sigchain-jsnpm
sigchain-js is a confirmed malicious npm package (MAL-2026-11146) that executes malicious code on install (malicious versions 1.0.0, 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in sigchain-js (npm)
What this malware does
The published dist bundles (dist/sigchain-js.cjs.js, dist/sigchain-js.esm.js, dist/sigchain-js.umd.js) contain top-level code that reads an encrypted payload from a companion package (esm imports desKey from the thedata package; cjs/umd reads node_modules/tchain-api/apps/docs/app/rsa.db), DES-decrypts it using the hardcoded password "hydra", spawns a detached node child process, and pipes the decrypted string into that subprocess's stdin for execution. This code is not present in the src/ tree — it appears only in the published dist bundles, along with new top-level imports of child_process, node:fs, node:path, and (esm) desKey from thedata that do not exist in source. The dropper is split across cooperating packages: thedata (declared as a direct dependency) supplies the encrypted payload for the esm build, and tchain-api (a look-alike of Theta's official API SDK, pulled in transitively) supplies apps/docs/app/rsa.db for the cjs/umd builds. The package also pins [email protected], a version that does not exist in the legitimate axios release history, redirecting the installer to a squatted namesake. Requiring or importing sigchain-js results in arbitrary code execution on the installer's host, with the executed content controlled by whoever publishes updates to the companion packages.
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 sigchain-js (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging sigchain-js across your stack and pipelines.
If you installed it — respond
Remove sigchain-js 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 sigchain-js 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 sigchain-js 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 sigchain-js-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.