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Malicious package

insomnia-plugin-poc-m4gester-runnpm

Advisory published Updated

insomnia-plugin-poc-m4gester-run is a confirmed malicious npm package (MAL-2026-10493) that typosquats a legitimate package to trick installs (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in insomnia-plugin-poc-m4gester-run (npm)

MAL-2026-10493
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall insomnia-plugin-poc-m4gester-run

What this malware does

package.json declares a postinstall lifecycle hook that runs calc.exe on the installer's machine during npm install. The main entry point exports only an empty requestHooks array, providing no actual Insomnia plugin functionality — the package's sole effect is the arbitrary command execution at install time. The name self-identifies as a proof-of-concept and mimics the Insomnia plugin naming convention with a leet-substituted variant, indicating the package exists solely to demonstrate/exploit install-time RCE. While calc.exe itself is benign, the postinstall hook establishes full arbitrary-command-execution capability against any developer installing the package on Windows.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

38a525aea57681df6c21035b723701fa6067f091fd81ac26bb3fcc8e2126c43e

Detection & response playbook

Typosquat
  1. Find it

    Search your lockfiles and build artifacts for insomnia-plugin-poc-m4gester-run (version 1.0.0).

  2. If you installed it — respond

    insomnia-plugin-poc-m4gester-run is a typosquat — you almost certainly intended a legitimately-named package. Remove insomnia-plugin-poc-m4gester-run, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

  3. Did it already run?

    If insomnia-plugin-poc-m4gester-run 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. insomnia-plugin-poc-m4gester-run 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-2026-010318

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks insomnia-plugin-poc-m4gester-run-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.

Explore

insomnia-plugin-poc-m4gester-run (npm) malicious package — MAL-2026-10493 | O3 Security