Which versions of box-sign-client are malicious?

The following npm versions of box-sign-client are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate box-sign-client if I installed it?

box-sign-client 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 box-sign-client — how do I know if it already compromised me?

If box-sign-client 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 box-sign-client part of a known attack campaign?

Yes — box-sign-client is associated with the IN-MAL-2026-019638 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 box-sign-client across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for box-sign-client (version 1.0.0).

Malicious package

box-sign-clientnpm

Advisory published Sep 4, 2026Updated Sep 4, 2026

box-sign-client is a confirmed malicious npm package (MAL-2026-15920) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in box-sign-client (npm)

MAL-2026-15920

Immediate action

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

npm uninstall box-sign-client

What this malware does

[email protected] is a dependency-confusion vehicle positioned against the internal Box namespace (@box/sign-client). Its package.json declares a preinstall script (node index.js) that reads os.hostname() and process.env.USER/USERNAME, embeds those values into a subdomain of the hardcoded host iv6mfybhp42k33ysmzi73de5w.canarytokens.com, and calls dns.resolve() to trigger a DNS lookup against that subdomain. On any npm install that resolves this public package instead of the intended internal one, the installing host's hostname and login user are transmitted via DNS to a third-party Canarytokens collector at install time, before any application code is run. The package advertises itself as a proof-of-concept for Box dependency confusion, but the beacon fires against any installer regardless of intent.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

76143eab11057809af00414cb665446366f039e3cbf1fa82aae06a1093cbbf49

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for box-sign-client (version 1.0.0).
If you installed it — respond
box-sign-client 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 box-sign-client 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. box-sign-client on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-019638

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks box-sign-client-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

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