eth-codergennpm
eth-codergen is a confirmed malicious npm package (MAL-2026-11033) that executes malicious code on install (malicious versions 1.0.0, 1.0.1, 1.0.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in eth-codergen (npm)
What this malware does
The package is advertised as an Ethereum ABI code generator but its index.js is a verbatim copy of the unrelated mongoose-lean-hooks plugin. Appended to the same line as module.exports = leanhooksPlugin; (padded with whitespace to push it off-screen) is a top-level Function("tQ4eR5v",...) call whose body is a custom hex/XOR-mixer decoder (constants 0x9e3779b9, 0x243f6a88, 0x6a09e667) that reconstructs an opaque payload from an encoded byte array and executes it. The obfuscated loader runs automatically whenever a consumer calls require('eth-codergen'), giving the publisher arbitrary code execution in the consumer's Node.js process. The package name differs by one letter from the legitimate eth-codegen package, and the README even instructs npm install --save-dev eth-codegen, indicating the package is positioned to catch developers who mistype the real package name. No Ethereum/ABI codegen functionality is present in the shipped code.
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
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for eth-codergen (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging eth-codergen across your stack and pipelines.
If you installed it — respond
Remove eth-codergen 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 eth-codergen 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-codergen 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks eth-codergen-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.