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Malicious package

pfa-prettier-confignpm

Advisory published Updated

pfa-prettier-config is a confirmed malicious npm package (MAL-2026-12407) that executes malicious code on install (malicious version 20.9.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in pfa-prettier-config (npm)

MAL-2026-12407
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall pfa-prettier-config

What this malware does

The package is published as 'pfa-prettier-config' with description 'environment config reader', but contains no Prettier configuration or config-reading code. index.js unconditionally requires./platform on load. platform.js selects a per-OS asset path, fetches bytes from one of four Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev) — with hostnames reassembled at runtime via string-concat (e.g. ["oob-worker.cf","102-baf.workers.dev"].join("")) — and falls back to a chunked DNS TXT download from tin.dl.well1.site. The fetched bytes are written to /var/tmp/.cache<hex> or %TEMP%/dotnet_diag<hex>.exe under cover names, chmod'd 0755, and spawned detached via cp.spawn('/bin/sh', ['-c', fp+' &'], {detached:true}).unref() or spawn('cmd',...). A second dropper is shipped in lib/telemetry.js (~81KB, disguised as an 'Analytics SDK') containing the same primitives (base64 chunk decode, chmodSync 0755 on 'extensionPath', cp.spawn('/bin/sh', ['-c', filePath+' &'])), with child_process required via the computed string require('child_'+'process'). Requiring or importing this package triggers download-and-execute of an attacker-hosted OS-specific binary.

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
20.9.1

Indicators of compromise (SHA-256)

08f4b65c7534427cd8814e8c85a84b11c2201d10724c34bb99987bae83e0c5cc
3d367f5160b47afe3e72f884621b4a8f8946a3a07dfcd5c4c9fbd659c57a2b2a

Detection & response playbook

Malicious package
  1. Find it

    Search your lockfiles and build artifacts for pfa-prettier-config (version 20.9.1).

  2. If you installed it — respond

    Remove pfa-prettier-config 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 pfa-prettier-config 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. pfa-prettier-config on npm has been identified as a malicious package (version 20.9.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014774GHSA-qmmm-73xw-c3f2

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks pfa-prettier-config-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

pfa-prettier-config (npm) malicious package — MAL-2026-12407 | O3 Security