wsh4-nmpnpm
Advisory published Updated
wsh4-nmp is a confirmed malicious npm package (MAL-2026-6792) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in wsh4-nmp (npm)
What this malware does
package.json declares scripts.postinstall = 'node index.js'. On install, index.js unconditionally POSTs installer-identifying data — the absolute __filename path (which reveals the OS username and home-directory layout), Node version, process.platform, and process.arch — to a hardcoded Discord webhook (discord.com/api/webhooks/1523336123319849031/...) controlled by the author. The beacon fires automatically at npm install with no consent, no opt-out, and no documented purpose disclosed to the installer. Package naming ('wsh4-nmp') and internal defaults ('whs4_typo') together with a README note about notifying on typos indicate the package is positioned as a typosquat probe whose function is to inform the author whenever an installer mistypes a target package name and pulls this one in.
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 'wsh4-nmp' @ 1.0.0 (npm) as malicious.
It is considered malicious because:
- The package communicates with a domain associated with malicious activity.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for wsh4-nmp (version 1.0.0).
If you installed it — respond
wsh4-nmp 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 wsh4-nmp 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 wsh4-nmp-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.