What does the eacq-core malware do?

On require() of eacq-core, both _helpers.js and lib/telemetry.js download a platform-specific binary from Cloudflare Workers hosts assembled at runtime via string-splitting (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT fallback to *.dl.wel1.ru, write the bytes to /tmp/.cache_ or %TEMP%\dotnet_diag_ .exe, chmod 0755 (via fs['chmod'+'Sync']), and spawn the file detached through '/bin/sh -c &' or 'cmd /c start'. No hash or signature verification is performed and the destinations are unrelated to any legitimate publisher. child_process is loaded through require('child_'+'process') and hostnames are assembled

Which versions of eacq-core are malicious?

The following npm versions of eacq-core are flagged malicious: 35.8.1. Treat any of these as compromised.

How do I remediate eacq-core if I installed it?

eacq-core 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 eacq-core — how do I know if it already compromised me?

If eacq-core 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 eacq-core part of a known attack campaign?

Yes — eacq-core is associated with the IN-MAL-2026-016876 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 eacq-core 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 eacq-core (version 35.8.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging eacq-core across your stack and pipelines.

Malicious package

eacq-corenpm

eacq-core is a confirmed malicious npm package (MAL-2026-13514) that steals credentials and exfiltrates sensitive data (malicious version 35.8.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in eacq-core (npm)

MAL-2026-13514

Immediate action

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

npm uninstall eacq-core

What this malware does

On require() of eacq-core, both helpers.js and lib/telemetry.js download a platform-specific binary from Cloudflare Workers hosts assembled at runtime via string-splitting (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT fallback to *.dl.wel1.ru, write the bytes to /tmp/.cache<rand> or %TEMP%\dotnet_diag_<rand>.exe, chmod 0755 (via fs['chmod'+'Sync']), and spawn the file detached through '/bin/sh -c <path> &' or 'cmd /c start'. No hash or signature verification is performed and the destinations are unrelated to any legitimate publisher. child_process is loaded through require('child_'+'process') and hostnames are assembled via.join('') to evade static analysis. Cover-story comments framing the code as an 'Analytics SDK' with 'opt-out env vars' accompany the payload. The fetch-and-execute chain fires unconditionally at module load, giving whoever controls the Workers hosts arbitrary code execution on any machine that installs or imports this package.

Malicious versions

1 flagged

35.8.1

Indicators of compromise (SHA-256)

b500358c69db5b11d186a6656bd7e20b6ae98cf8f8b437af7b320d511f870761

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 eacq-core (version 35.8.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging eacq-core across your stack and pipelines.
If you installed it — respond
eacq-core 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 eacq-core 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 eacq-core 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. eacq-core on npm has been identified as a malicious package (version 35.8.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-016876

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks eacq-core-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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