e347ba25bed56106db37523fba998cd1f76075dff4249811b9b663c7de296

211987f4af1233d15f100c5876ef3c5e2b760a76f9b4977fb8f9810d8b2cc4ea

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for yajusenpai (version 8.1.0).
If you installed it — respond
Remove yajusenpai 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 yajusenpai 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. yajusenpai on npm has been identified as a malicious package (version 8.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-mvhm-mmxr-j3rjRLMA-2025-05566RLUA-2025-06005

References

Credits

Amazon Inspector · finder
ReversingLabs · finder

Detect & block this

O3 blocks yajusenpai-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

Explore

All malware advisories How O3 detects malware Vulnerability database