Which versions of yakuza0 are malicious?

The following npm versions of yakuza0 are flagged malicious: 2.23.40, 2.23.40-beta.3. Treat any of these as compromised.

How do I remediate yakuza0 if I installed it?

yakuza0 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 yakuza0 — how do I know if it already compromised me?

If yakuza0 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 yakuza0 part of a known attack campaign?

Yes — yakuza0 is associated with the IN-MAL-2026-017066, IN-MAL-2026-017067 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 yakuza0 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 yakuza0 (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging yakuza0 across your stack and pipelines.

Malicious package

yakuza0npm

yakuza0 is a confirmed malicious npm package (MAL-2026-13605) that steals credentials and exfiltrates sensitive data (malicious versions 2.23.40, 2.23.40-beta.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in yakuza0 (npm)

MAL-2026-13605

Immediate action

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

npm uninstall yakuza0

What this malware does

The package ships code that binds outbound network calls to a hardcoded non-standard host, https://registry-pxnpm.rdc.nfjbill.ren, from cli/index.js (fetch calls at lines 513, 554, 623 alongside a reference to process.versions for host fingerprinting). Additional files server/proxy/tire.js and server/proxy/csrf.js combine child_process usage with curl-based POST/GET operations, mixing shell command execution with outbound HTTP to non-registry endpoints. The destination host is not the npm registry or a documented publisher domain; its name mimics the format of a private npm registry, and it is invoked from top-level module code paths rather than a user-invoked API. The composition — hardcoded attacker-shaped endpoint, runtime process/version fingerprinting, curl-driven POSTs, and child_process shell execution wired to the same network paths — matches the shape of installer-targeted exfiltration and remote command execution.

Malicious versions

2 flagged

2.23.402.23.40-beta.3

Indicators of compromise (SHA-256)

74b981d7ed2585510333eff3e9be65daeadbd89632d873097b25b54f5c340ee4

c9952a92dd18e2353ebb4f2d8064884e7be770d23770096af6dbe1844d8b5fd6

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for yakuza0 (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging yakuza0 across your stack and pipelines.
If you installed it — respond
yakuza0 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 yakuza0 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 yakuza0 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. yakuza0 on npm has been identified as a malicious package (versions 2.23.40, 2.23.40-beta.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-017066IN-MAL-2026-017067

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks yakuza0-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

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