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, GHSA-26h4-2435-hp66 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

eth-base is a confirmed malicious npm package (MAL-2026-10413) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in eth-base (npm)

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.

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

1.0.0

Indicators of compromise (SHA-256)

bcc98bc680f3d0b8c6dcf396d9f2425a5153658259014384cedf82698413755b

41bca5a4bf7e0ef4a8bb255ed20cefe3835b2b015efed111ce1f87584b285ac6

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-2026-009837GHSA-26h4-2435-hp66

References

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

Explore

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