Which versions of tinymask-js are malicious?

The following npm versions of tinymask-js are flagged malicious: 1.0.2. Treat any of these as compromised.

How do I remediate tinymask-js if I installed it?

Remove tinymask-js from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed tinymask-js — how do I know if it already compromised me?

If tinymask-js 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 tinymask-js part of a known attack campaign?

Yes — tinymask-js is associated with the IN-MAL-2026-009744 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 tinymask-js 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 tinymask-js (version 1.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tinymask-js across your stack and pipelines.

Malicious package

tinymask-jsnpm

Malicious code in tinymask-js (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-10189

Immediate action

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

npm uninstall tinymask-js

What this malware does

index.js (declared as the package main) reconstructs a host, URL paths, and dropped filenames from String.fromCharCode numeric arrays, resolving to https://filament-zap.vercel.app/service/assets/fetchBinary and /fetchLinuxBinary. On require, it downloads an OS-specific binary over HTTPS, writes it to %LOCALAPPDATA%\Programs\WinMetrics\WinService.exe on Windows or ~/.local/share/WinMetrics on Linux, chmods it 0755 on Linux, and spawns it detached with stdio ignored and windowsHide set. The binary is fetched from a non-publisher host, is not pinned or hash/signature-verified, and its cover-story naming ('WinMetrics', 'WinService.exe') is unrelated to the package's advertised input-masking purpose. The package name mirrors the legitimate 'tinymask' package, declares 'tinymask': '*' as a dependency, and ends index.js with module.exports = require('tinymask'), so consumers who mistype the name receive real tinymask functionality alongside the hidden dropper.

Malicious versions

1 flagged

1.0.2

Indicators of compromise (SHA-256)

dc1d083feee4cace9dba5cabdfd74701c7dc093520f0bbc104858ab699203604

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tinymask-js (version 1.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tinymask-js across your stack and pipelines.
If you installed it — respond
Remove tinymask-js from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If tinymask-js 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 tinymask-js 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. tinymask-js on npm has been identified as a malicious package (version 1.0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009744

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks tinymask-js-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