Which versions of sjs-biginteger are malicious?

The following npm versions of sjs-biginteger are flagged malicious: 5.0.5, 5.0.6. Treat any of these as compromised.

How do I remediate sjs-biginteger if I installed it?

sjs-biginteger 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 sjs-biginteger — how do I know if it already compromised me?

If sjs-biginteger was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Is sjs-biginteger part of a known attack campaign?

Yes — sjs-biginteger is associated with the GHSA-38ww-f26r-f8w7 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 sjs-biginteger across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for sjs-biginteger (2 malicious versions).

Malicious package

sjs-bigintegernpm

Advisory published Apr 9, 2026Updated Jul 6, 2026

sjs-biginteger is a confirmed malicious npm package (MAL-2026-2527) that steals credentials and exfiltrates sensitive data (malicious versions 5.0.5, 5.0.6). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in sjs-biginteger (npm)

MAL-2026-2527

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall sjs-biginteger

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-biginteger 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

2 flagged

5.0.55.0.6

Indicators of compromise (SHA-256)

ad825f5a8f4892374c8e1f8a4d1e5e84e28419eb656035667c4c9d8964966f6d

fcae78c041d8a88f2709f71788ac5b4e4e5f5f17862874f05e4a3742e9f4f464

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for sjs-biginteger (2 malicious versions).
If you installed it — respond
sjs-biginteger 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-biginteger was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. sjs-biginteger on npm has been identified as a malicious package (versions 5.0.5, 5.0.6 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-38ww-f26r-f8w7

References

Credits

Amazon Inspector · finder
SafeDep · finder

Detect & block this

O3 blocks sjs-biginteger-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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