sjs-lint-build1npm
sjs-lint-build1 is a confirmed malicious npm package (MAL-2026-2528) that steals credentials and exfiltrates sensitive data (malicious version 1.0.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in sjs-lint-build1 (npm)
What this malware does
sjs-biginteger typosquats big.js on npm. Published April 7, 2026 by throwaway account vanes.s.p.orit.a, the package ships legitimate big.js source and hides its payload in a dependency: sjs-lint-build1. On install, the dependency’s postinstall hook fetches the attacker’s SSH public key from a C2 server, appends it to ~/.ssh/authorized_keys, opens firewall port 22, then collects SSH keys, environment variables, config files (.env, Solana id.json, config.toml), and system fingerprints. It exfiltrates the collected data to two Vercel-hosted C2 domains disguised as Cloudflare services.
The package sjs-lint-build1 was found to contain malicious 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
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for sjs-lint-build1 (version 1.0.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging sjs-lint-build1 across your stack and pipelines.
If you installed it — respond
sjs-lint-build1 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 sjs-lint-build1 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 sjs-lint-build1 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
- SafeDep · finder
Detect & block this
O3 blocks sjs-lint-build1-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.