npx-oob-packagenpm
Advisory published Updated
npx-oob-package is a confirmed malicious npm package (MAL-2026-15597) that opens a backdoor for remote access (malicious versions 1.0.0, 1.0.1, 1.0.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in npx-oob-package (npm)
What this malware does
npx-oob-package ships bin/cli.js which is also declared as the package main. On both CLI invocation and any require()/import of the package, the module collects local identifiers (whoami / os.userInfo(), os.hostname(), os.platform()) along with the package name and POSTs them via fetch() to a hardcoded Cloudflare Workers endpoint at https://oobme.kunalsharma0553.workers.dev/r/7bq6fz3l15r9. The callback destination is not configurable and there is no user consent or opt-out. The package presents as an out-of-band (OOB) beacon consistent with dependency-confusion or pentest-style reconnaissance, causing installer host and user identifiers to leave the machine to an author-controlled endpoint on install-triggered require or CLI use.
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.
The OpenSSF Package Analysis project identified 'npx-oob-package' @ 1.0.2 (npm) as malicious.
It is considered malicious because:
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The package communicates with a domain associated with malicious activity.
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The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for npx-oob-package (3 malicious versions).
If you installed it — respond
npx-oob-package establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If npx-oob-package 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
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks npx-oob-package-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.