postcss-motion-utilsnpm
postcss-motion-utils is a confirmed malicious npm package (MAL-2026-11168) that executes malicious code on install (malicious version 3.2.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in postcss-motion-utils (npm)
What this malware does
Package is advertised as a small PostCSS plugin that injects CSS variables and adds -webkit- prefixes, but its main (index.js) is a 164 KB single-file Bun-bundled artifact wrapped in a bytecode-VM obfuscator: a rotated string array (vmZ) with a shift-based decoder, a VM interpreter (vmT_21dbca), and a payload table of ~20 large base64 blobs, several of which decode to opaque binary-shaped bytes. The file begins with the // @bun header and a while(!![]) string-array rotation loop. Because this file is the module main, the VM and its embedded payloads execute on require('postcss-motion-utils'). The declared PostCSS functionality does not require bytecode-VM obfuscation or embedded binary blobs; the shape (opaque decoder + rotated string array + base64-encoded inner payloads executed at import) matches the structure of hidden supply-chain payloads rather than a CSS utility library.
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-motion-utils (version 3.2.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging postcss-motion-utils across your stack and pipelines.
If you installed it — respond
Remove postcss-motion-utils 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-motion-utils 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-motion-utils 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-motion-utils-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.