umber-rootnpm
umber-root is a confirmed malicious npm package (MAL-2026-12814) that executes malicious code on install (malicious versions 1.1.0, 1.1.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in umber-root (npm)
What this malware does
The npm postinstall lifecycle hook runs dist/config.js, which fetches JSON from https://my-api.trade-api.workers.dev?id=3 and then invokes globalThis[data.success](data.id), letting the remote endpoint choose which global (eval, Function, require, etc.) to call and with what argument. The package reassigns globalThis.require = require earlier in the same file to make require reachable through this indirection. The result is arbitrary code execution on every installer machine during npm install, with both the executor and its argument supplied by an attacker-controlled Cloudflare Workers endpoint. The package advertises itself as a color toolkit; there is no build or configuration purpose served by a network-dispatched global invocation, and the string-indexed global lookup is an evasion pattern that hides the sink from static scanners.
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 umber-root (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging umber-root across your stack and pipelines.
If you installed it — respond
Remove umber-root 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 umber-root 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 umber-root 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 umber-root-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.