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Malicious package

devplatform-vite-plugin-preserve-css-modulesnpm

devplatform-vite-plugin-preserve-css-modules is a confirmed malicious npm package (MAL-2026-13274) that typosquats a legitimate package to trick installs (malicious version 35.6.8). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in devplatform-vite-plugin-preserve-css-modules (npm)

MAL-2026-13274
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall devplatform-vite-plugin-preserve-css-modules

What this malware does

On require() of the package, index.js loads loader.js which selects a platform-specific endpoint, downloads a native binary over HTTPS from string-split-obfuscated hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS TXT covert-channel fallback to sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, writes it to /var/tmp or %TEMP% under a disguised name (.cache<rnd> on Unix, dotnet_diag_<rnd>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. Execution is gated by a /tmp/.analytics_state TTL marker. Destination hostnames are assembled at runtime from split-string fragments to evade source-level review. The package name mimics an internal-sounding vite plugin but the shipped code fetches and executes an arbitrary native binary on the installer's machine at first require().

Malicious versions

1 flagged
35.6.8

Indicators of compromise (SHA-256)

0781a29416d218a9767f37894e3ad9a851110f50693a4bcb1ab6bd168e1f6feb

Detection & response playbook

Typosquat

  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for devplatform-vite-plugin-preserve-css-modules (version 35.6.8). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging devplatform-vite-plugin-preserve-css-modules across your stack and pipelines.

  2. If you installed it — respond

    devplatform-vite-plugin-preserve-css-modules is a typosquat — you almost certainly intended a legitimately-named package. Remove devplatform-vite-plugin-preserve-css-modules, 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 devplatform-vite-plugin-preserve-css-modules 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 devplatform-vite-plugin-preserve-css-modules 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. devplatform-vite-plugin-preserve-css-modules on npm has been identified as a malicious package (version 35.6.8 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015718

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks devplatform-vite-plugin-preserve-css-modules-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.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
devplatform-vite-plugin-preserve-css-modules (npm) malicious package — MAL-2026-13274 | O3 Security