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Malicious package

simple-node-calc-anpm

Advisory published Updated

simple-node-calc-a is a confirmed malicious npm package (MAL-2026-6451) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in simple-node-calc-a (npm)

MAL-2026-6451
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall simple-node-calc-a

What this malware does

[email protected] advertises itself as a pure-JS calculator but ships a binding.gyp that triggers node-gyp automatically during npm install. binding.gyp line 6 uses gyp's shell-expansion directive "<!(node lodash-compiler.js && echo stub.c)", which executes the sibling file lodash-compiler.js in the installer's environment at configure time, before any user code runs. lodash-compiler.js is an 87 KB obfuscator.io-packed file (rotated 510-entry _0x string array, control-flow flattening, 2906 deobfuscation transforms) presented with a lodash custom-build banner but never declared as a dependency and never imported by index.js. The deobfuscated trailer resolves to require('fs').writeFileSync('poc.txt', 'POC...'), writing a file into the installer's current working directory outside the package's own folder. The combination — undocumented native-build hook in a package with no native code, heavily obfuscated payload reachable only via that hook, and a write to the installer's CWD — is a working install-time arbitrary-code-execution primitive. Today's payload drops a PoC marker file; the same channel can deliver any code the author chooses on subsequent versions.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

f9a86d4aeac1d4f5fc458b3058f4b13229cd2097c9d8e5cf3e4d45aa24980ad8

Detection & response playbook

Malicious package

  1. Find it

    Search your lockfiles and build artifacts for simple-node-calc-a (version 1.0.0).

  2. If you installed it — respond

    Remove simple-node-calc-a 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.

  3. Did it already run?

    If simple-node-calc-a 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. simple-node-calc-a 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-2026-007505

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks simple-node-calc-a-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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simple-node-calc-a (npm) malicious package — MAL-2026-6451 | O3 Security