postcss-animate-css-varsnpm
postcss-animate-css-vars is a confirmed malicious npm package (MAL-2026-12418) that executes malicious code on install (malicious versions 1.0.0, 2.0.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in postcss-animate-css-vars (npm)
What this malware does
src/normalize-options.js is heavily obfuscated (RC4-decoded string array, hex-numeric literals, rotating string-array shuffler, dead-code comparison branches) while the rest of the package (index.js, plugin.js, root.js, declarations.js) is plain readable code. When the PostCSS plugin is instantiated (createPlugin -> normalizeOptions), the loader assembles an HTTPS URL from obfuscated string-array entries, appends keys from the caller-supplied options.features sub-object as query parameters, fetches a JSON response, base64-decodes its message field, and executes the decoded code with new Function('require', code)(require) — arbitrary code execution in every downstream consumer's build/CI process. The loader also writes a wrapper file to the OS tmpdir (named with process.pid) containing require('<pkg>')(<options>); setInterval(()=>{},2147483647); and spawns process.execPath detached with stdio ignored and env LT1_STAGE1_CHILD=1, then calls child.unref(). The detached node child re-enters the loader branch, decoupling the fetch-and-eval from the parent build and keeping it alive on a ~24.8-day interval after PostCSS exits, enabling persistent staging beyond the build window. Package metadata (name postcss-animate-css-vars, description 'PostCSS plugin for animate.css', author 'Alex Rivera [email protected]', homepage cssanimation.dev) presents as a legitimate PostCSS ecosystem plugin, but the shipped code contains no animate.css handling in the obfuscated loader path — the metadata is cover for the loader.
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
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for postcss-animate-css-vars (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging postcss-animate-css-vars across your stack and pipelines.
If you installed it — respond
Remove postcss-animate-css-vars 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.
Did it already run?
If postcss-animate-css-vars 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.
How O3 protects you
O3 blocks postcss-animate-css-vars 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks postcss-animate-css-vars-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.