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Malicious package

postinstall-logger-7x9znpm

postinstall-logger-7x9z is a confirmed malicious npm package (MAL-2026-5738) 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 postinstall-logger-7x9z (npm)

MAL-2026-5738
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall postinstall-logger-7x9z

What this malware does

On install, package.json's postinstall hook ("postinstall": "node run.js") triggers execution of bundled beacon scripts (beacon15.js and beacon_linux.js). These scripts pull in child_process, os, and http modules and issue outbound HTTP GET/POST requests carrying host identifiers including os.hostname() and os.platform(). The combination of automatic execution at install time, host-information collection, and outbound HTTP requests to a hardcoded destination is the canonical install-time exfiltration beacon shape. Any developer or CI system running npm install for this package will silently leak host data and execute code from the bundled scripts under the installing user's privileges.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

6e89b603ffc718873a9d4c42167bf0c667c995cc2547bc9b99373ad4e9f0ca1e
7bd01e5566ec604864f993b9387139fdf2145f9f9ffbb9a255e1a9947441a454
e91d5c0b2a31907feedaf2f7c1e590bf3a18e7315f534c41cb684bdafe8c6a4f

Detection & response playbook

Credential / info stealer
  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for postinstall-logger-7x9z (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging postinstall-logger-7x9z across your stack and pipelines.

  2. If you installed it — respond

    postinstall-logger-7x9z 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.

  3. Did it already run?

    If postinstall-logger-7x9z 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.

  4. How O3 protects you

    O3 blocks postinstall-logger-7x9z 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. postinstall-logger-7x9z 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-2026-006339IN-MAL-2026-006340GHSA-j5hw-j4vj-f38v

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks postinstall-logger-7x9z-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Explore

postinstall-logger-7x9z (npm) malicious package — MAL-2026-5738 | O3 Security