What does the eth-base malware do?

The published lib/index.js contains ~60KB of obfuscated JavaScript appended after a copy of the legitimate web3.js web3-core-subscriptions module. On require(), the appended IIFE loads axios, issues an HTTPS request to a URL reconstructed at runtime from custom base-85 alphabets, and on a specific response constructs `new Function('require', )(require)` to execute attacker-supplied JavaScript in-process with full Node require access. The corresponding src/index.js is the clean upstream module, indicating the payload was injected only into the shipped build. The package name and description impersonate a web3.js helper (LGPL header still credits Fabian Vogelsteller <fabian@ether

Which versions of eth-base are malicious?

The following npm versions of eth-base are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate eth-base if I installed it?

eth-base 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 eth-base — how do I know if it already compromised me?

If eth-base 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 eth-base part of a known attack campaign?

Yes — eth-base is associated with the IN-MAL-2026-009837 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 eth-base 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 eth-base (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging eth-base across your stack and pipelines.

Malicious package

eth-basenpm

Malicious code in eth-base (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-10413

Immediate action

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

npm uninstall eth-base

What this malware does

The published lib/index.js contains ~60KB of obfuscated JavaScript appended after a copy of the legitimate web3.js web3-core-subscriptions module. On require(), the appended IIFE loads axios, issues an HTTPS request to a URL reconstructed at runtime from custom base-85 alphabets, and on a specific response constructs new Function('require', <remote-token>)(require) to execute attacker-supplied JavaScript in-process with full Node require access. The corresponding src/index.js is the clean upstream module, indicating the payload was injected only into the shipped build. The package name and description impersonate a web3.js helper (LGPL header still credits Fabian Vogelsteller [email protected]) while the repository field is empty. Consumers who require this package receive arbitrary code execution on the installing host at load time.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

bcc98bc680f3d0b8c6dcf396d9f2425a5153658259014384cedf82698413755b

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 eth-base (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging eth-base across your stack and pipelines.
If you installed it — respond
eth-base 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 eth-base 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 eth-base 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. eth-base on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009837

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks eth-base-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