Malicious code in sigchain-js (npm)
Malicious code was injected into the published npm package sigchain-js, executing arbitrary code on installation via DES-decrypted payloads from companion packages thedata and tchain-api. The attack also involved typosquatting axios to version 1.18.1, which does not exist in legitimate release history.
- Disclosed
- Last updated
- Blast radius
- Any developer or system that installed sigchain-js from npm; arbitrary code execution on installation.
- Ecosystems
- Attack vectors
- Affected entities
- sigchain-jsPublished dist bundles contain malicious code not present in source
- thedataCompanion package supplying encrypted payload for ESM build
- tchain-apiLook-alike package supplying rsa.db file for CJS/UMD builds
- axiosPinned to non-existent version 1.18.1, redirecting to typosquatted package
The npm package sigchain-js contained malicious code in its published distribution bundles (dist/sigchain-js.cjs.js, dist/sigchain-js.esm.js, dist/sigchain-js.umd.js) that was not present in the source tree. The code reads encrypted payloads from companion packages, decrypts them using a hardcoded password ("hydra"), and executes the decrypted content via a spawned Node.js subprocess.
The attack was distributed across multiple cooperating packages: the thedata package (a direct dependency) supplied the encrypted payload for the ESM build, while tchain-api (a look-alike of Theta's official API SDK, pulled in transitively) supplied an rsa.db file for the CJS/UMD builds. The malicious code included top-level imports of child_process, node:fs, node:path, and (for ESM) desKey from thedata that do not exist in the published source.
Additionally, sigchain-js pinned axios to version 1.18.1, a version that does not exist in the legitimate axios release history, redirecting installers to a typosquatted package. Requiring or importing sigchain-js resulted in arbitrary code execution on the installer's host, with the executed content controlled by whoever published updates to the companion packages.
Indicators of compromise
- Packages
- sigchain-js
- thedata
- tchain-api
- axios@1.18.1
- Hashes
- 034ba6bdd11139e40b062606dfa180a60727249035899eded96d34797b63a026
Remediation
- Remove sigchain-js from all projects and dependencies immediately
- Audit npm install logs and package-lock.json files to identify when sigchain-js was installed
- Review and revoke any credentials, tokens, or secrets that may have been exposed on affected systems
- Scan affected systems for signs of compromise or persistence mechanisms
- Update axios to a legitimate version from the official npm registry
- Review all transitive dependencies for unexpected or suspicious packages (e.g., tchain-api)
- Implement package pinning and integrity verification (e.g., npm audit, lock files) in CI/CD pipelines
Sources
- GitHub Advisory GHSA-j78w-wm55-982q · GitHub Advisory Database
Cite this entry
"Malicious code in sigchain-js (npm)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed July 28, 2026; last updated July 28, 2026. https://supplychainattack.org/incident/malicious-code-in-sigchain-js-npm-1d2gdi
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